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I decided to start a new thread because alot of people have said they were finished with the other one. 
After reading through the multitude of posts and the findings of the various members here are my thoughts on the air/fuel debate. AIR IS THE ROOT CAUSE OF THE PROBLEMS! That being said here is why I think this to be true. Air has better heat transfer qualities than diesel fuel, (It’s easier to raise the temperature of a specified volume of air 10 degrees, than to raise the temperature of the same volume of diesel fuel by 10 degrees). Now if there is, say 20% air in the system, you are left with 80% diesel fuel. The diesel fuel is heated to a higher temperature by the same amount of heat because of the reduced quantity of fuel. This is the temperature of the fuel is before it is compressed in the injector (which I would assume would raise the fuel temp. considerably,). The increase in fuel temperature caused by the injector, would then be increased, because of the decreased quantity of fuel available,(20% air, 80% fuel). Now keep this theory in mind as I jump to the next topic. If #6 fires right before #8, the shock waves generated could create Pat’s air which would be flowing directly to #8 and the end of the dead end rail. This would add to the air pocket (hot spot) in the fuel rail (prior to the tank and fuel line mods) at #8. The increased heat at this point would consequently reduce the lubricity of the fuel to this injector, along with not getting a full shot of fuel because of the air/fuel mix and cause premature injector wear. This would explain the high temps at #8. Ford’s fix was to increase the amount of fuel with the LL injector, which would give you the same amount of lubricity because of the increased quantity of fuel, even though it is heated and mixed with air. The regulator mod also contributed to the fix of these problems by allowing a return of fuel (and air) to the tank. The now, flowing fuel would pull heat from the heads and return it to the tank to dissipate. This explains why the trucks run so smooth after the tank and fuel line mods, the regulator mod, and the injector is replaced with the AD injector. The air has been effectively been removed from the system. This gives you a full shot of fuel when the injectors fire, there is no air to displace the fuel causing excess heat in the fuel, and the increased quantity of fuel (which is now flowing thanks to the regulator) in the system is dissipating the heat instead of building up. Don M stated in a previous post that he (or someone he knows) stated that they noticed fuel quality made a significant difference in the way the trucks ran. Is it possible that the fuel quality was confused with fuel quantity? By that I mean was the increase in the performance of the trucks due to the tanks being full, and the leaking fittings in the tank, were then being submerged reducing or eliminating the air in the system. By removing the air from the system it seems to solve all of the problems. This could be totally off base which is fine with me so feel free to comment. This is based on what everyone else has posted. |
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ACH I wish I could reach a satisfactory conclusion like you have. I think I have learned from reading all this info that that there are some fuel delivery issues. I also think most people who have devoted the most time to find the problem have identified AIR and SPILL FUEL in a dead end system as the problem. However, the recommended fix is not consistent with the identified problems. To remove air, all you need is a tiny bleed orfice. You do not need fuel flow. In fact a high rate of fuel flow (especially thru a restricted fitting like the inlet ck valve) will only aggrevate the situation. To absorb spill fuel pulses you need an accumulator. A diaphram type regulator will perform both tasks, just not correctly. A flow thru system regulated like the one that has been recommended as the fix will also remove, guess what,HEAT. This is why I am still on the fence scratching my head. |
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ACH, Maybe we can make this the kinder and more gentle thread that everyone will post on. This way we can collaborate ideas and come up with a verifiable and repeatable repair method. The problem I have with air being "root" is that Kim does not modify the factory fuel system. He states the factory fuel system is not the problem. He just modifies his injectors to deal with the conditions in the fuel rail. Further, even if he were Einstein he could NOT make an injector that would reject air and accept fuel if the fuel and air were both present in the rail directly below the area where the fuel is charged to the injector. I still feel that air is NOT "root". Maybe it contributes to a limited degree. Were is Pat Dolan? Don~ |
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ACH, Based on THIS and THIS I can't determine whether it is air released by these harmonic shockwaves that are cylinder/injector/firing event related or simply the geometry of the harmonics within the fuel rail or even the HP oil rail (can't identify where they come from), but I'm convinced that the root cause are these shockwaves and the harmonics they create. Because of the apparant extreme magnitude I would not rule out a combination of both. Unfortunately, lack of good and sufficient data prevented me from investigating this better. With that said I agree with the title of this thread but not necessarily what you have proposed as the "ROOT" cause. What you have proposed is one of many scenarios that I considered HERE in item #4. The fuel line and tank mods seem to have addressed the air in #1 along with any of the #2 air resulting from the mixing bowl and screening in the tank pickup system. The flow thru the heads have solved some of the types of air problems mentioned in #3 and #4, I just can't tell how much, but neither the fixed/variable orifce return or regulator return has eliminated this harmonic structure in the vehicles I have looked at but have only privately shared with the owners. Larry |
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Don M, I could be mistaken, but as I remember Kim said that the "factory fuel delivery system" was not the problem and that having a "constant pressure/flow to the fuel rails" also was not the issue, but a "constant pressure/flow to the injectors" was what was needed. These last two are not probably exact, but he made a distinction between the fuel rail and the injectors and it had to do with fuel to the injectors being the key. I'd have to do a lot of research to make sure I have the exact wording, but you have to really read Kim's words carefully and fully. At times leaving out or paraphrasing what he said changes what I feel he was actually saying, especially after he introduced the marketing end of his work. Larry |
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Don M Not to be insulting but, from a person that says do not jump to conclusions till you have all the data, to assume all Kim did is "just modified the injectors" is a big leap. Do you have inside information? If you read in the older posts on the other site, Kim jumped all over one person for stating just what you are. The only people who know what Kim is doing are not talking because of the NDA. If injectors are being changed in his kit, maybe it is because he found that one or two positions are constantly damaged. Or like many here that have changed their #8 injector, it is to get rid of the LL injector which can cause idle knock. But $500 dollars for 8 new injectors is a REALLY good deal. One that I want in on. So I think there is something else Kim is doing. Just had another thought, maybe if injectors are being changed, it is to get the 400HP he claims he can get. My understanding is the HP increase kits are quite a bit more expensive than the basic cackle fix. Bruce |
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As I understand it, the Kim Lux cackle kit is $500 and you have to supply your injectors as cores. And as far as I know, that's the only thing included in a basic kit. No, I've never signed an NDA so maybe this is wrong. But then again, anyone who knows for sure can't say, due to the NDA. So I guess we'll never know. |
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I've signed the NDA, but that really doesn't explain what is wrong or how Kim's solution fixes it. Has anybody tried feeding Number 8 from rear instead of the front? Has anybody put an accumulator out the back of head fuel rail? You might be able to change the dynamics of the heads fuel rail by feeding fuel from both ends? I'm not sold on the air problem either. My guess is replumbing the heads is changing the dynamics of the standing wave and harmonics that are happening in the heads. Kim made one statement a long time ago that has stuck with me. it was all PSD will develop the cackle sooner or later. |
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CKing, Good post Dude. We agree on some stuff. Don~ |
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Kim lux said all PSD will eventually cackle. As the plungers and barrels wear more fuel will slip past to the detriment of the pre- shot. TBROKER |
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CKing, In reply to: Maybe something like a tuned accumulator attached directly to the machining ports on the back of the heads of the HP galleries and/or Fuel rails so they are in the direct geometric path of the shockwaves. This IMHO could solve much, if the major problem are the harmonics or the direct shockwave reflections off the back of the HP galley and/or Fuel rail. If it is because of non reflected direct shockwaves then this has to be isolated from where it is causing the problem, don't think you can eliminate it since it probably has to do with the inherent design of the HEUI injectors. Again a lot of this is armchair guessing somewhat since a lot more research and analyses is needed. Larry |
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Larry, Do you know if the cackle fix from Kim Lux is working? Or does it work most of the time or some of the time? If it works, maybe for 500 bucks everyone should just pay the money and be done with it? Man I dont even now if that is an accurate cost or not, but I read it here a few times. 500 bucks if correct is easier to shell out than the alternative of reworking fuel delivery systems, tank mods, etc. Don~ |
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Don't forget that TT was able to even out the CP's on his 2002 with only an accumulator tubed to the drivers side rear test port. Could it be that the unbuffered action of the split shot is liberating air or vapor in the fuel rail and that by smoothing out those pressure waves with an accumulator the formation of vapor in the fuel rail is significantly reduced to the point that it is no longer a problem. TBROKER |
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Don, As far as I'm concerned the NDA make that a non-option. This forum is about sharing ideas...not selling them. Are you Kim Lux? Rob |
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Kim's injectors do not work on every vehicle. |
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Don M, Kim's kit is far more complex to install than the by-pass and regulator, and $500 is almost double what materials cost to install the by-pass & regulator set-up. |
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Im not Kim Lux. I dont know Kim Lux. Kim Lux is a ghost as far as I know. I read the cost for kit was 500 bucks. Maybe I am mistaken. Don~ |
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Why don't you go ask Kim Lux at diesel-central, be sure to register as the same name you use here so we can all follow your discussion with him. |
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Hutch wrote: "Kim's injectors do not work on every vehicle." Ok, so Kim's kit IS injectors that have been modified if the statement you made above is correct. So, is Kim making a magical injector that can reject air and accept fuel? The answer is already known. It is NO!! It is impossible. So, I still say the cackle is not an entrained air problem. Don~ |
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I'll put my money on the hard work that the good people of this forum came up with. It is half the price, and at least I see what I get for my money. |
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Don M, In reply to: No, but I made the comment in one of my posts that I would love to have a recording either directly or covertly of one of his "fixed" trucks and as I understand it this is strickly forbidden in his NDA and IMHO I can understand now why. He indicted at one time he was going to post one, but I highly doubt that that ever happened. I do have several sound clips of the before mod of one of his first beta units. I have however seen and processed several interesting waves on two trucks that have somewhat abnormal harmonic structures in as I remember the 3rd to about 5th harmonics and have shared this information with them. Before anyone asks if you look HERE where I was trying to gather information, both there and off line I did not and have not made the information public unless the owner has specifically authorized it. I'm not trying to hide anything, but just felt it was their info and they controlled it, I was just trying to give them more insight. All these people know this and until they give me specific permission to make their info public only the owners of the vehicles and 2 to 3 others have had access to it. Let me state I never got my Non cackler/knocker wave before I had to send the equipment back, which was disappointing and was a major desire in my validation efforts. Larry |
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mtk Even still to get 8 reman injectors for $500 is still a good deal. I was quoted $98 in labor alone/injector (Alaska prices). Then add what ever the parts cost. Bruce |
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Don, I had to ask. Kim and his oath of secrecy turned off many people. That is where this all began and many people have openly shared their ideas, knowledge and time here. Again I find myself agreeing with Mitley_350…. no snake oil for me. Rob |
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Larry, Your harmonic structure info sounds, no pun intended to be very intersting. I dismissed it at first and should have read it more carefully. I apologize. I am looking at it all now in full on your page. I did briefly look at it on day one, but it did not soak in as well as it should have. Thanks, Don~ |
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Don M, If you would think there are ways to help injectors pass air, think. Did you do as I asked? Go ask Kim at diesel central about your theory. Entrained air in the fuel and "raw" air leaks in the suction lines are 2 different issues, raw air in the fuel supply WILL CAUSE CACKLE. |
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Larry, Tell me what you found with the test manifold on the black truck. Excuse my ignorance, but what are the plots of the F-D website of? Are they the .wav files of trucks with no cackle? It does say something at the bottom of the pictures about no cackle, but I wanted to be sure. Hutch, Kim aint gonna post the answers to his repairs Man. You already know what they are anyway right? Don~ |
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Don M, if you just heard of Kim Lux yesterday how do you know he will not respond? He has responded SEVERAL times to my questions in an open forum at deisel central. Give him a try, he's a smart guy, you two might hit it off like "two peas in a pod" 
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TBROKER, In reply to: I have always been aware of TTs work and that with the regualtor mod he has evened out the CP's on audible cacklers and has the data to support that and that is one way to address this uneven CP problem on #8. Can't remember using only the accumulator evening out the CP's and would have to double check that, since that would be interesting. I do find it interesting his lastest comment on the non audible cackler having as I think he indicated a CP problem and this has always been my concern that Cackle doesn't have to be heard to be there causing potential damage and is why I took the approach that I did here to not use my feeble ears, but something that can hear what I can't. In reply to: I don't know since that is only one of the potential effects of shockwaves and harmonics, but I think it has been shown that the accumulator is not the source of the improvement, it is the regulator/flow setup which will definitely give a potential path for air removal that wasn't there before. If the acoustic structure I've seen for cacklers is correct, I can't comment much further since I never processed one of TT's trucks to my knowledge. The following are just SWAGS so take them as such: 1. I don't think just the accumulator as plumbed at all these wierd anges using the test ports will dampen the shockwaves or remove the harmonics. 2. The flow thru the heads will remove air, but might also be creating air and I don't see how it would help with the shockwaves or harmonics except for the fact that the fluid is now moving so their maybe some frequency streaching-but this technical area is beyond my expertise. In addition to evening out the CPs as shown with TT's hard data, it evidently does help with audible cackle and changes the way the engine sounds, seems to improve performance and mpg, but I haven't seen any hard data as to exactly why only testimonials. I have observed a homogenizing effect in moving fuel with visible air in it especially when it hits an obstruction or rough surface. Larry |
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Larry, I am amazed at what you are doing. Can you help me dechipher the graphs? Are the peaks and valleys what you are referring to? Or is it the horizontal lenght that is the concern? Thanks, Shane |
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Don M, I have a very serious question to ask, let's say the fuel is getting hot and thin enough to loose it's sealing properties in the plunger and barrel assembly, what happens? Be serious and direct. Please, do not dodge this question, what happens to the fuel in the rail? |
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Hutch, First you tell me I dodge questions and then you want me to answer another. Be nice and I will answer you questions without bias and give you the help you asked for. What happens to the fuel in the rail or what happens in general? The question you asked is two part? Confused. Don~ |
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CKing The feeding of the head from the rear was tried about two years ago and the consensus was it did not work. I also wonder if the flowing fuel is damping the shockwaves and the harmonics. If you throw a rock into a standing or slow moving pool of water you can see the shockwaves (ripples) traveling across the water. But, throw a rock into a flowing steam and the shock waves are greatly reduced and swept down stream. After thinking about this overnight and running it pasts Larry M for for possible errors, hows this for a theory, it includes all theories mentioned and may explain why doing only one part of the fix does not necessarily "fix" the problem: 1. Shockwaves and harmonics from the #6 and #8 firing order are creating Pat air (and/or foam) at the injector fill port and in the fuel rail. This air is going through the injectors causing the loss of the split-shot, which causes cackle. The air also causes the injector to wear. And once worn, this can cause the missed split-shot and also gives us cackle. Talking to an X-Ford mechanic he said that it was very common to find more than one injector damaged. He also said that even though #8 was the primary cuplrit for the cackle, they sometimes found other injectors would cause cackle. 2. Temperature is adding to the problem by it's effects on the fuel lubricating properties (ie accelerating wear) and Pat air (air expanding in the fuel rail taking up space for fuel) along with changing tolerances inside the injector (getting sloppy after they warm up). Any of these will either cause or at least contribute to the loss of the split-shot and ...yada, yada, yada, ya... 3. When present, the Hutch air is just plain overloading the fuel system with air. If it gets past the little bleed hole in the fuel filter and into the fuel rail, it raises havoc with everything. In general, just a royal pain in the ars. Bruce |
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Don M, In reply to: I assume you mean the Deep Emerald Green Van on my webshots site that is my vehicle -Read my post on page 43 of THIS THREAD and my post HERE In reply to: If you go the the downloads of this website the titles of the plots correspond to the wave files there. I let others listen to the waves with their ears and look at the plots and make their own determination - I see a non audible cackler hiding out there but I've been wrong before and so have some wave files been mislabeled.
Larry |
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Hutch, First you tell me I dodge questions and then you want me to answer another. Be nice and I will answer you questions without bias and give you the help you asked for. What happens to the fuel in the rail or what happens in general? The question you asked is two part? Confused. Don~ --------------------------------------------------------- Just as I thought, you don't know. I did not ask for help, I know what is happening to the fuel in the fuel rails, you do not. |
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Hutch, Im just trying to clarify your question/s that is all. I wanted to make sure the question you asked me was understood between the two of us before I answerd a question you did not even ask. Did that make sense? You are assuming I dont know the answer to the question just like you assume the data you interpret is final, godlike, and the law. Lighten up. So far you are the only antagonist posting on this thread. Everyone else is being nice. Don~ |
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Larry, I just had an epiphany after reading that. I aint gonna puke it out yet, but Dude you may be onto something here. Did you do a pressure wave test on the rail for spikes or harmonics or are the plots all from audible .wav files of engines running? Sorry about the mis read on the truck/van thing. Don~ |
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beantown, Well I was doing, but not for now since I had to ship the equip back to the over generous Indian Giver that I was able to borrow it from temporarily. I will early tomorrow try and work up something that makes sense, but for now what you are seeing is the FFT of the time domain wave form recorded or in the case of my vehicle measured and is a frequency domain plot of the frequency in the horiziontal and the level of that frequency in Db in the vertical. Almost all plots are from 0-100Hz with as I remember it a 2.5Hz resolution sampled at 2.56 the highest freq sampled to prevent aliasing. The horiziontal dotted lines are 10db and the set of vertical lines are the harmonic freq shown for the base freq in the lower left of each plot. Absolute Db values are meaningless except for my vehicle since it was recorded in the vehicle itself. What I looked at was the vertical peaks along with the relative strength of the harmonic peaks in relation to the avg baseline levels. Remember Dbs are related to 10log of I**2. The data is a numerical averaging of the envelope processing (i.e. absolute value of the amplitude excursions in the time domain) for a sample on the order of about 10sec. Let me say, I'm no acoustic expert in all this and haven't done this at this level of detail in over 20 years so I've probably forgotten more than I ever thought I new back then. Don't feel bad that some of this seems esoteric because it still is to a large degree to me now. I tried to enlist some help from an expert in this field (PhD EE with over 20 years in R&D with the gov't), but don't hold out much hope so we're kind of stuck in making real sense out of this limited amount of data. What is IMHO important is the freq plots for my particular vehicle when I could hear it knock and when I thought the knock was gone. Also look at all my freq plots I did for the cackle rpms and compare them to the limited sets of other vehicles for which the owner have given their permission to make them public.
Larry |
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Don M , what happens the the fuel inside the fuel rail during even a "normal" split shot cycle? Please answer the question. |
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KB, I find no serious faults as we have previously discussed in anything you said, there maybe differences of opinion in some minor areas, but then again they are our opinions (ON EDIT no one has hard data to vaidate any particular scenario yet - so opinions are just that opinions - yours is just as good as mine  ). There could be other scenarios as well I just don't know which and how much of the several is the right combo. Biggest problem is this is one of the worst mediums to work out these complex technical discussions and really come to an understanding, but it's the best we have so far. We need a conference with a flip pad and magic marker on an easel and two days maybe more in face to face discussions along with some disinterested experts to keep us on track and honest to really make progress.
Larry Edited by Larry M (05/09/02 08:07 PM) |
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Hutch wrote "Don M , what happens the the fuel inside the fuel rail during even a "normal" split shot cycle? Please answer the question." Leak off! Don~ edit- if you are asking what the injector does. Edited by Don M (05/09/02 07:47 PM) |
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Don M, I tend to believe that too. Now Don let me make something absolutely clear which I think you now appreciate - I have answered all your questions so far in this thread, but please, pretty please don't start riddles or questions with questions or like I did in the other two I will become silent. I think you have a lot to add, but please add constructively - OFF the soapbox, just had to say that and this is my problem since this is the way I operate - peace 
Unfortunately all this was audible, but for my vehicle is is actual real calibrated data for the location of the microphone and absolutely in the case of my vehicle it is running under slight throttle at around 2 psi boost uphill for non idle condition with I think one exception where I was stationary with a 900rpm idle. I was trying to get my vehicle to cackle audibly which I never could do. I wanted/wished/drooled over have mulitple channel DAS with accelerometers/pressure transducers (they do get expensive for the HP oil galleries  ) along with high quality calibrated recording equip for various triggers (i.e. especially injectors, IPR, etc.), but I had to work with what my over generous Indian Giver for which I personally am forever indebited could get to me for the short time I was able to use it. Also my vehicle with this and the fuel test manifold was getting hard to physically get into. As I said the biggest regret is I could not get enough interested participants to provide data so the data I have I put in the very very interesting area but I would not go out and bet the bank on it just yet. It is only a first step, but I felt it was a step and an important one that I could take to potentially help others with this malady.
Larry |
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Nope we don't have a conference room but we got the next best thing thanks to Jason. The Chat room!!! Pick a night a go in there and hash out some of this stuff. At least everybody can talk in real time. Hey, ya never know, it might work, stranger thing have happened. See ya, Shane |
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Leak off! Don ---------------------------------------------------------- From where, and what does this leakage cause? |
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Hutch, The leakage is passing between the fitted parts and injected back into the rail. This leakage of the fitted parts is from the fuel oil being less viscous from heat and the less than perfect tolerances in the injectors. Don~ |
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Larry, I was hoping some of the measurements were from the rail itself. Can you get harmonic measurements from the rail? Looks like all PSD's cackle from the data you have at least all cackle in some level of severity. Were any after a Kim Lux kit was installed? Don~ |
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beantown, I've tried that back in my Naval system acquisition days and in this case you need bodies with their documents, a zerox, tape recording facilities, flip charts, etc. etc. It's the old someone is looking at his piece of paper and trying to make a point or contribute and someone simply walks over with a pencil and points to his particular piece of paper and changes the whole direction of the discussion. I've basically done the chat room thing, but typing is no substitute for a verbal exchange with the ability of graphic representations. JMHO Larry |
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The leakage is passing between the fitted parts and injected back into the rail. This leakage of the fitted parts is from the fuel oil being less viscous from heat and the less than perfect tolerances in the injectors. ----------------------------------------------------------- At what temperature and pressure does this leaking fuel exit the injector at as it re-enters the fuel rail? And what happens to the fuel in the rail? |
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I, like others have been following most of these threads closely. i feel i must throw my 2 cents in. i have been a diesel mechanic for 22 years. i do not claim to be a know-it-all, but i have worked on all the heavy duty class 8 diesels out there at one time or another. i have worked on and around farm tractors most of my life. i have worked on mechanical systems and electronic systems and they have one thing in common, they need clean,un-airated fuel. none of those engines uses a closed fuel system. they all route fuel thru the head (except those with direct injection). a secondary function of this is to ensure a fresh,consistant temp. fuel supply. it also prevents air pockets. so.. when i looked at mt state of the art new powerstroke, i scratched my head. when i developed some odd sounds from under my hood,i looked closer.when i found this website i was amazed. i wasn't the only one. i also knew it shouldn't sound like that. i found others that knew things weren't right and were doing something about it. TT,Hutch,Bob,and others were already righting the wrongs of this fuel system. yes,there may be other things contributing to this phenomonon,but it is a fact that this stock fuel system is NOT ok. the blending in the tank, the poor fitting connections,the pressure drop across the check valves(flow valves as f..d calls them), the dead ends at the heads,and the regulator at the wrong end of the system cannot be ignored. the varied results dont mean that the modifications dont work,it means that there is more to learn. theories and philosophies and stuborness dont fix engines,intelligent persistance does. I for one dont think anyone should hinder that. THANK YOU. |
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Don M, In reply to: Sorry, me too but the equip was for a calibrated microphone and not a calibrated transducer/accelerometer and even that would not as I understand it show harmonics since these sense in the time domain and harmonics or standing waves while detectable in the freq domain via acoustic measurements are extremely hard to capture with spatial measuring devices. The only fuel rail measurements were average fuel pressure via the driver's side rear test port (mine constantly ran 65-70psi). That was by a digital gauge and transducer good I think to at least 1psi and probably a lot closer. I did get peaks of over 180psi, but have do data and don't understand how the borrowed instrument really calculated that. Others do have good fuel rail pressure variation plots. In reply to: Which of my plots at speed do you see cackle and what makes you conclude that (a non answer here is a problem for me since for me it does not contribute ), I did document Idle knock and no idle knock. All the rest, yes that was the whole point of me wanting to see a virgin so to speak - Sorry no sexual connotation just couldn't think of a better word. Except for mine I have seen no non cacklers
Larry In reply to:not unless someone sent me one and either did not identify it as such or sent me one that has not given his permission to make it public yet. I will say there are either 4 or 5 non public sets of data that I have and will for the reasons I have stated previously will remain so unless I get permission to make them public. Larry |
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Larry, You got a pressure reading of 180 psi once? That is odd or abnormal IMO. Don~ |
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Don M, That was a peak not avg and I can't tell you how the digital readout calculated that. I was simply using what my generous Indian Giver graciously loaned me. Unless we understand what that meant it maybe meaningless and now I should have never mentioned it because I can't speak to the techincal significance of that. I did in general remember seeing only a 130/140 peak, the 180 was the highest and have no idea of correlation as to hot/cold/idle/etc. since that was not a parameter I was trying to document - it was only a secondary observation that I interpert as the extreme and it is also based on sampling frequency of the tranducer all of which I have no information or techinical knowlege to accurately interpert.
Larry |
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You guys are measuring the split shot feed back at the wrong place. The barrel of the injector covers the spill-over port and the split shot feed-back is INSIDE the injector, what you are reading is a VERY diluted pulse of the original pressure surge that has traveled out the fill port and into a MUCH larger volume of fuel in comparison to the amount of fuel spilled over which SERIOUSLY diluts the readings you are taking, this spill over actually occurs INSIDE the injector. Now, at what temperature and what pressure does the spill-over fuel exit the barrel assembly INSIDE the injector? Edited by hutchinaugusta (05/09/02 09:10 PM) |
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Here is something I got off the dieselmans site. On how the injector operates. Because of the nature of how this system operates, air in the fuel is not as great of a concern as air in the oil. The PowerStroke requires a special anti-foaming agent in its oil to prevent this aeration. Oils with an API service rating of CF-4 or CG-4 already have this agent, but it becomes depleated as the oil breaks down, so regular oil changes (3000-5000 miles depending on vehicle use) are necessary. The anti-foaming agent can also be depleated by interaction with some silicone sealers. Sod dude |
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Hutch, I was never trying to measure anything except the avg pressure in the rail itself with basicaly a lab grade instrument which I did instead as everyone else has a pressure gauge outside the rail. If you mis understood what I was measuring, I'm sorry for misleading you. I now wish I had never mentioned this peak thing because I cannot expalin what it was - it was what the readout box said. Anyway, this is not something to concentrate on here, it's shockwaves and harmonics discussion which you obviously do not believe in
BTW out of respect I will always post first with either the username or a first name out of courtesty and include either my username or real name in closing. Larry |
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Dieselman specifically said air in the fuel is not a problem??? Or did he say foaming of the oil is a problem? I'll tell ya air in the fuel supply is a HUGH problem on any diesel engine, anyone who understands the hydraulics of a diesel fuel system will tell you the same, there is not suppose to be ANY air in the fuel. |
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Hutch wrote "there is not suppose to be ANY air in the fuel." Luckily there is not much to worry about huh? Don~ |
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Larry, that was not directed at you, Don M does not understand the issue here and I am trying to get him to comprehend what I've been trying to tell him, what the answer is to the "ROOT" problem, he will not take anyones word for it so he must be brought to the answer, which if he will answer the questions he would come to the same conclusion that Doug, Pat, Idssteve, myself and others have come to UNDERSTAND and appreciate. |
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Not after the tank mods there isn't much if any air to worry about. Why are you dodging the questions? You see where this is leading don't you? You've backed yourself into a corner and cannot find your way out, haven't you?
Come on smart guy, what is the fuel temperature and pressure as it exits the spill-over port, or here is an easy one for ya, how much HP oil pressure and resultant fuel pressure is required to unseat the spray nozzel plunger? |
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Hutch wrote "Why are you dodging the questions?" What are you talking about? Did I miss something? Hutch wrote "You see where this is leading don't you? You've backed yourself into a corner and cannot find your way out, haven't you?" Hutch your assuming again like you did a few posts up. "Backed into a corner" is rediculous. Stop assuming please. Hutch wrote " Come on smart guy, what is the fuel temperature and pressure as it exits the spill-over port, or here is an easy one for ya, how much HP oil pressure and resultant fuel pressure is required to unseat the spray nozzel plunger?" Its intuitively apparent you are being a smarty pants again when asking me questions. You ain't gettin' no answers from me acting that way. Once again try and be nice. This IS the nice thread remember? Don~ |
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I've been working on my truck. The threads in most sites move at about the rate of a glacier, but some on this site move more like an avalanche (not the Chebby one either). I have only had a chance to skim through this thread, but, if I may, I will try to throw in my Grand Unified Theory: I believe that air - or a lack of fuel - IS the problem. However, as Mr. Lux has so adequately demonstrated, the problem(s) is(are) occuring in the injector. Is the rail or the injector the problem? The answer is neither or both, depending on whether you sell injectors or fuel rails. My best guess is that a low pressure condition exists in the rail at the inlet area for one or more injectors when the injector is trying to fill. I believe that low pressure exists due to harmonics in the fuel rail, plus the hydraulic mass flows induced by adjacent fills (especially #6/8 event). I stick with resonance as a major player because of the full octave spread of the observed phenomenae. The injector fill event is fairly violent, and, combined with the rail deficiencies, could result in the plunger lifting with one of two things happening: a) dropping pressure enough to liberate air in the injector or b) finish raising before all of the available fuel is in (leaving a vacuum). Either one will let the pre-shot skip. Another clue here is that factory tries to spend more time delivering the pre-shot with LL#8, so they seem to expect there to be an incomplete fill (also mechanically delays the main shot). Free air entering the rail will simply throw the whole process in the garbage, but that is what the factory filter/regulator assembly is SUPPOSED to eliminate first. As far as fixing the problem goes, I see no conflict in more than one thing being able to affect a similar result. Feeding the #8 injector from both sides (the main feature of TT fix) does most of it, but I know from my own experience, not all. The stable hydraulic pressure of the end-of-rail regulation seems to make the condition in the fuel rail overcome whatever is going on in the injector. Perhaps the change in resonant frequency of the rail also contributes. Why do I say this with such confidence? TT's CP traces tell the whole story. Now, can Mr. Lux cure this with injectors? Why not? Determine what happens that can cause the super low pressure INSIDE the filling chamber and eliminate that problem. It may be as simple as removing some restriction at the fill port. After all, there is still fuel there, if you can get a clean fill of it into the chamber, you can deliver the correct quantity at the correct time (IF the injector itself and HP work right). Of course, I don't actually know. What I do know, is we cannot seem to bring KL to the table to post CP curves from pre and post-mod trucks. Wear in the injectors allowing a pre-shot to skip would also result in an idle knock, first phase spike, wrong actual injection time, all of that stuff. If that is the case, all PSD's will eventually cackle. No arguement. Heat in or from the air is not an issue. The mass of air in any instance is so miniscule that its heat capacity is negligible. I don't think temperature of fuel is an immediate problem, but I do believe that in the long run, cool fuel will be much kinder to the injectors. In other words, if all PSD's eventually cackle, this may buy some more good miles before remedial work is required. The HP stuff is completely unrelated to the FILLING events in the fuel side, which is when the knock and cackle monster is let out of the cage. Other than that, any improvement on that side has to lead to better consistency on the fuel DELIVERY cycle, which cannot do anything but make the engine run better. However, if the filling isn't right, HX is of no FINAL value (i.e. it is a solution to a different deficiency). Hate to sound so inflexible and conclusive, but I have to leave for the East in a day or two, and can't get back here for a while, so might as well put all of my cards on the table. Pat |
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Post deleted by Pat Dolan |
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i have some 0 to 1000 psi digital pressure gauges with a 25 pin port on them for computer hookup,good used condition,would these be of any help on this problem? |
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Don, I don't need any answers from you, this has all been hashed out months ago, you my friend are the one in need of assistance. Since you have never gone back and read the cackle thread like you have been asked to do many times so you would be "up to speed" there are allot of things you do not know and aparently do not want to know. If you want to really know what the root cause of cackle is just play the game and I'll walk you through what is occuring, but you have to think and answer the questions for yourself. If you don't answer the questions you will only be seen as someone only looking to antagonize and aggrivate people and your credibility will be -0. |
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Hutch, I threw in my thoughts. I can't and don't want to try and force anyone to accept what I have suggested. Disbelievers can still disbelieve. We are born with an abundance of choice and everyone can make the choice to not give my theory another thought. No hard feelings. No insults to disbelievers will be leveled. There are so many fixes and repair scenerios going around some have shown choice fatigue. Some of these choices are for monetary gain. Not a bad thing, but we can seek the shortest distance between someone else's assets and ourselves - or we can create some of our own. There will always be those who prefer plunder to the plow. After hearing the entire Kim Lux mess today and the delays I can guess which he prefers. Personally, I am tired and even forgot to turn off my sprinkler all day. I watered the same spot for hours. I want to get away from the back and forth and fussing. I want to get back to doing other things. Three plus days now and I have not advanced the effort any further along or proven my case to the elders in the cackle issue. I am not upset with any of you, just tired of fussing. Don~ |
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he?? if this guy (don) cant water his yard properly I sure dont think he has the capability to comprehend the problem at hand!!!!!! Maybe he needs to keep a check on his sprinkler instead of pretending he has knowledge on something that by his lack of REAL information he knows little or nothing about!!!!! |
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crecelius wrote "he?? if this guy (don) cant water his yard properly I sure dont think he has the capability to comprehend the problem at hand!!!!!! " To make things worse, it is now raining )-: Don~ |
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Hutch, In reply to: If that was the case, then I apologize since I was only seeing whose post you were refering to and you had no names indicating who you were directing your comments to. As far as understanding the issue I don't know including myself who acutally understands it to be honest with you. This thread proposed one theory as Air being the "ROOT" cause which based on your opinion HERE you agree with. I have a different opinion based on the actual acoustic data that I have collected on both cacklers/knockers and my non cackling and ocassionally knocking vehicle. I have never doubted that air can cause problems, but I just don't believe as you do it is the ROOT cause. I think it is much more complicated than any of us so far really comprehend. While I do not mean to speak for TT/Doug I do need to refer to some of his statements and my interpertations of them since outside of my data(which I believe is directly related, but lacks verification for me to call it a personal conclusion), he is the only other person who has actual data that is related to this phenomenon. So if I mis interpertate something I will bow out to his correcting me and welcome it. Even TT in his post HERE when he said: Why aren't the injectors being completely and consistently being filled. One cause is the turbulance is the fuel rail caused by the split shot action of the injector return fuel back to the common rail under much higher pressures and temperatures. The pressure and temperature data that we collected back in January shows these variations. stated his belief as to one cause based on his data. However, he then went on to say Are these pressures and temperature variations enough to cause partial filling? Well, I can't say directly that it does, but when we started to return fuel from the rail, we were able to stabilize the CPs (cylinder pressures) and this is a key measure of the operation of a diesel motor. So, apparently providing a constant flow of cooler fuel through the rail allowed the injectors to fill completely consistently. Where it appears from his data can not attribute the pressure variations as the direct cause, but even without addressing air directly the initial mods were all directed a these pressure variation. Since this thread is about the "ROOT" cause my contention is that based on the differences in the plots(i.e. the cylinder/injector/firing event related base freq and harmonic structure) of my vehicle with known audible cacklers and even in my vehicle the dramatic differences when I can hear an audible knock and not hear an audible knock, and I have no visible air issues, which is all that we can measure at presence, that the "ROOT" cause is as I have previously stated is not Air, but these shockwaves and/or the harmonics. However as TT goes on to say and in fact as I previously posted this flow thru the heads does even out the CP of #8 with respect to the other cylinders in this head. I do find the last three words interesting and something that has been stuck in the back of my mind. While TT used the words "allowed the injectors to fill completely consistently" I might have said "allowed #8 injector to fill consistently as others in the driver's side head are currently filled". I'm not ready nor have I seen the data or if it's there maybe I just don't understand it, but I would like to be able to say that "in my engine all my injectors are being filled uniformly and properly" IMHO there is a subtle, but important difference here. The next paragraph in TT's referenced post confirms that enough air can cause not only #8, but other injectors to not properly fill such as #6 and #4 to the point of being noticed. This to my recollection is the first time this data has been revealed unless I've simply missed it and kind adds to my belief that Air is not the ROOT cause of knock/cackle, but something else. It would be interesting to see the CP plots of this experiment. In another post by TT HERE he states: On the trucks that I have modified with the fuel return and Hutch's tank mods, we still see slight foaming at the fuel return after the regulator. It generally happens at startup and after a full load run on the dyno when the motor is returning to idle. It generally takes 3 to 5 seconds to clear. Is that Hutch's air or Pat's air? I really don't care, that least it is not going through the injectors Which I find interesting since this is on a fully Hutched/TT mod vehicle where air if it was the ROOT cause of this problem should not be in play, but not sure if I could go quite so far as eliminating the possibility that some of this air is not going thru the injectors. True the CPs are balanced, but are they all optimum - I don't know nor do I know what is producing this foaming or exactly what effect it is actually having. If the ROOT cause is as I believe then since we really haven't removed the shockwave and even in the one vehicle that has all these mods that I have looked at there still is some harmonic structure, but it has changed somewhat, which makes some intuitive sense to me, exactly what problem have we solved except to even out the CPs. This is not to say this result is bad, obviously this has to happen. I would have loved to see a Hutched/TT mod vehicle show an acoustic pattern like mine and then I would be considering that the ROOT problem has been addressed and eliminated. Thus far based on everything I've personally done, I can't consider that possibility yet. The situation has improved dramatically, but has the problem been solved - I don't know. Finally I find the last paragraph of TT's post most interesting and based on my work agree, Just because you can't hear it, it might still be lurking there and causing yet unkown problems including CP imbalances. Sorry for the length, but there was a lot I had to try and get across and this is not an easy topic to cover well using this medium. Larry |
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beantown, As promised here is more to help you or others along: If you look at one of my plots here is what the various data and parameter settings mean: ALONG the bottom: On the left is the frequency of the marker(small open square with cross hairs on top of 1st spike) in Hz On the right is the level in dB of that spike (I didn't worry to much about absolutes, but as I remember like for my vehicle this number needs to be added to the Level range to get the true dB level and then that is re: to the setting in Menu(1) for 0dBEU(i.e. 0db using engineering units which in my case was -124 and has to do with the microphone calibration) ALONG the right side: SPEC: indicates the display is a spectrum analysis and the white bar means the instrument was in the averaging mode, the other being an instantenous mode. PSE/RCL: indicates whether the instrument was paused or if a data set was being recalled from the memory in the machine. Except for my vehicle and a couple of others it was normally a PSE display. For mine since I was doing the data collection real time in the vehicle I stored the data and then recalled and printed it out off line. MANU: just indicates the type of storing scheme and I used MANU always. log: is the level scale for the y-axis and here it was to represent dbs y = 1:y-axis enlargement factor x = 1:x-axis enlargement factor *4: this is the FFT zoom factor and from my understanding it is how many samples go into the FFT. It can be selected as 1,2,4,8. I selected 4 based on some testing and if anyone wants to go further into this we can do it off line since this is kind of an esoteric thingee and I now don't even have the manual to refer to so going into this much further could be very time consuming. Window: This is the sampling window used and I selected "HANN" the Hanning sampling window based on by research on the internet. Trigger setting: I selected "FREE" to see all the data and used the internal trigger in the equip. This instrument is capable of a lot more such as external trigger etc. that I neither had the equip or expertise to utilize properly. In the hands of a true professional this could really be much more enlightening that what I was able to get out of it. Averaging setting: This has to do with how when the instrument is in the averaging function it performs the averaging. I selected "LIN" for linear which simply add each sample set numerically and then divides the number by the number of samples used. 100: this is the range in Hz for the x-axis and is what was normal used. I can't remember which ones, but a couple of plots I used 200 and may have in a couple set the x-axis enlargement for 2 which in that case the display would then be 1/2 of this number. I first checked to see if there were any higher interesting freqs, but did not see anything. Not to say there might not be something up there, I just didn't see it. Level range: the initial sensitivity for the plots, it just ensures you don't over drive the instrument and is used to get the true dB level which for my purposes was not really a concern, I was more concerned with the relative information and structure. dBEU: this refers to how the actual dB is calculated and displayed based on the the pickup device and is the for matching the characterics of the calibrated microphone to the instrument. Finally, HERE is a basic primer on FFT processing that you might find interesting and HERE is a little more info on the SA-77 analyzer I used for all this. NOTE: you don't need to download the text thing, just hit cancel and you'll get the html page, I didn't want to wait the 23 min or so for the download
Hope I got all this right and that it helps some, Larry |
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Pat, In reply to: In reply to: In reply to: In reply to: In reply to: Question is ROOT cause with AIR being the guilty party, looks like you voted several times - how many hands are you playing
Larry |
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DonM, I'm impressed from the looks of your last post it might appear you have changed since the raging oil debate over at TDR. I'm sure you remember it well. Are you a lawyer? If you are I could use a mouth like yours on a pet project of mine. Take it as a compliment it was meant to be! I hope your not comaring your 97 PSD to a 99 and up. Different animal altogether. OK and the big question still remains, how close are you to figuring out the root cause? What other data do you need to achieve that goal? This is a very resourcefull group and I am sure by either asking us for the data or searching you'll find it. Oh by the way have you noticed how much more cooperation you now have by starting your own thread on your theory? To bring you up on a little more history, The Kim Lux fix went after the problem from the exact oppsite end of the fuel system. The combo of the TT/Hutch mods attacked it from start to finish in the direction of fuel flow. It has always been my intention to put the Hutch/TT mods on a Kim Lux kit truck and get it on a test machine. The test results will either create pandamonium with the KL fans or he'll really be over his head with back orders. Could it be the ultimate fix? Man you have know idea what that would do! Imagine if the combination of the three fixes could solve this thing once and for all. Then maybe we could figure out the dam drone that drive alot of us crazy! One other thing that has been bugging me Don, WHY do you have such a big interest in this all of the sudden? Make it short and sweet and please leave the cast of Batman out of your answer. Thanks, Shane |
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Larry: Using "air" somwhat for dramatic effect, but with some good reason. I might have paraphrased all with "inconsistant filling", but in the event that an injector does not fill, one of two things must happen: a) the void remains as a high vacuum or b) once the pressure drops below the degassing point (approx 4mb) air will be liberated. In fact it does not matter which condition exists, when the injector tries to deliver, it will "skip" that far ahead at a higher rate (no hydraulic resistance from fuel plunger to slow travel) and bang a charge into the chamber by liberating the energy gained during the accerleration phase of the "skipping" event. Obiously, measuring the pressure in the void is pretty much impossible, but I cannot imagine it being any less than balanced by the forces that should eliminate a theoretically "complete" vacuum, and this force would be the vapour pressure of whatever off-gas component is available at that pressure and temerature, which, in the case of diesel fuel, will be - AIR. BTW, your TT quote about a Hutched truck releasing air after a hard run I do find most appropriate evidence that these conditions are occuring not only in the injector, but somewhere else in the rail (CV's ?, resonant point?). I fully agree with you, air itself is not the problem, it is the conditions under which the injector can set this scenario up to play out. To which, I re-iterate, and change in the overall system that changes a critical variable may be able to "cure" a cackler, be it from the rail side or the injector side. Air, however, is the physical evidence and evil handmaiden of the cackle-pig's virus. Hutch's air is a completely different matter. It just simply has no business being in a diesel fuel system. If, however, some of "my" air is liberated at the CV's (for instance) in the dead end rail, it would then become Hutch's air and indeed would cause miss-injection. Agreed, CV would then be the problem, or maybe a fuel system so intolerant by design of its own inherent shortcomings. In this case, we should then paraphrase the real problem as ineptitude. BTW, any idea from you measurements so far as to what the actual resonant frequency of the fuel in the rail might be? Just curiosity, since just the spill spike alone could cause all of the difficulties before being dampened out in even a single complete cycle. Regards - Pat |
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Here are just some interesting connections I have found from reading all of these threads Larry referenced Doug (TT) as saying In reply to: Also, in Kims post just under two years ago (worth reading) http://forums.thedieselstop.com/ubbthreads/showthreaded.php?Cat=&Board=UBB15&Number=201973&page=60&view=collapsed&sb=5 He states the following In reply to: and In reply to: I find the following things interesting, 1. These topics were discussed just under two years ago, though many of the people on the forum today were not around then (including myself) 2. Some of the findings Doug found parallel some of the findings Kim was trying to report before he went into seclusion. 3. At first some may attribute the air / foam build up found by Kim to air leaking into the fuel system supply, but since Doug found the same thing after the modifications were completed leads one to think that there is another root cause of the foamy fuel. 4. Some people have posted they heard out gasing through their post fuel rail regulator, this may be caused by the foaming fuel. By no means do I mean this post to take away from any idea proposed, I just believe that many of those reading these recent threads (including myself) should go back and read all of the archived threads so nicely found by Larry M in this thread http://forums.ford-diesel.com/ubbthreads/showthreaded.php?Cat=&Board=UBB33&Number=729293 One more thing, since several people are up in arms about "Pats Air" and small orifices, what do you think about the fuel having to travel through the small injector fill ports into a low pressure cavity? If you are worried about threads in a T junction within the tank causing "Pats Air" (for the filter screens) as I read in one post, just think about the fuel path through the injector; most likely much worse. My point is that though "Pats Air" may be a factor with various components in the fuel system, its probably not he devil that everyone makes it to be. I.e. potential "Pats air" caused by the CV's is probably not that bad for a stock fuel system, though the extra flow of moving the regulator post fuel rails may change things. That's all for now. Back to being the fly on the wall. L.J. Edited by ljthawk (05/10/02 04:48 PM) |
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Pat, In reply to: No argument on air of any type and I don't know enough about actual injector operations. Based on the magnitude of these pressure spikes if I had to place my $2 bet I would bet on them being the source. All I'm doing is indicating what I believe is the ROOT cause which is what this thread was basically started about and proposed Air as the ROOT cause to which I disagree for all the reasons I've given. Air/foam is the result of some process which whatever causes that process is what I call the ROOT of the problem. The one scenario I haven't ruled out is that it is simply the physical occurance (i.e. w/o air) of either the basic shockwave, a reflected shockwave, or a harmonic hitting the offending part/injector just at the right time and in doing so causing it not to fill and operate properly. That is why I have said it's the shockwaves and/or harmonics and not the air as being the ROOT cause. What if a simple dispersion device was inserted in the machining plugs in the fuel rail(somewhere I think I read there maybe one at each end) so that the direct shockwave problem is not eliminated, but as you suggest we physically change the geometry to both reflected shockwaves and potential harmonic geometries are either reduces or eliminated/shifted. Just thinking out loud, but I want to keep thinking. In reply to: No I'm afraid I'm neither smart enough to analyize what I attempted to do at that level and have to date been unsuccessful in getting someone who is to help. I did what I did because I could. And your single unreflected shockwave is the one that worries me the most. Who knows, it might be the direct from say #2 hitting #8 at the same time the 1st reflected one from #6 hits #8 and because of the phase shift of the reflected they combine right on top of #8 as it's trying to fill - no air just good ole Murphy at work. I've seen this type of thing before and its a bear to figure out. Larry Edited by Larry M (05/10/02 11:32 AM) |
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Larry and others, Let me see if I can explain this. Please bear with me. Since there appears to be some air in the rail that cannot be accounted for could this be the cause. Everyone is talking about a harmonic imbalance in the fuel rail. There is some kind of a disturbance being created in either the fuel rail or some where around the split shot spill port. Follow me so far? We have an harmonic anomoly that occurs with every combustion stroke that we know causes damage and we currently add (are you ready for this) DC4 to correct it. If the walls in the water jacket are getting hammered by cavitation (harmonic anomoly) then why wouldn't the same cavitation have a similar affect on the fuel rail and spill port? If the pressure wave of cavitaion can force water away from the water jacket (and create air bubbles) why wouldn't it do the same thing inside the fuel rail and injector? Could this be the cause of the residule foam that TT mentioned? I find it hard to believe that the cavitation can be limited to just the water jacket. Thanks, Shane |
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First, let me qualify myself by saying that I absolutely do not know the final or best answer to the cackle problem. After reading Pat's comments in this thread however, I have to agree with him as much as I can. My work with fuel systems (professionally) dates from 1967 to the present. My experience is with fuel systems used on: (1) Reciprocating engines with (a) Carbureted or injected gasoline used in automotive, marine (hydroplanes) and aircraft, including National Air Race winners (as well as a few losers) (b) Natural or compressed gas including farm tractors and forklifts (c) Diesel fuel with horsepower ratings ranging from 5 to 6,000. (2) Turbine engines on ships, ground power, and aircraft (including alternative uses such as hydroplanes and army tanks) That said, I feel that I do have something to add to this very interesting discussion. Bubbles in the fuel line have always been referred to as "air". At least a half dozen varieties of "air". (Pat's, Hutches's etc) There are three types of bubbles possible in the fuel system. They are: (1) Actual atmospheric air that is drawn into the suction side of the fuel system, caused by leaks, allowing air to be pulled into the fuel line. Too much of this, and you wind up with no fuel at all. A little air can be compressed into a very small bubble depending on the pressure in the system after the supply pump, and when the pressure drops, these bubbles expand. (2) Vaporized or evaporated fuel. This is caused by the pressure in the fuel system dropping below the pressure required to keep the fuel in its liquid state, and can be caused by raising the temperature of the fuel to above the "boiling point" at a given pressure, or dropping the pressure of the fuel to less that the "boiling point" at a given temperature, or both. (Charles' and Dalton's laws) This can happen at a wide range of pressures and temperatures. (3) Exhaust gasses leaking into the injector and into the fuel system from the combustion chamber because of (a) wear at the needle and seat or (b) debris such as carbon or dirt holding the needle off of the seat. So far, no one has mentioned this as a source of "air", so I am now throwing another variable into the mix. Any one of these three will result in incomplete filling of the injector barrel when the plunger draws in the fuel from the fuel supply. This leads to a reduced amount of fuel in the barrel and will result in: (a) A delay in injection as the plunger compresses the bubble small enough that it either becomes a liquid again, or on up to the pressure required to open the needle valve, and is injected with the fuel into the combustion chamber and (b) A reduced quantity of fuel injected into the combustion chamber. The results are uneven combustion pressures, uneven firing, late timing, and a host of other effects that are observed as audible or inaudible noise (idle knock, “cackle” etc) and/or power loss. So, it seems to me that the solution (or at least reduce the effects) to the problem is to find a way to fill the barrel of the injector with a consistent volume of fuel. The mods to reduce suction line leakage helps with the atmospheric air drawn into the fuel system by repairing leaks and fixing an undersize inlet and suction line. The mods to reduce pressure spikes and harmonics in the supply fuel pressure line with regulators and accumulators all help as does removing entrained air bubbles by making a 'flow through" fuel system sending the air bubbles back to the tank. Reversing the direction of fuel supply flow so that the flow is from the #8 injector toward the earlier-firing #6 also helps, by providing fuel to the #8, before the #6 is charged, it reduces the effect of the pressure waves and resulting transient harmonics in the fuel supply line. Replacing an injector that has a worn or leaking tip will reduce or eliminate the exhaust gasses that are leaking back into the fuel system, using either the LL injector or any other injector replacement method (perhaps the “KL” fix for example?) When the correct one of these mods is used, it seem to reduce or eliminate the problem, if the mod addressed what the problem was on that system. Some fuel systems may have one, two or even three issues, so doing only one mod might not address the problem. Bottom line: The factory fuel system sucks (no pun intended). In my opinion, proper engineering at the factory in the first place should have found these problems, and with an engine in production this long, it should have been fixed by now by the manufacturer. All of these mods should have been done by the factory, not by us. They won't though. Remember the Pinto? When hit from behind, the fuel tank was torn open by a bolt head on the differential housing. They new about the problem, and even had a fix, but the $cost$ of the fix (less than $8 per vehicle) was expected to be more than the $cost$ of the lawsuits that would result from people being burnt to a crisp in the inevitable incidents. At least until the bad publicity and loss of good-will from the disclosure of the facts. Then - Poof - no more Pintos, and the fuel tanks are no longer unshielded or are now located in a more protected location. And now, after a few years, no one remembers, so we are all happy again. Same $cost$ benefit problem with this fuel system. The $cost$ of the fix exceeds the benefit, so nothing is done. By the way, aren’t they bringing out a new engine and truck? Perhaps they just want us to trade the “cackle pigs” in on a new truck and eliminate the problem that way...... Just my two cents worth. I have taken a lot of your time and most likely I have made a few folks upset, so I'll get off the soap box... for now. |
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Popperboy1, I think that is an excellent summary of the situation. I don't see how anyone could be upset. The only thing I would add is that some issues return loop despite the best intentions. Crown Vic police package is having some issues of note in respect to fuel tanks as we speak. And Mustang. But 60 mph crashes tend to bend things. |
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beantown, In reply to: |
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Larry, I agree. A complete in-depth look at the fuel system - flow - pressure - temperature - is where we need to find the actual problem. Your tools can do the job. The largest engines that I see have an external fuel supply line and an external return line, with the injectors in parallel between them. The system has suction strainers and filters, a fuel pre-heater, two pressure line filters, each injector has an inlet and outlet filter and a the system has a pressure retaining valve set at 60 PSI before the unused fuel is returned to the tank through a sight glass where we can see the return flow and detect bubbles at that time. The system uses 150 GPH at full speed (900 RPM) and returns at least that much to the tank. No amount of bubbling is tolerated in the fuel return line. We do not have idle knock or cackle. I live in the Chicago area. Drop me a private email if you want to visit while you are here. |
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Larry M I think TT did do fuel rail pressures. Go to the Fuel rail section. He has fuel temps, fuel pressures I think that are in relation to injector firing and two graphs that show the pressures at the injectors taken by sliding a test probe along the fuel rail by #6 and #8. I know he states that the data was taken by inserting a sensor in through the end rail plug. I tried to link to TT's site but I can not seem to get in. It is like it is shut down. If you can not get in to look at it, let me know, I have it on my computer and can email it to you. On Edit: I see you're retired Navy. What we need is one of your squid sonar buddies to help us out. (retired AF myself)
Bruce Edited by KB (05/10/02 02:06 PM) |
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KB, Thanks, I may have missed that - there is a lot out there to try and keep on them little 3x5 memory cards and will check it out. In fact now that you mention it, I do seem to remember something along those lines.
In reply to: Those are exactly the types on the R&D side that I was trying to get to help, but they do have more important things to attend to unfortunately. Those guys by simple looking at the stuff I was trying to do can tell if its one ant, two or what size cock roach is making noise walking - they are simply amazing. Oh well, we all try to help in what ever way we can. Larry |
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Larry, Are you looking for a Sonar man? How about one that was in the squid force will he do? See ya, Shane |
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beantown, No these are the PhD types that have designed and worked with acoustic/noise related R&D type projects for 20 plus years, there are only a handful out there and I have had the pleasure in times past of working with these unique individuals, but they are gems and they do their work with a single sensor worth what our entire vehicles cost. This is in no way is to say that the professional sonar types I think you are referring to aren't the professionals that I know they are, it's just a different scenario - it's the "been there done that" kind of thing. I wasn't looking for that kind of help which is unrealistic, but to check basically what I was doing because I appreciate the subtleties of what I was attempting to do, there are pitfalls and I was trying my best to do as good a job as I could. Larry |
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Pat, we discussed the low pressure inside the injector long ago in the cackle thread and I fully agree that that is happening. I also think you are spot on with the rest of your post. Have good trip. Dave |
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Beantown: Thanks for remembering that. I think Larry and I discussed this many moons ago, and it has generally been left out of the musings, but, yes, combustion shock wave could very well do just what you say. Unfortunately, can't think of a fuel additive that would be easily tested to investigate that thought. LJ: Some of your post is what I had just posted before you (didn't notice the time, might have been overlap). Popperboy: We had spoken about combustion chamber leaking into injector, I think when idssteve was still around, and that too has been sort of forgotten. What is different in the split shot is that a lack of filling can cause EARLY delivery of the main shot (the pilot shot is just skipped and the main shot banged in early), thus, in my theory, idle knock and destructive crank harmonic (supported by CP traces from TT). Larry (& KB): Yes, TT dragged FoMoCo probe down rails in front of fill ports and got temp and press data. THAT I will never forget. At the speed of recording, the data showed pretty wide swings (suspect much more going on, but higher speed required to acquire). If you want to get a "feel" for that, take a TT mod with flexible fuel line and wrap your hand around it with the truck idling - it is a real eye opener. Nothing wrong with the fuel system in these trucks, KL says???? I too am off for a couple of weeks, but going to work in New York, not holiday. Will have several days of TT and HX traveling to report on when I come back. Regards - Pat |
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Popperboy1 said ____________________________________________________________________ (3) Exhaust gasses leaking into the injector and into the fuel system from the combustion chamber because of (a) wear at the needle and seat or (b) debris such as carbon or dirt holding the needle off of the seat. So far, no one has mentioned this as a source of "air", so I am now throwing another variable into the mix. ____________________________________________________________________ I tossed this out long ago, see my post on this page. here Dave Edited by Grinder (05/10/02 11:09 PM) |
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In order for the gasses to enter the nozzel of the injector their pressure would have to exceed the pressure the fuel is under in order to reverse the flow, the minimum fuel pressure at needle in the nozzel is 4900 psi ( I think ) or 700 psi HP oil pressure X 7:1 ratio of the intensifier piston to plunger area, the MAXIMUM cylinder pressures TT recorded was 1600psi and that was a straight (non split shot ) injector installed and operating with split shot injection timing in the ecm. |
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No problem, Grinder. I just wanted to put it back on the table, as when we get bubbles in the fuel return sight glass on our locomotive engines, we "pop test" the injectors to see which one is leaking exhaust gasses back into the fuel system. It is the most common source of bubbles on our engines. As they say, your mileage may vary, and it might affect only 1 in a 1000 PSD's with the cackle. Other sources such as the close physical proximity of the 6 and 8 injectors and their relationship in the firing order I suspect is a big one, as is the stupid idea of dead ending the fuel rails by putting the fuel pressure regulator ahead of the filter instead of in the return line. Today is the first time I read about that the KL fix might be replacement injectors, and I know that when we rebuild an injector, it gets a new tip and needle valve, just to be on the safe side. |
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Popperboy 1, It was no problem, Just being a pain.
My reply to you was not worth the time it took me to find that stupid thing. I started on page 17.p
I thought you had some good points, got in a hurry and didn't put that in my reply. Sorry. Take care Dave |
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After following was has been going on for awhile but not knowing exactly what is being discussed I think I agree with LTJHAWK. What about air that is created in the injector when it fills? What about when the injector then goes to fire and the inlet check ball must seat? Wouldn't the air that was created in the injector be forced back out into the fuel rail? I think this is already addressed and this is why creating flow in the heads helps to solve the problem. The fuel cannot continue to exponentially foam and create lubricity problems which adventually fries the injectors. Actual air in the fuel supply verusus air that is brought out by the lowering of the pressure only compounds and speeds up the problem. Air in in the injector would delay the seating of the check ball and air would definitely be able to get around the check ball and back into the rail before it had time to seat. I believe I have read that pat riley said his truck ran better with lower fuel pressure, correct? I believe this is because their is not such a large pressure difference pressure difference created when the injector fills theirby releasing less entrained air. Just some thoughts. I have never had an injector out and apart so it's all just armchair expertise at this point so for those of you that have been getting your hands dirty, feel free to point out any flaws in my reasoning.
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beantown, In reply to: After carefully reading Pat's latest post, rereading yours which is this post is replying to, and this issue of air being released/created at/by/within the injector itself the fol are just some as Pat likes to called it musings which is not always bad, especially when you look at where we are today compared to say two/three months ago. This post is going to be long so those wanting to "muse along" get that cup of Joe and read on, it is a Saturday .
1. If you look back over my work making these freq plots I have always stated I think that these anomolies seem to be cylinder/injector/firing event related and that I have no way of pinpointing the actual source. Thus your combustion scenario falls into what I have found. 2. As far are trying to relate it to the water jacket cavitation as I said previously, as I understand it they are really two separate processes. The water jacket cavition is the result of the water being boiled off around the cylinder jackets simply because of heat. It is in no way any kind of harmonic anomoly like I might be seeing in my plots nor is it the result of a pressure wave pressure wave of cavitaion forcint water away from the water jacket and create air bubbles. The water jacket cavitation is strickly heat induced and the potential fuel rail cavitation is the result of these shockwave and/or hamonics.. Standing waves and harmoics are frequency and geometry induced situations. Think of these as the suspension bridge example that tears itself apart when the resonant freq is applied in some consistent manner. 3. Pat and a couple of others have mentioned this air/foam being created/released thru the action and pressure drops/variation of the injector itself. I've previously stated that I know little about these injectors and quite frankly don't care to know their particular ins and outs. Maybe I should, but what I view as the important things to consider is that they operate as designed. So proper filling is the parameter I look at. While I can easily envision the violent events at the injector potentially releasing air/foam I have a hard time jumping to the conclusion that this might be the ROOT cause of the problem since all injectors try to operate the same so why don't we not see probems in other cylinders - on the contrary everyone seems to have found that the problem is at #8 (TT CP imbalance, clyinder temp,physical damage,FORDs LL8 TSB). Not to dismiss the fact that this injector level air/foam phenomenon aggravates the overall situation, but to somehow point to it as the ROOT cause I could only seriously consider in one general scenario that I have come up with to date. Here are my armchair thoughts were the ROOT cause of cackle/knock could be the result of this injector level created/released air/foam either during filling, firing, spill port feedback, whatever and would expain why some cackle new, some never cackle, and some cakle at random times over the life of the vehicle. Assume for the purposes of "musing" that the quantity of this air/foam creation/release is related directly to the injector tolerances and wear somehow. Now I envison a subset of two processes that can cause an air related problem at #8 preventing proper filling. One scenario is if the geometry and flow is right which suprising enough would be rpm related(i.e. the physical flow rate of the fuel which goes from #6 to #8 is related to rpms). This fuel flow over #6 going towards #8 as #6 spurts out its quantity of air/foam into the fuel flow which I will call an air/foam packet. #6 does this consistently so we have a periodic introduction of these air/foam packets from #6 into the fuel flow going to it's neighbor nest door #8. Now #8 is also producing these air/foam packets but since #8 is at the dead end there is no #10 injector down stream for it to send it's air/foam packet to so it's stuck dealing with not only with what air/foam it might release/create, but a continuous and periodic rpm dependent onslaught of the moving and periodic air/foam packets in the fuel flow stream from it's upstream neighbor #6. If all conditons are right (fuel flow rate, volume of the #6 air/foam packet which is dependent on its manufacturing tolerances for a new vehicle or on its wear which is an additional delta that is mileage and random variable from vehicle to vehicle) this #6 air/foam packet arrives at #8 just as it's trying to fill and its air/foam packet combines with #8's and disrupts the proper fill of #8 enough so that you now you have cackle. In fact each injector up stream of the fuel flow would potentially be introducing varying quantities of these air/foam packets into the fuel stream which could effect its downstream neighbors. Just envision not a consistent and uniform fuel stream, but one with say little boxes of various volumes that are full of air/foam and not pure fuel. These boxes (i.e. air/foam packets) are continuously changing due to reabsorption, dispersion, moving around in the fuel stream due to rising up in the fuel stream over time, etc. etc. If this were the ROOT cause of cackle it would expain the randomness of its onset. Some right off the line, some never (maybe use of additives to lessen injector wear), some at various mileages (fuel lubricity, additives, chips, etc.). Vehicles suffering only this type of cackle which for reference purposes here I will call Cackle Basic might not suffer drastic mpg or performance problems, but would sure have the audible cackle symptons. The second scenario is basically an extension of scenario one and is the addition of the consequence of the dead end rail system and the location of #8 there and has to do with the constant build up of a "mega air/foam packet" continuously growing trapped at the end of the fuel rail past #8. Again as the engine warms up all the cylinders are contributing their various quantities of these air/foam packets into the fuel stream and varying amounts that are not pulled into other injectors downstream build up this "mega packet" at a sufficiently high rate that either the overspill continuously interfers with #8 filling at almost all rpms (i.e. the wide range of rpms for some cacklers) or its build up sufficiently to interfer with proper #8 filling only occurs over a limited range of rpms. I would call this condition Cackle Advanced. Furthermore, I could envision if #2 along with #4 are really bad offenders, both #4 and #6 might be filling, but with more air/foam in them than optimum. This along with a similar process of more air/foam in the rail on the passenger side could well make some audible cacklers have really poor mpg, flat spots, performance issues some of which could be rpm dependent. I would call some combination of these variables Complex Cackle which could occcur with both Cackle Basic and Cackle Advanced or simply by itself with the only effect being a small mpg or performance issue. Of course all these condtions after they have started occurring only get worse, especially for #8 due to the lack of lubricity which increase wear and all the other maladies when injectors are not being filled and operated as designed. Now that I've laid my "muses" of a potential injector related air caused Cackle out, let me for purposes of discussion look at these now 5 Cackle conditions - Cackle Basic, Cackle Advanced, Complex Cackle Basic, Complex Cackle Advanced, and Complex Cackle might be effected by the various mods being done. I won't go into detail on the Hutch mods since these are to prevent air pre pump which can only be good if they are effective in actually correcting a problem that exists. If there are no problems then they should have no effect on either a non cackler or a cackler. This can not be said of the TT regulator or the fixed orfice system, both of which provide flow thru the heads. I will also not consider the regulator effect on the fuel stream since we are not talking about pressure/shockwave induced cackle only injector air/foam induced cackle. There might well be some minor contibution in the simple filling process, but it is hard to say in a pure injector air/foam cackle situation what that is. However, the flow aspect of both the TT regulator and fixed orfice systme do play a big part both cackle and possibly a non cackler mpg wise. For non cacklers you will get denser and better fuel to the injectors, flush whatever amount of air/foam that is being produced out of the rails on both sides and these vehicles should see a slight mpg increase which is randomly dependent on which and how much each injector in both heads are producing these air/foam packets and diluting the energy densiy of the fuel that is being used by each injector - this would be especially true if these vehicles were suffering from Complex Cackle only. The combination are endless and the results I would expect vary greatly. What I find most interesting is how this flow scenario could effect the remaining 4 classes of cacklers. By eliminating completely this build up for the Cackle Advanced and Complex Cackle Advanced cases I would expect dramatic improvements to the point of completely in most cases removing cackle and for the Complex Cackle Advanced the rises of the 13 mpg "cacklers" to the 19mpg range or whatever. Now for the Complex Cackle Basic vehicles the results will vary from some improvement by reducing the effects of the Complex Cackle effect and maybe lessening the effects of teh Cackle Basic portion. How much would depend on what effect the increased fuel flow has on shifting the air/foam packet arrival time at #8 relative to it's filling which is the cause of Cackle Basic. I could envision it lessening, but not eliminating "cackle" to even completely curing it. This could explain the wildly varing degrees of success being reported by the various owners of the moded vehicles. With all this said, however, similiar scenarios can be developed if you assume that the shockwave and/or harmonics are the ROOT cause and these scenarios are even more complex since you now have to content not only with the shockwaves, harmonics from a pure pressure wave angle, but potential creation/production of air from them and I have seen this cylinder/injector/firing event related frequency and harmonic structure consistently in knocker/cacklers I have looked at and is absent in my non cackler, and have observed this freq/harmonic structure in my vehicle when I can tell it is knocking and within several minutes have notice the knock become inaudible with a dramatic change in the freq/harmonic plot. Thus my reason for at this point sticking with the shockwave/harmonic and not the Air as the ROOT cause because I have the data to support that position and non to support the alternative except that sufficient air can cause problems which is understandable, but as TT has noted Air as the source on a large scale noticeably affects no only #8, but #4 and #6 as well. There, enough is enough and I'll try and not say a whole lot more today, but sometimes I can't resist and after all this is all about sharing opinions and adding to the creative mind pool out there and since I took the time to type it, I have the right to post it.
As always JMHO and thoughts Larry |
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i always thought that the block pitting was caused by harmonics,i don't think its caused by high temps boiling the water away.the cly.are where the pitting occurs and they really don't get hot..the heat is in the heads and maybe in the top 1'' of the cyl..on lots of race engines the block is filled with concrete or some other filler to stiffen the block.this filler is poured in to within 1'' of the deck,with lots of drag racers filling the block completely.now,we all know that dragers only run a short time,but i have filled blocks on circle track race engines that race for 100 laps or so with no heat problems.i think all diesels except for 2 stroke detroits have this problem,and the reason the 2 strokes don't is because the cyl is only partly in water with the rest being part of the air box system..gas engines don't have this problem either...just sat. morning musings...please correct me if i'm wrong! |
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just had another thought,are these harmonics the reason the turbo bolts are always coming loose on these engines??i will admit i have not read the post about the bolts,but i never had them come loose on the 95 psd i had.....is there any relationship between cacklers and loose bolts? anybody??? |
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Personally I feel the loose Turbo Bolts are a result of the exhaust system harmonics, which cold be intensified by the cackle I suppose. I am a firm believer in a flex pipe to isolate the turbo from the rest of the exhaust. The next level PSD 6.0L will come factory with the flex PRE AND POST TURBO. Mmmmmmmm, think there was a problem FoMoCo? Funny I was told in May of 1999 by Navistar in a meeting that if I ordered a 2000 or newer that problem would be fixed by then. Yet another lie... |
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yes,flex would be a good plan!but the older psd did'nt have flex either with no bolt problems that i'm aware of,hell you could'nt get them out! |
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That is something that has puzzled my for 2 years now. Something was changed somewhere in the process from 97 to 99 trucks. The Turbo for one. |
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Not to get to far off the topic but when I boil water in a pan (some of my pans are really old!) I don't remember any pitting taking place in the bottom of the pan. I was to understand that the cavitation problem in the older engines was caused exclusively by acoustical cavitation of the coolant, a direct result of the flexing of the cylinder liners that took place because of the diesel ignition process. (the hard ignition knock) and has nothing to do with water boiling. If this were the case then merely adding a higher pressure cap to the system would have prevented cavitation. I am to understand that when a high frequency sound or concussion is applied to water that bubbles can be induced in water. The initial shock of the sound wave raises the pressure on the water then quickly lowers after the wave passes inducing bubbles which then quickly collapse, releasing energy and the whole process starts over again occuring each time the cylinder fires. The energy that is created when the bubbles collapse drills little holes in the cylinder liners. Similar to what takes place if a prop is to small for the amount of power being applied or if it is allowed to suck air. I am to understand that adding the SCA (not sure what the ingredients are) is a chemical that combines with iron or iron oxide to form a super hard surface on the cylinder liners that the cavitation cannot eat through. |
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Beagle 1 I wonder if the cackle has anything to do with the turbo bolts. The turbo is sitting right on top of #8. Maybe the pounding of that cylinder is what loosens the bolts. Iluvsteelies That was my understanding of what happens in the cooling system also. I wonder if the combination of the two (acoustical cavitation because of the diesel ignition process and the split-shot shockwave) is what is causing the problem. Larry M Do you have the frequency range that you saw when your van cackle or knocked? Maybe while your in the windy city, one of us here can dream up a way to absorb it or re-tune it to varify one way or the other if this is the ROOT cause. Bruce |
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Larry, I feel you are very close to a contributing factor of the problem when you speak about harmonics and shockwaves. I still feel the air theory is incorrect. Ghosts, entrained air or produced air is the wrong direction to go. My opinions of course. The last two days I have studied a bunch about the fuel delivery system in the pilot injected PSD. Unfortunantly, I cant buy the air theory even in part. The probelm is: 1) Shockwaves/harmonics in the rail 2) Hot fuel oil changing viscosity and lubricating qualities causing accellerated injector wear. 3) Hot fuel oil giving differing shot quantities of energy to some cylinders causing poor fuel economy, some cylinder pressure changes, and poor idle. The shockwave/harmonics portion I just added the last two days. When I started looking at your plots I originally felt some may have been fuel rail plots. This was not the case, but after I began to think about that possibility I backed off talking and started looking into it. I now firmly believe that shockwaves/harmonics play a part. I still cant disprove the hot fuel portion for the reasons stated above. Don~ |
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Don M, at what temperature and pressure does the split shot spill-over exit the injector? |
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Hutch, No exacts here, but close to 5K PSI, 345 BAR or 340 atmospheres. Temperature is not constant but would range from very cold to very hot. 30 degrees to 270 measured so far maybe higher. Why? Don~ |
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My fuel line theory AIR=BAD
