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After reading many posts about the Cackle issues, has anyone suggested the problem may be in the oil system?.. Many have said the problem is in the fuel system. Modifying the pick ups in the fuel tank, unsing a crossover, replacing injectors etc.. Some have noticed the Cackle noises as well as myself after changing the engine oil!..I have not changed my oil in about 2500 miles and have had no Idle knock or cackle noises..Since the fuel injectors are activated by oil pressure, has anyone suggested that maybe air is getting in the oil supply thereby not having sufficiant pressure to allow full pressure to activate #8 fuel injector..Last Summer, my cackle was so bad, it sounded like a rod knocking even inside the truck.. Now, it has gone totally away!  I still have a 'slight' idle knock, but it is very hard to hear...
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Did you change oil viscosity or brand to notice this change? Any other ideas why your cackle/knock is diminished now? youngster |
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I am using "Dello ".... Have not tried the others yet... |
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Cackle (usually more of a miss between 1500 and 2000 rpm) and idle knock are definitely fuel system related problems, and you are quite correct in considering the HPOP and its plumbing to be part of the fuel system. There has actually been quite a bit of work done on that count, and the immediate differences some find with the HX hose lets you know it plays a big part in the overall picture. The way the symptoms exists in some trucks and not others and come and go with time, oil changes, mods, etc. let you know the system is operating on the edge of critical design parameters. The huge level of production tolerances seem to be responsible for the random nature of infection with FIV (= Ford Intermittent Virus). Unfortunately, there is a lot of dissagreement on just which parameter is most critical. Pat |
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Any idea what you might have done differently for the cackle to go away? I just changed the oil in my van after a problem using Delvac. Switched back to Motorcraft and the knock went away. youngster |
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To add more confusion consider this: I did the fuel tank and pre-pump mods only about two years ago. All the cackle and knock went away and the truck ran like a dream and very quite. About a month ago I deciede to flush out the cooling system and put in new anti-freeze. Yes, I said cooling system. At the same time I changed the thermostat to a 203. As soon as I started the truck I noticed that it was louder. Thought it must be air pockets. Drove the truck awhile and kept a watch on the coolant level. Never needed to add. The cackle was back and kept getting worse. Now it is unbearable. I even took the 203 thermostat back out thinking that might be it. No help. By the way, I am using plain jane anti-freeze. I changed to 5w-40 syn oil and that seemed to help but cackle is still bad. I re-checked for air in the fuel by using a long clear line from the fuel filter drain back to the tank and connecting a battery to the fuel pump and watching the line. No air problems. I changed the fuel filter and checked the internals of the fuel filter housing. Seemed to help a little but no fix. I now have a by-pass regulator on order and will see if that will help. At least I can get the fuel pressure up and evacuate any air trappped in the fuel rails with that. I also plan to oreder the HX line to see if that helps. I think Pat Dolan hit the nail on the head. There is a marginal design here and it does not take much to throw things out of wack. Sorry for the long post, Bob |
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Uh oh! Pat Dolan is talking. I suggest you listen. I, along with many others consider Pat "The Man" when it comes to fuel issues. Glad to know your still around Pat. Thanks for all the work you put in. My truck and I thank you for making her run so quiet and smooth. I am sure it will make the world of difference in injector life too.  Look to the HX mods for some of your answers to this. I remember a member posting a link to his photo's where he had some trends of oil pressure fluctuations showing the difference that this mod makes and discussed this issue. Maybe one of the other members remembers his name. Would make for an easier search. Geno |
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I have the HX crossover on order. Would this be what you are talking about: Opps, that link does not take you to the HX graphs. Go to the link and click PRODUCTS and then drill down to Ford 7.3. Look for HX hose and go there. You will see the oil pressure graphs there. http://www.innovative-truck-products.com Bob Edited by nodine (12/23/03 06:51 AM) |
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During the last few month's of ownership with my 7.3 I had developed really bad cackle after doing some modifications and maintenance before a long trip. Part of the issue was air in my fuel due to the filter I had used. And I thought everything related to that, and the possible damage to my injectors. Some of it was injector issues not not to the full extent. At that time I had done a change over to Delvac 1. I previously tried other Dino and Synthetic oil brands, and was really to settle down for long term usage of a synthetic. The severe cackle issue continued for 10,000 miles and 2 Delvac changes. It was just there and bad. At this point I was about to trade in on my new 6.0 in a few weeks,but maintenance was due on the 7.3L. Rather then spend the money for Delvac 1 on a trade in, I replaced the oil with Rotella T. Like a switch, cackle gone. And it stayed that way for maybe 1,000 miles. When it came back, I replaced the oil again, just to see what was happening, and once again, no cackle. It could have been that the remaining Delvac 1 was causing some issues and needed to continue to be flushed out. Or that my HPOP was starting to have issues and needed whatever properties of fresh Rotella T. I had asked several other uses of Delvac 1 if they had issues, which they did not. Also asked a Mobil rep if thee were any batch issues out there, as my Delvac 1 supply came in one shipment. None he was aware of. But I did find out that Delvac 1 stays at about a 40ish oil weight, just doesn't thicken higher with cold. As ASEMechanic has noted in another thread, the control is based on a specific oil viscosity index. I'm sure we alter the characteristics of the fuel delivery with alternate oils, and I wish I knew what oil is used by International and Ford when they do their calibrations. With my 6.0L I really did not have any of the infamous Romp issues until I strayed from the factory then Rotella change to the latest Delo fill. Now have Romp. Viscosity, like size does matter  .
Using motor oil which should have a detergent (foaming) is really a bad idea for a hydraulic operation. This motor should have had two separate systems. Motor oil for normal motor oil functions, and a separate HPO system utilizing the best hydraulic fluids for high pressure, non-foaming characteristics for injector firing / control function. IMO. |
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So far, it's taken two oil changes to rid my van of the knock it had with the Delvac. Might take one more if it comes back at 1000 miles as you mentioned. What a difference oil makes in knock/cackle issues!!!! youngster |
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Jack: Detergency is not necessarily related in any way to surface tension (i.e. foam charactaristics). It's not like the refinery (actaully the blender) dumps in a box of Tide, or worse yet, a jug of Sunlight. Even then, those are surfactants to aqueous solutions, not necessarily hydrocarbon based ones. The principal surfactant for petro-lubes is Silicon, as in silicone, and just to show how strange it is, a few ppm may be used to make a very low foam test, whereas a few ppm more can change the whole batch into a milkshake. In all of our oil formulations, lube or hydraulic, we used the same anti-foam additive in about the same treat rate. The ability to transport entrained air and dissolved air is a normal charactaristic of fluids. It is not the foam on the surface that is the problem, except that entrained air that has risen to the surface will stay there as a bubble (which breaks in the normal course of release) for a long time - not necessarily reaching the oil pump (which picks up at the bottom). I am coming to believe that this is a problem with the HPOP, along with the observation from many that the pump just can't maintain performance required with age. Personally, I am a little embarrassed by Geno's accolades. My truck still doesn't run 100% - and is getting worse with age. I have developed a wicked part-throttle miss, which I am calling "cackle", but it clears up at full power. I am counting on the new wave of injectors about to hit the market to cure one problem, and THEN I will go on and do some things on my own to try to address the HPOP (including a variation on the HX). For now, I am not "the man", I am still "the victim". Pat |
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PAt, Was kind of hoping you would get sucked into describing the oil much better . I was falling back onto an old instruction of making sure to use a non-detergent oil if emergency makeup oil was needed in a hydraulic application.I just feel if I was going to use hydraulics for injector control, I would not be using the motor oil. Not only for it's normal lubricating property needs, but also it's need to carry debris as well as combustion byproducts that get by the rings. I would seek a kinder, friendlier environment for those little servo valves. And HPOP. Still using Delvac 1? |
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Pat, Is there an easy way to explain why different oils, with the same ratings make the engine react so differently? I read your post but after a 70 hour work week, my brain is a little fried. Am I correct is reading that silicone content could cause this regardless of oil brand? youngster |
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Pat, I have not been keeping up very well. What new injectors are about to hit the market? I am beginning to think I may need a few new injectors and would not want to change them if someting better is down the road. Also, what do the other engines out there using our type of injector do for high pressure oil. Does the Duramx use a simlar system? Bob |
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Quote: Peanut oil? Quote: Jack, I couldn't agree more. Not to mention how the engine oil properties change/degrade over time with contamination and shearing effects. That's asking an awful lot of an oil...any oil.  Quote: As we've discussed, I've had some issues with both versions (synthetic and regular) of Rotella that I really cannot explain either. Switching to Mobil Delvac 1300 Super 15w-40 made a noticable (in a positive way) difference. I have also considered going with Delvac 1 and the new Fleetguard bypass filter at the next oil change. Now I'm beginning to wonder if I really want to risk spending $100.00 on oil that will actually make it run worse, but wear better.  I have also noticed on my trips that fuel has a big effect on running issues and noise. With a 19 gallon tank, and fairly long day trips, I get to "sample" quite a bit of fuel from various sources within a relatively controlled "testing" day. What I mean is, it's not days between different fuels, it all occurs on the same day, with relatively unchanged conditions. I also notice a BIG change in engine performance and noise once the tank gets below 1/4 level. I have done the tank, pre pump, and regulator mods. What I feel is occuring, is that fuel is "sloshing" at lower fuel levels, and is causing the introduction of air into the system, either by the pickup assembly becoming exposed, or by the release of "entrained" air from all of the tossing and tumbling that the fuel must go through. Short of a Fuel Preporator type device, I can think of only two other solutions; a bladder tank, or foam fuel blocks like we used to use in the fuel cells of the road racing cars. I also have an injector (or two) that have been getting progressively worse as the miles roll up. Is this due to crappy Ford rebuilt injectors, or air? I tend to think (from what I've learned on here) that it's from the air in the fuel. The once quiet reman engine when new, has gotten very noisy from "cackle" lately. Now, to further confuse the issue, I added a Tymar H/X hose and did notice a slight improvement in the way that the engine ran. Slight though, nothing "ground breaking". Which to me means that there is no simple single solution to eliminate this. I have listened to quite a few Powerstrokes for comparison. In addition, I have also listened to quite a few Cummins engines. Something that I've noticed with the Cummins is that they have a higher pitched "pinging" or "cackle" noise at idle when in neutral and in "Drive", but it seems to disappear or fade as they rev up under load. (This is from driving alongside of them with my window down, so I can't really say what they sound like from inside of the vehicle) I have also listened to quite a few "Class 8" tractor/trailer trucks that do this same thing. It's a noise that I never associated to diesel engines before owning, learning about, and working (alot) on this Powerstroke. And...I've been around engines (both gas and diesel) all of my life. Could it be that with the reduction of Cetane rating and sulfer over the last 5-10 years, we are experiencing the "pinging" of late model computer controlled diesels that was so common on the early computer controlled gas engine cars of the early eighties? Could it be that with all of the variables involved, that these engines are just more susceptible to it than most? Consider these variables: * Normal injector wear and degradation over time. * Carbon build up in the cumbustion chamber, and the associated rise in compression ratio. * Fuel quality and the variation of that. * Sensor degradation over time. * Limited PCM monitors and controls, and the associated speed at which these functions take place. * The design of the injection system itself. If you think back to the cars of the late seventies and early eighties, nothing would cure them short of an entire fuel/ignition system rework. Are we trying to fix something that really just can't be fixed, given what we have to deal with? Will these diesels go down in history as being plagued with similar infamous issues, just like the cars from the late seventies and early eighties did. I'm beginning to think that they will. I'm thinking that we're Ford's and International's "learning curve" for electronically controlled diesels. Is that really what I bought into?  Erick |
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Pat, Your contributions to this topic have been top notch to say the least. Thanks to you, Hutch, and a few others ( I can't name them right off hand) my truck is the better for it. No one is perfect. I just want others who are new to know that people like you are what makes this site go from good to great. Again thanks. This thread is getting really deep. I would have to pull out the old physics and chemisty books to keep up. I just wish that someone with a lot of money could do some experiments that reflect some answers to all these theories. If I had it, I would do it. But alas I am just a poor boy trying to enjoy what I have. I do have one observation/questions to offer. Why is it so easy for Cummins or Duramax to produce so much more power without all these upgrades we must do to our beloved Powerstrokes? Are these trucks just too complicated or what? I don't know. But I sure hope we figure it out. |
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Complicated fuel system, sh$ty fuel lines and under powered hpop. |
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Complication and inefficient..not that I'm an engineer or anything but our fuel system picks up about as much air as it does fuel. Then our fuel rails are filled with oil rather than fuel. OK....fine, but then we have a HPOP that can't deliver the pressure needed to run our equiptment right. (Whatever your definition of right is.)Even if the pressure would stay constant, that would be something, but ours actually drops as you "need" it. |
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Now I see what your saying. You got ta give it to me straight. I have been working 22 out of the past 25 days. I am on brain burn out. So common rail fuel systems and a good mechanical oil pump is the ticket? |
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BINGO!!!!!!!!!!!!!!!!!!!!!!!!! It is..especially if your lookin' for hugh hp numbers.
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Too many things to keep straight, but let's try. Jack: I still use Delvac 1, in fact, I now use it in everything in the yard (gas and diesel) - except racing Hondas (go kart engines - we use 0W-30 in splash lube at 6,500 rpm on 3,600 rpm engines). I agree that USED motor oil would (should) be a last resort for running the injectors, but there gets to be a matter of practicality. Even using a dedicated hydraulic circuit, you would still end up with swarf in the stream that needed to be filtered out. Yougster: I wish I could explain how and why different oils could give the different reported results. If I could do that, I could probably suggest the way to fix the injectors. Bob: I think there are 3 suppliers about to be in the market with new injector mods, and at least one to do the HPOP. I can't honestly say I can remember what system the D-Max is using, but it is NOT hydraulic actuation. Cat uses our injectors (actually, they are CAT's injectors) on a lot of engines, as does IHC/Navistar. Erick (and everyone): You mention several things that are close to the heart of the actual problem. As things wear, or as production tolerances vary, the system steps accross a line in the sand where it doesn't work well. This is due to the design philosphy at CAT/Nav that ASSUMES a bunch of things are right, measures a few others, and the sends a time signal and an oil pressure signal to the engine. Now, on the pressure front, there is a feedback loop that should take care of SOME HPOP performance degredation (ASEMech/Bill - please comment if you are handy) up to a limit, but the time signal goes out to the injector and just ASSUMES that the fuel is being delivered. When you consider all of the possibility of air entrainment, dissolved air coming out of solution, leaking check valves, incomplete injector filling (on the return stroke) on the fuel side, and add some of those same problems on the oil side, and you can see that there are a lot of things that could NOT be happening when the system is assuming that they are within the time signal. The air thing is eliminated when you go to common rail, since the system pressure remains high enough that you can assume (fairly safely) that you always have nothing but the assumed volume of liquid within the opening time. I like the idea of a closed loop further down the system, like the old (up to 2003) low HP VW tdi. In that system, which uses the old Bosch rotary pump and a computer controlled rack and timing, most of the variables are taken care of by putting a sensor on #3 injector to see when the fuel pressure has risen enough to actually lift the needle off the seat and deliver fuel. Geno: see Joediesel and Thuglike replies to you. Yes, common rail has some distinct advantages. All of which may be moot point. It looks like the new piezo-electric injectors coming from Europe may hike the whole game up to a higher level (can do as many as 9 distinct shots during a single high-speed cycle and deliver higher effective pressure to the injector tip). Remember that one of the keys to the supposed advantage of the HEUI was its rate-shaping ability. Truth is, it would only do so if it worked exactly as planned, and it doesn't. Pat |
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I'm catching on now. I'll ponder it further. By the way, I have always used Delvac 1300 super for oil. Seems quieter than Rotella. But my truck has always run quieter than most from day 1 compared to others. Don't know why. It almost sounds like a gas burner when in the cab even during acceleration after the mods without any sound deadening material used. |
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Quote: Is the ping you describe the same as a cackle? I think the disappearing act would be a matter of the dynamics of sound rather than the elimination of the sound creation. Have you ever seen a bandpass box? Sound can eliminate itself. I get to listen to both cummins and psd and idis almost daily. I think the cummins sounds weird at low rpms under load. Like a chain being dragged across a metal bar rapidly. Almost like a gasser when suffering detonation. A diesel runs on detonation so I ignore it best I can. I havent been around the old diesels but know the injection pressures were much lower. Including the idis. Id say the idi is far quieter than mine. I believe the loud ping you describe is by much better atomised fuel cumbusting much more rapidly. This causes a much sharper rise in pressure within the cylinder than the older type injection systems. Epa made higher injection pressures a must. Even the 12v seems much quieter to me or not as pingy. These newest injections systems were designed with noise in mind. Thats one of the reasons why they split the injection event. I myself like the noise, most of the time. The fact that all three now use pilot injection makes me think that many people are seriously turned off by the noise. I heard a 6.0 yesterday that sounded about as loud as the 7.3. I hadnt seen this firsthand so I was suprised by it. He was on the move. I wanted to ask him if he had the flash done that eliminated the pilot injection. Wouldnt have been able to catch up to him. |
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Actually The Pinging is the Injector Missfiring,For whatever reason its Not filling properly and Not delivering Fuel correctly when this happens,IMO Possible causes may be Air Intrusion ,Harmonics from Injector spitback creating havoc with fuel flow,And who knows what else is going on in The HP oil rails But there more than likely is issues with it too that may be contributing to the problem.But this is all a guess on my part and I have No proof on any of this,.But Not ALL tks exibit the "Rattle" or Cackle.I think the tolerances on flow rates for the HP Pump,and Injectors are so poorly engineered that this is the reason some tks run properly and some dont.This has all been hashed out many times before.IMO The HEVI system is troublesome Expensive and Rarely works right,At least in the case of Ford and These PSD'S.Too much to go wrong and a common rail setup would be the ticket for these motors and I think Ford and International have finally given up and you will see it on the 6.0 in the near future. |
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Quote: And I've had the opportunity to experience a few of those vehicles over the years. And it absolutely floors me. But they are few and far between. They are stock and the sound is between a typical PSD and big block gasser from the 60's. I'll throw cam timing into the mix of issues as I once interviewed an engineer who worked with an OE cam supplier, and he went off for 1/2 hour on his pet peeve of this subject, despite all of the sophisticated computer controls. |
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How is the HPOP underpowered? Can it be turned up? Can we "shim the regulator" in it too? youngster |
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People are working on it. You can do nothing in the driveway to help it. |
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Quote: That great post "PCM Basics 101" by ASEMechanic mentioned a vicosity table. A point that was not lost on LarryM. This got me to thinking of the relationship of different weights and brands of oils, and resulting performance. The table must be pretty generic and the best guess by Ford. The whole deal runs off the information supplied by the Oil Temp Sensor. Seems to me that one might put a Trim Potentiometer in the oil sensor circuit (ala the 10K mod). That may allow ajustment for sensor and viscosity variances. Anyone got some spare time on their hands?? Al |
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Operating engine oil temps should stay fairly close in to the 100 C or 212F range, where the viscosity for most recommended oils would be in the SAE 40 grade RANGE (keep in mind, that is a very wide range indeed). Why this is significant is that this is the temp at which the second viscosity number is measured, so regardless of the VI (viscosity index) of the oil, they are all within grade at that temp. Also, they mostly fall into the 5W or 15W range at 40C (rating temp for the first SAE grade number), so will exhibit more-or-less the same VI between those two temps. That is why I am truly puzzled at the range of behaviour reported with respect to different oils. Where I would expect to see some big differences is during warmup when the oil is below 100F and the natural VI of the base stock (MUCH higher for synths) would have some big differences. I haven't seen Bill's post on PCM 101, and will do a search. Thanks for the referrence. And, MERRY CHRISTMAS TO ALL!!!!!! Pat |
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The wierd thing is that when I last switched from Delvac 15W-40 to Delvac 1 5W-40 synthetic, my own truck got much quieter and I've been very pleased with the results of subsequent oil tests. There just doesn't seem to be any consistency in our oil results re: engine noise and cackle, some have reported improvement changig *to* Delvac , others here are reporting apparent improvements changing *from* Delvac, but changing oil and hearing a difference seems to be a constant. Could it be related to the oil filters? Air in the oil? Foaming? Depleted anti-foam additives? Oil viscosity vs. temperature? One factor I've pretty much proven to myself is FUEL type and quality greatly affects the cackling sound in my own truck. Much more so than oil. I've become convinced that higher cetane and lubricity = quieter engine. I can add 5 gallons of biodiesel to my fuel and the engine gets markedly quieter. If I add 10 or more gallons it gets almost silent like a gasser. I usually try to run straight #2 with additives (in the winter), but if I fill up with the crummy 30% kerosene- 70% #2 winter blend, the truck gets noisier, instantly. I think Erick here also mentioned fuel quality. I once mentioned my engine noise observations and where I fueled to someone I know that drives a tanker and delivers fuel to truck stops. He confirmed that the places whose fuel gave me the noisiest engine were notorous for selling crummy fuel- second rate stuff contaminated with gasoline, maybe jet fuel, for example. They buy it cheap and hope it gets diluted in their undergound tanks so no one will notice. And this is from truck stops that have big national brand signs in front, not corner markets. They're not above buying a half tanker of fly-by-night fuel for cheap. OTOH, outfits like Flying J sell top-quality fuel. And a lot of us have noticed that. Mexico has a higher minimum mandatory cetane level in their country than we do here. Did you all know that? The US Federal standard for highwway diesel is 40, Mexico's is 48, and Europe's 2001 standard is a minuimum cetane number of 51. They sell the worst quality diesel fuel in the world right here in the USA. No wonder our trucks sometimes run like crap! The stuff just won't ignite under compression, effectively retarding our injection timing. And where's the state fuel inspectors and the cetane stickers on the diesel pumps? |
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Sorry Pat, I should have posted a link to PCM Basics 101. I see a link to the viscosity tables have be posted in that thread. If I am reading them correctly, it looks like the ejectors are backed off a bit with higher oil temps and low power requirements. May explain why these things tend to cackle in the 1700 RPM range and at idle after a hard run. Hope everyone has a safe and happy Holiday. |
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Allow me to throw another issue into the mix: elevation. I am from Denver but am currently in Savannah, GA. In other words, sea level. My truck now sounds(at idle) like a good running 6.0 but runs like a scalded ape. I do believe my PM rods are at risk at this elevation. I dynoed 360 in Denver and it feels like 25% above that here. At 6000' it knocks, misses, and has less power (expected). Air quality and density is a given but what effect can this have on fuel delivery? DZ |
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C-C: Don't know how I missed the thread in the first place, but thank you for the link. Season's Greetings - Pat |
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This thread's moving right along huh? Some good points and observations too.  Quote: BigDaddyT, You know, that's a good question. I don't really know if it's the same or not. That's what it sounds like to me anyway, and that's what I call cackle. Others may describe it differently. Still others may be hearing something else entirely, and describing it as cackle. There have been .wav files of cackle and idle knock on here before, but it's sometimes difficult to hear it the same way on the computer speakers as you do from inside the truck cab. Idle knock's pretty easy - sounds like a rod knock and gets your attention pretty quickly, so I don't think that there's much confusion there. Quote: Yup, or a chain being used in a pulley setup, like in a chain hoist where you can hear the individual links "clinking". I think that the Cummins sounds like it has cackle too. Detonation/Pinging - same type of noise. Quote: Could be, but I'll tell you this; my (2nd) Ford remanufactured engine ran perfectly (and I mean perfectly) for about 1500 miles, then began to lightly cackle with the associated vibration. This always seems to happen when a injector is starting to fail. There is a vibration that you can feel in the steering column, and in the seat when an injector begins to go south. Feels like a rough road surface or a slightly out of balance wheel. I have gotten accustomed to listening to it, and "feeling" it. The new reman now has about 10K on it, and it cackles badly now. Gets worse as the miles accumulate. When I do the silly Ford Cylinder Contribution Test, I occasionally get a "Cylinder 8 balance/contribution fault". Most of the time it passes the test with no problems found.  My girlfriend even commented about it when she rode to a dealership with me last week: "God, no wonder you start falling asleep on the way home after an auction - this seat feels like a vibrating massage chair. Does your seat feel like that?" ("Yeah") "Why does it do that?" ("It has a bad injector.") "Again?" ( [sigh] "Yeah") "Why do they keep going bad" ("Because it's a Powerstroke engine" [while shaking head]) "You need to get rid of this truck, and get something that you don't have to fix all the time". ("Yeah.")  This is from someone that doesn't even know where the oil, coolant, or windshield washer fluid goes in her own car....but maybe she has a point. Erick |
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Truck from about 1k on had a bad cackle. At 12k-13k did the "Hutch" tank mods. All was quiet for about 8k-10k more. Cackle came back for about 2k-3k and then #8 injector went bad. That was replaced and all has been quiet since. When this thing cackled, everything affected the noise. Oil brand, brand of fuel oil, and outside temp. It was horrible. Now, nothing makes a difference. Oil brand, brand of fuel or outside temp make no difference in the noise the engine make. It is just a good normal sounding diesel. If the engine is cold, and I have the flip on a high setting, it will make more noise but it is no where near what the old cackle was. I find it very interesting that this topic use to dominate the forum in the pre "Hutch" mod era, and its hardly mentioned any more. Have a Merry Christmas everyone. Jim |
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Quote: But then what would we do with all our spare time!  Bob |
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Heres what my brain has summarized through this site, driving/riding in other peoples trucks and of course, experience with my own truck. Air in the fuel leads to an incomplete fill of the injector or gives the fuel compressibility. This means that either not enough fuel is injected during the preshot to ignite or that the injector piston moves down so fast that their is not enough delay between the pre and main shots for the fuel to light. This leads to intermittent retarded firing of that particular cylinder which leads to the midrange surge and more combustion noise that you would call cackle. Fuel can also cause it. The cetane rating affects how easily the fuel burns or ignites. Fuel that is harder to ignite will also lead to a longer lag time. This means that by the time the pre-shot has had a chance to start burning, the injector is already into the second shot. Oil viscosity variations or air in the oil can also cause it. Even though the table in the pcm is supposed to compensate for it. The signal that the pcm is recieving as to what the oil pressure is, is not necessarily whats present at each injector.(especially if air was in the oil) If some of the injectors are getting slightly higher oil pressure than the rest this will also lead to cackle. High oil pressure causes the injector to operate too fast so once again their is not enough lag time between the pre and main shots which again will lead to more noise, intermittent surging and a possible loss of fuel economy. (also, I think they had a reflash for cackled that involved installed a LL8 i think that reflash lowered the icp in the rpm range we are talking about, hence the reason some complained of a loss of power and fuel economy with the flash and injector?) Injector wear can also cause it. Obviously if the injector scuffs, fuel can leak around the piston. This again would also mean that the injector would operate to quickly or not inject enough fuel on the pre-shot or have to much lag time and again lead to a possible intermittent surge or cackle. Also gonna add. Thinner fuel is more likely leak around a worn injector. So any additives that thin fuel will also increase the chance of cackle. And last but not least, engine operating temp. A colder engine will cackle more because of once again, the pre-shot takes longer to light. 
I also notice more engine noise below 1/4 of tank and intermittent rough idle. I also notice more noise when the just before it comes time for an oil change. I don't pay attention to fuel to much, I fill up at the same stations every time.
I would describe "cackle" as a pingy sound at about 1700-1900 rpm combined with what "feels" like a miss/surging. Also, you have to realize that once the oil pressure (ICP) is high enough these injectors work like single shots anyway. So it would be impossible for your truck to cackle high RPM. At low RPM's the oil pressure is low enough so the injection rate is much slower so the engine would be much less likely to be sensitive to any of the factors I mentioned above. Seems the ICP is just right at about 1700 to 2000 rpm for cackle to occur. Lots of holes in what I said, obviously I can't mention everything and how I think it all correlates. And I got to open presents now. What ya guys think??
Oh and also, while the brains of this site are on this thread I also noticed that someone has started a new thread about it too......Why does the engine fire up faster when there is air in the fuel? When its nice and full the engine kinda strains to life but when I can audibly here the pump sucking air, usually below a 1/4 tank you barely have to crank it and it starts (fires up with authority too)...Any ideas? I also know some of the regulator kits are designed to bleed off fuel pressure to give you faster starting. ???????? Edited to add some more ideas and correct a few spelling and grammar errors. 
Edited by Iluvsteelies (12/26/03 08:04 PM) |
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This is sounding like a realistic theory now. I've noticed with my truck that it gets really noisy when my tank gets to a 1/4 or less. So much so that I religiously fill it before I get there. Even my wife notices if I let it get low on fuel. I did all the fuel system mods while my truck still was new (1k-1.5k miles) including losing the LL injector. It's now got 28k and runs great with no hint of cackle. I'm inclined to think that I prevented a lot of injector damage/wear by fixing the air problems early. FWIW, I bet that most of the bad cacklers would be cured with a new set of injectors and complete fuel system mods. I bet this had a lot to do with the supposed Lux fix, he probably cured cackle as a by-product of re-manufacturing the injectors. Joe What ever happened to him anyway?
Edited by jasilva (12/25/03 03:31 PM) |
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Quote: EXCELLENT summary, Steelie! Thanks for laying it all down in a nice, neat manner. Being a combination of factors explains why people have had inconsistent results with the different mods out there. As I previously mentioned here, I can almost guess the cetane rating of my fuel based on my truck's mid-RPM cackling and I have also experienced an increase in noise when due for an oil change and an immediate reduction in cackling after putting fresh oil in. |
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If my .02 is worth anything to you, I'd give you an A+ for that post as it relates to how the injectors act/react to different changes in their operating environment. Because of the issues in the past with supposed cackle fixes and injectors, I'm leary of saying very much about what I think on this subject. However, if you have a truck with cackle and failed inejectors, I'm very interested in doing a dissection on them if you care to send them to me. (And you might get it back fixed.) |
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Iluvsteelies, I liked it so much that I printed it out. Bob |
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Quote: Jonathan, Please do comment on this. I have talked with a few people about the R&D ( "beta" sounds stupid, it's not software, it's an injector, dammit  ) KL injectors, and have waited (and waited, and waited, and waited...... ) for the findings on the actual production KL injectors that are supposed to really "fix" this problem. All kinds of secrets....not much actual proof. You, on the other hand, have been more than open and honest with me every time we've talked. No secrets, admitted where you had made mistakes in the past, and admitted what you didn't know the answers to. Very honorable. Certainly something that you can't say about some of the other sponsors on here.  I think that you have probably done more true research on these injectors than anyone else rebuilding them. I would not hesitate for a minute to do business with you. I think that you're one of the most honest and open vendors that I have ever spoken with. Not a pitch. My opinion. When I identify my problem injector(s), they're on their way to you for failure analysis. Damn, kinda wanted to take one apart too. Erick |
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Swamp my issues with that pop-up incident aside... Just get those big injectors worked out and price them about 1/4 to 1/3rd less than diesel innovations so I can obtain a set will ya? How about 5 grand for a set of injectors, ball bearing turbo and flip chip calibrated to the works eh?  He he... I think Kims injectors probably just increased the volume of the injector above the spill port or moved the ports further down the barrel to give you a more signifigant pre-shot...Or am I off base on this one? |
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Iluvsteelies, Good post. Well summed up. I'll throw in some of my observations for comparison on some of your points. Quote: I've noticed the "fuel effect" too. One other thing that I have noticed on my truck is that fuel "conditioners" never seem to actually add any power. If anything, they seem to make the engine more sluggish. Kinda like using high octane fuel in an engine that really doesn't need it. The net effect is retarded timing. Cackle does seem to be reduced during all of this. Something else that I've often wondered about is the viscosity of the fuel. Probably a perfect question for Pat, but it would seem that the summer blend fuels would be "heavier" than the winterized fuels. In my experience, the summer fuel produces less cackle. (I have had alot of problems with the engine(s) in my truck over the last 2 years though, so I really can't say how accurate that observation is. ) It would make sense though, especially if injector piston/bore scuffing was causing leakage past the piston. Quote: This could very well be why different oils make such a dramatic difference. Maybe there are a couple of different oil issues affecting the oil system. Maybe the higher viscosity oils help when there's a slight air leak in the supply side, and the additive packages in other oils help when there's an oil cavitation problem. Quote: I thought that the re-flash was so that the LL wasn't flagged as a bad injector when performing the silly CCT. It's so vague (the CCT) though, that I find it hard to believe that it would pick up the difference between a regular injector and a Long Lead. Quote: I can feel a difference in mine before and after an oil change too. Same with the 1/4 tank or less, and I've done all the (now commonplace) mods. I'm really surprised that JimF hasn't jumped in here. He has had excellent results with the Fuel Preporator. I'm now thinking that you have 2 choices with this HEUI injection system when it comes to fuel; either never allow your fuel tank to go below 1/4 tank (not really practical), or install a Fuel Preporator or similar device, to keep aerated fuel from ever getting to the injectors. Quote: I've noticed people mention this RPM range before. I guess mine is sort of an "odd duck" in that it's a 550 rollback tow truck. It's got a 5.33:1 (I think) rear axle ratio, and at 70 mph I'm taching about 2650 - 2700 RPM. It cackles constantly while cruising on flat roadway at 50 - 60mph which (If I remember correctly) is at about 2400 - 2500 RPM. Maybe the PCM strategy at light (cruise) throttle is such that the ICP pressures are similar at this rpm on my truck, to what you're experiencing at lower RPM's on a truck that is geared differently. Quote: I've kinda noticed this too, and remember reading about it in some of the old original regulator threads, but really haven't given it too much thought. Thinking about it again, I'm wondering if aerated fuel provides a sort of "fringe benefit" in that it is more atomized as it leaves the injector nozzle. Sorta like an aerosol spray can as it is running out of liquid. More of a mist than a spray. Maybe this is making the engine "light off" easier, but then delivering a lower quantity shot of fuel once running which is showing up as the problems we're describing. Erick |
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Quote: The situation you have described caused by an incomplete fill will lead to intermittent advanced firing, not retarded. It is more audible at the peak torque RPM range because that is when the most fuel per rotation is being injected. |
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Eric, I'll accept your invitation to talk. I have a set of Kim Lux injectors in my shop that are about a year old. I will say that the workmanship in the injectors is top quality, but the ideas are off-the-wall. Because Kim is very concerned about protecting the "proprietary information" of his injectors, I will respect that and not say exactly what the mods are, but I will say I do not believe for one moment that they can improve the functioning of the injector, although they could change things inside the injector enough to mask the real problems. The injectors were sent to me by a forum member who bought them trying to solve his cackle problems, but he removed them because of excessive smoke. The smoke was partly because the injectors have nozzles on them that are capable of flowing some 500% more than stock, although the injector flow capacity has not been increased at all. My thoughts on the cackle/idle knock are as follows: The 94-97 trucks don't have this problem: The two most significant differences that could effect this is they have single shot injectors and a flow-through or return-type fuel system. Many owners of the 99+ models have reduced or eliminated the problems by increasing fuel pressure and/or reducing fuel system restrictions. Now, remember that I didn't go to Injector University. I'm a gear head who has spent every free minute, day and night, for the last year and a half studying every aspect of how the injector works, why it works, how each and every part acts, reacts and interrelates to each and every other part. Based on this, I think there are 2 basic problems with the split shot injector: First, the fuel inlet in the stop plate and fuel plate are too restrictive and can prevent the injectors from refilling properly with fuel, and cause vacuum or low pressure conditions while refilling, leading to the release of entrained air. Second, during the bypass period between the pilot and main injection events, some 30-40 mm^3 of fuel is ejected from the plunger and barrel back into the inside of the injector body, which in turn opens into the fuel cavity of the injector cup and fuel rail. When this fuel is ejected, it causes a shock wave in the entire fuel portion of the cylinder head. I doubt this could be seen without some very sensitive pressure transducers, because it lasts for only a fraction of a millisecond, say 1/4 of 1/1000 second or less. Since fuel is basicly incompressible, this pressure really can't go anywhere. If you've ever seen an injector, there are 4 fuel inlet ports in the lower body. The bypass port in the barrel is just inside these ports, and on some injectors it is directly aligned with the inlets, so the bypassed fuel is shot directly into the fuel rail, whereas on other injectors the fuel would by directed against the inside of the injector body. As far as the difference between AD and AE injectors, I can't find any at all. Whereas the differences between the AA, AB, AC and AD injectors are instantly and easily identifieable, whatever it is between the AD and AE are not. I am quite willing to give credit to the explanation that the AE's simply flowed to one side (probably the high side) of the acceptable. range during testing in the factory. |
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Quote: Yes, the FP cured all of my increased engine noise as the fuel level went down. Just too many variables in this lousy fuel system IMO. Like I said in an earlier thread, it's hard to know where to start "fixing" this system. BTW, I liked Iluvsteelies post also. From Swamp Donkey's post: Quote: I totally believe that also. These injectors are yet another source of the air/fuel flashing problems in our system, IMO. That's why I say that these injectors should be called "agitators". Air in the fuel rail was talked about on this site back in 1999. One of the experiments (you may remember) that idssteve did was to provide a bleed point from the rear of the drivers head and then to lift the rear end of a truck with a fork lift so the air could escape. The engine quieted down immediately. At the time, no one knew for sure where all of that air was coming from. Here's the post from May 2000 from idssteve: Quote: That was a very exciting post at the time! That post is the basis for how I have my system plumbed now. If you want to read the whole thread, which is pretty good, go to the archives and search for "Cackle Whoopped!!!!!!!!!…….???" in the "1999-Up Engine and Drivetrain (12/99-11/01)" section. |
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Jim, Glad you're in on this. Since you brought it up, how is your system plumbed? Mine is plumbed like this: Fuel comes from a slightly larger Bosch pump without a check valve, and enters the stock valley filter in the stock location. Leaves the stock OE filter assembly, and travels through the stock fuel lines to the stock inlet locations at the heads. (Check valves/pulse dampeners are still in place - may come out this weekend.) Leaves the heads (passenger side front & drivers side rear) through Vibra-lok fittings, to 1/4 inch hard (brake line) tubing, to Vibra-lok fittings at each side of the aftermarket Aeromotive regulator. Restrictors (.063") installed in each fitting at Aeromotive regulator. Outlet of Aeromotive regulator plumbed into the stock return, with the return from the OE valley filter housing still in place, but shimmed to 100+ psi. Stock OE regulator pintle bleed hole opened up to .014" - .015" to allow continued air bleeding from stock OE filter housing. Have set the pressures between 64psi -72psi with little change other than a louder idle knock at higher pressures. Erick |
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Quote: That's interesting. What happens to the idle knock if you drop the pressures to 55-64psi? Does the idle knock disappear alltogether? I'm no expert here, but a question has just been raised in my head: is it possible that higher fuel pressures allow the release of still more entrained air? Consider the fuel rail itself (the cast one, inside the head). It was mentioned that it is only machined part way in -- with a rough casting surface further inside the heads. A rough casting should cause a great deal of turbulence. Has anyone thought to have them polished? Remove the heads and have the fuel rail ExtrudeHoned. It would polish the entire rail and almost entirely eliminate the rail as a source of air intrusion. Don't know if I'm talking out of my backside here or not -- just thinking out loud. youngster |
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Swamp Donkey, Ponder on this one please. Currently have 33K and have had the complete fuel system mod(single loop with return) installed since around 500 miles with the exception of changing out the LL injector. I am running with 80psi fuel pressure. I have an engine that purrs beautifully when it starts up until the engine oil temp hits about 110°(est) then I get a slight idle knock in my opinion. No cackle issues at higher RPM's. Why the knock after the oil warms up? I have checked and cannot find any air bubbles prior to the fuel pump. |
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Swamp, are you saying that you see no difference in the location of the annular ring between the AD and AE injectors that you have dissected? Are these remans or originals, maybe both? |
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Quote: youngster, Don't know. I never really set it lower than about (+/- 1psi) 64psi. At 64 psi the idle knock would come and go occasionally, but it really wasn't all that loud. Quote: I'm no expert in that department either, but from what I've learned about diesel fuel from Pat, Larry, Jack, and some others, increased fuel pressure seems to help prevent the release of entrained air, and/or causes it to be put back into suspension within the fuel. Quote: In a dead head fuel system I don't think it really makes any (much?) difference, since the fuel isn't really moving any faster than the injectors are delivering it. I can see your point in an unrestricted return system though. If I remember correctly, ExtrudeHoning was mentioned in some of the old cackle threads. (Not sure though, you'd have to ask the guys I mentioned above.) The valley fuel filter is rated at 2 microns for the protection of the injectors. Rapid wear and piston/barrel scuffing occurs at something like 6 - 8 microns. You'd have to be real certain that you got all of the ExtrudeHone abrasive out after it was done. I know that even if it did reduce/eliminate the cackle, I probably wouldn't do it on my truck, just because I'm not willing to R&R the heads, disassemble and reassemble them for this cackle issue. Not to mention the cost of the ExtrudeHone and gaskets. Hmmm....now you've got me thinking about that. How do they ensure that all of the casting sand is totally out of the fuel passages before assembly? Erick |
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Quote: Yeah, me too! Same exact behavior on my truck except I run about 70PSI and I've replaced LL #8 with an AD. Is the high-pressure oil pressure dropping due to the oil thinning at higher temps? GEM |
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All the (6-8) heads I've seen had drilled fuel passages, not cast. The fuel passages in the heads are plenty big enough--they could probably flow 5 gpm at 60 psi, which is 10x what the injectors need. Regarding the issues with hot vs cold engines, I'd suspect it to be caused by hot fuel releasing entrained air, rather than hot oil, but....Hot oil flows into the injector faster, and with greater energy, which could possibly lead to an effective "advance" in the timing when the injector fires. And, my understanding of the AE LL injector has been that it means Long Lead (Time)--it fires slower or later than a normal solenoid does. Doesn't SP Diesel make a device that lets you adjust the timing? Has anyone with cackle ever tried it? I've got several production AE injetors in the shop, and I'll remeasure the groove in the plungers tomorrow and post the actual measurements, but when I first checked them, I couldn't find more than .001" variation between the AD and AE's--just what I'd call normal production tolerances. I couldn't change where the groove is in the plunger, but it would be very easy to adjust where the groove is in relation to the bypass port in the barrel to either increase or decrease the amount of fuel in the pilot injection. |
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Quote: I agree, that's exactly what I have seen. Quote: Now that you brought it up, what pressure do you recommend running these trucks at? Just curious if fuel pressure will affect longevity of the injector, etc. |
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Iluvsteelies I agree that was a very concise overview summary Swamp Quote: And IMHO quite a job you have done .... my compliments .... some of your "pontificating" about injector operations in the 94-97 forums over the last year have been no less than .... WOW Quote: I also did not go to IU and don't even consider myself in your league of the "gearheads" here, but I'm totally shocked by that last sentence I attempted to understand this orientation issue over 18 months ago in THIS since I had a feeling then that if this bypass port could be randomly aligned inside the injector barrel (right term ), then this could be a major factor and one of the keys to understanding cackle/idle know was starting at the beginning with some sound engineering analysis, but the phases of the moon were not with me and the tides were against such a "unconvential approach" at the time. ... While I was taking measurements and doing observations others were more "actively" engaged in the "on-hands" reengineering of these complex fuel systems. Your observations now seem to confirm my concerns which back then were dismissed Thanks for the excellent observations, work and detailed description .... IMO you are only one of a very, very select few that truly understand our injectors and I very much respect you dedication and hard work in this area and look forward to what you can give us in the future.P.S. I apologize for the typing since your partner in crime Golfer and his danged "Skeeter killer" dyno run video is tangently responsible for me having to buy a new laptop which I have been struggling with to get up and running ... long story ... but coffee and the keyboard internals don't mix well HERE is that link that Jim was talking about and for more looooooong ago cackle discussions readers might enjoy looking at some of the links in THIS POST. Larry |
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Quote: Hmmmmmmm maybe I'm still confused ... getting easier and easier as the years mount up since I did my previous post before I read this one. My two previous concerns were if that "spill port" could have it's orientation changed in relation to both the fuel gallery supply and inside that injector "cup" that has the as I remember 4 larger holes that allow fuel into the injector fill cavity.Larry |
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Quote: Vacuum and diesel dont mix. It can cause liquid to become gas and then collapse violently. I bought an injection pump because of this little phenomenon. Larry. You would be suprise how durable a keyboard really is. I spilled a mocha on mine while I was using it. Believe it or not I ran it thru the dishwasher and put it back in service. |
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Will all the problems with the split shot injectors didn't Texas Town Car convert one of his trucks from split shot to single shot and reprogram the PCM? Is the too cost prohibitive? Sounds like a good solution if you all ready have a few bad injectors? Don't the single shots cost less too? What would 8 single shots and a PCM cost? Ken |
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You use the same cpm its just a code change that can be done with a chip. Than you just have get new injectors. If I was going to get new injectors I would look hard at single shots, new programing, and fuel mods and be done with it for good. DENNY |
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This is a reply to subman. I posted quite a while ago about the cackle appearing when the temp gauge hits the first mark on the OEM temp gauge. I installed SPA digital gauges a while back and noticed the truck does not cackle until the water temp hits at least 110 degrees F. Can someone remember or explain what parameters are changed by the PCM around 110-115 degrees F in relation to the HPOP or timing advance? I seem to remember the HPOP would reduce pressure via the PCM by about 10% when this temp is reached? My truck runs real strong on cold mornings until this temp range hits, then it will not run as strong and begins to cackle, miss, or make noise that was not there under that temp range. I'm not asking you to dispute if this is a cause or not, just wondering if anyone knows the programming of the PCM well enough to explain the parameters of the HPOP at this temp range. -Dave |
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I was basing the oil temp estimate off the analog coolant gage I have. I have not had a detectable power loss above 110° coolant temp, just the slight idle knock. I would be nice if the culprit was a program issue vice the LL#8 injector I still have. It was always curious to me that the engine ran so different(purred) while cold. I've been waffling quite awhile about changing out the LL based on reports here that no change was noticed after installing the AD injector. |
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Hmmmm After reading several of the latest posts, which I might add are very good, no flaming, just good theories and such, I am starting to look at it a different way. Since we have a good idea that it is air that is the major cause of the knock, is it possible that there is something in the system with relation to the way the injectors fire, on the left side, since it seems that the left side is where the #6 and #8 injectors are located (sitting in the drivers seat), I recall another poster saying the rail is capped on the rear of that side, and the front of the opposite side, so if it was a rail problem, it would manifest itself at the #1 & #3 injectors as well. If bleeding the fuel rail reduced the knock, then it would need to be determined why it only affects the one side and not the other, angle of the engine? I know in the late 70's, a few of the V8 engines suffered from oil problems in the #7 and #8 cylinders on those engines which were used in short trips, mainly due to the oil flowing back there and collecting over the valve stems, this was in both GM and Ford engines. Now with that in mind, if the engine is slightly tilted back, then the air in the right side would flow all the way to the end of the fuel rail and stay there, where the left side the air would try to move up towards the front, due to the natural tendancy for air to rise, and the fuel pressure pushing it back, so it remains where the #8 injector is located. It was just a random thought after reading the old post about bleeding the head after raising the rear end off the ground. Now about how the air gets in the system, why does a single shot injector work better than the split shot. If what was said before about the pulsing between shots, maybe it is brief, but if it happens enough times, wouldnt it create cavitation? I know a submarine can create cavitation even if it is 1000 feet below the surface under extreme pressures, so even thought the fuel is under pressure, there is still a chance cavitation can be created. Cavitation creates air, air creates knock, etc. If opening up the fuel system can aleviate the air that gets in there, and I am fairly certain it is being created internally, otherwise there would be leaks in the system somewhere that would show up eventually while sitting, since the air must be drawn in BEFORE the fuel pump and not after, then air that is being created by the cavitations, can be extracted before the injectors can deliver it. Just random thoughts, but this is how I tend to troubleshoot major network outages as well, since I am a network systems engineer, strange things happen and sometimes weird trains of thought solve them. Reason I am onto the air ingestion is because when I first got my truck, it was quiet, then one day I happened to pass someone and had it up to the redline in overdrive, then later that day I noticed it knocking, so somehow I got air in the system. Fuel tank was full, there are no leaks in the system, so the air had to come from somewhere internally, and I highly doubt it was from the fuel tank. It has since quieted down to the point where I have to really listen to hear it. Edited by ACD (12/29/03 04:22 PM) |
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I went to the ford dealer 2day to inquire about other things.. (rear main seal is bad, and pinion seal on diff is bad  ) I asked the tech about the knock noise, and he told me that the sound is normal. The electric fuel pumps have air lines to bleed out the air in the fuel, and they are supposed to be constantly sending 60psi of pressure to the motor, etc.. etc..I told him when I upgraded my injectors to stage II, i no longer experienced the idle knock cackle sound anymore. He remained quiet, and we continued to discuss my oil leak and stuff. Just though I would share what the dealer has informed me about the idle knock issue (its supposed to be normal). |
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The air is entrained in the fuel when you put it in your tank. My guess is that the injectors cause the air to release from the fuel and it remains in the fuel rail. Bob |
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koolkat812, You told your Dealer you replaced your injectors? If he accepted this and didn't start talking about voiding your powertrain warranty I think I would stick with that dealer for now even thought their service tech is an idiot! Traildust |
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Yeah, I told him about the injectors, turbo, shiftkit, chip, etc... And he didn't say anything about the warranty being void. And this is their Diesel Tech!!! He informed me their stance is, if all that is in there and it doesn't break anything then they will not void the warranty. If something where to break, and it was caused because of my toys installed then yes then warranty would be void. Example, I had an o-ring for the power steering system fail, and I lost steering and brakes. The truck was towed to the dealer and they looked at it, they also saw there was a chip in there. And informed me that if something else failed that was due to the chip my warranty would have been void. Thanks |
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ACD- Interesting ideas. It has also been noted that cyl's #6 & #8 are the only two to fire sequentially right next to each other, with 6 going first. That has been postulated as the reason 8 may only get a partial fuel fill. Swamp- Thanks for the insight about expressing the 1000-count injector test results as CC's. In your recent injector explanation, you mention the same thing that had been discussed earlier regarding the fuel "bypassed" during the split shot operation, namely that the fuel rail sees all that pressure. Given that liquids are incompressible, not only does the rail see that pressure wave, isn't it also necessary for some amount of fuel to physically flow out of the injector and in to the rail? How much fuel is bypassed in that instance? Perhaps ~20-30 mm's? Given that the rail is normally dead-ended, that means that fuel must must either displace fuel into another injector that happens to be only partially filled at that moment, or it must travel "backwards" thru the system... but there's those pesky check valves... Another interesting test would be to orient the bodies of a set of injectors so that all of the fuel bypass ports in the barrel are alingend with one of the 4 inlet ports in the body. Call this set "Likely Cacklers". Run them in a stock fuel setup and observe. Then pull the injectors, and rotate the body's 45 degrees so that the bypass port is firing into the body, effectively dampening the effect somewhat. Call these "Unlikely Cacklers", and run them to compare results. OK, Enough rambling. -Steve |
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Just got back from Christmas and found all this very interesting .... I too have found that different oils change the sound of the motor... I run Delo 400 because I found it to be the most helpfull in keeping away the idle knock after running awhile. Rotella seemed to make the truck real noisy after only about 500 miles... the same could be said for Delvac... I also was interested in the timing issues that others have brought up... I asked abou this before and no one responded, but after I changed out my CPS I noticed increased noise and what seemed like less power. My mileage also went down from 14-15 in town to 12-13... Since the CPS is responsible for the timing of the motor could it be that some of these CPS's have tighter tolerances than others and just operate better... Has anyone with a bad cackler tried changing the CPS with a non-cackler truck? Also in regards to the orientation of the injectors... Do I understand this right, the orientation is off and the fuel is not being sprayed into the heart of the cylinder? This would sort of be like indexing sparkplugs so the gap was facing the center of the cylinder to keep from shielding any of the spark. Also I thought Dave Lott and the Mini-Me injectors came in Split shot and single shot versions and he could reprogram the truck to run either.... Maybe he could comment on that and if so if he noticed a difference. |
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Cackle Revisted
