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Discussion Starter · #1 · (Edited)
This topic of "Injector Face Coking" and how to remove it was started on a thread about something else so it was suggested we start a new thread.
 

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Discussion Starter · #2 · (Edited)
Part 1 of 2:

Hi Bork, No not at all. Diesels love running up there. I stick or brick on the pedal therapy with additives in the fuel additives for hours, not a problem at all.its good to let diesels run for periods of time at different rpms.......
Speaking of which, babying and not letting them live at sustained high rpms and without the proper additive that can dissolve carbon, is the number one cause of injector nozzle coking which in turn effects the spray pattern interfering one with the diameter of the spray patter, then builds encroaching enough into pattern it then interferes with all fuel being atomized. As it bit or side further encroaches into the pattern and now 50percent so so hit the coking no longer atomized and you dilute your oil wearing things prematurely at the same time, you burn a hole in your piston and unless you are looking in the mirror and seeing smoke or have your EGT gauge probe in the manifold on the bank where this is happening. Before it manifests itself in that extreme form, it will show up as a slow loss of power over time but as little as 6HOURS of running in some tests. Slow decrease in fuel economy.
Some partially logically believe is 20k-30k psi should be enough blasting to keep that from happening. Partially correct to a degree but as the does hit it those two factors are happening; spray pattern narrowing and atomized fuel contact with it that becomes unatomized raw fuel before being burnt. You need an additive that dissolves that encroaching edge of the coking line back far enough to prevent the fuel to Coke contact.

Injector face coking is a subject that should get way more attention on the TDS.

We kinda fall into chasing down common I'm broken down problems and I feel overlook items like this that rob us slowly overtime so it's not a felt dramatic change until you are driving tank after tank going, hmmmm?

Lots of lab testing on this by manufacturers.
 

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Discussion Starter · #3 ·
Part 2 of 2:

We can start a whole new thread on subject and we can dig up different engine manufacturer's own testing on the condition. That will be cool. I'm not the guy for linking to here to post but some of you guys are experts on that.
Start with searching using search words and then the engine manufacturer. All have done long running test for high hours and you can see power dropping off. They pull injectors and you can see the build up on tip and with magnification you can see the build up have its leading edge encroaching on the offices. They run different types of fuel system additives and run for continuous hours and monitor power drop off from where they left off. Use the correct additive the spray will continue to contact that leading edge but it starts dissolving back that leading edge that was encroaching on office. Use a general cleaner it might just clean up the fuel system from tank to just prior to the injector tip. Get a biocide and you will just kill;algae, yeast , organic funk and do nothing else but that just kill the stuff which in turn clogs up your filter, so you then need a cleaner. Have injectors with that coking encroaching those things will do nothing. Get the right cleaner that contains a decarbonizer you can disobey back that leading edge.
Picture a plant mist sprayer. Your nozzle is going thru a hole in card board covering a paper towel tube size acrylic cylinder. You spay and can see a spray mist pattern going in. Now your acrylic cylinder has a slot in it tight below that cover plate with hole you inserted the plant mister nozzle into, to spray into cylinder. Now you have a thin card that fits perfectly in that slot in the cylinder. It has a hole in the center of it for your spray to pass thru into acrylic cylinder. It's hole is just slightly smaller than the hole up top you are spraying into. Now spray. You see the pattern start but hits the edge of that smaller hole in the card with slightly smaller office size and you will see mist hitting it and instantly turning to water on the outer circumference of the patter while core of pattern can be seen as passing thru in a mist state. Gotta get that edge melting back. I'm a firm believer of getting them professionally cleaned and tested. What you gain over time just in fuel, let alone missing out on power or in bad causes the real bad ugly damaging effects, pays for itself.
You end up properly maintaing your truck and getting the benefits. You as a pro move on while out being done. They come back in you know they are clean, tested and ready to send out with confidence you have gone the extra mile in assuring quality work and maintaing and growing a business relationship.
You can move this I won't be typing this much on the subject twice. Won't let me do smily face emoji.
 

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Politely ask to have my statements and the questions and my answers from other thread migrated here, if you wish.
1:45am. and just wrote a follow up in there. I'm out. You all have a great day tomorrow.
 

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Good morning, Love Liqui Moly Diesel Purge, Germans developed the diesel and they generally only market quality products. There is 0 risk of using it in your 7.3 and damaging something.
I do like Dieselkleen for regular use.

I'm really nervous about this thread turning main focus to additives right away with the ensuing posts using the word snake oil.

I like the idea of members interested in learning about the condition itself. I'm hoping members go outside of the comfort zone of the Dieselstop and erase researching this condition and dragging the back. Additives are an important part of maintainance for your truck and can effect the condition. For example expanding on what I have written. High RPMs,,, the. effects goes to what some people are referring to by such high pressure blasting material away. If you are always living in low rpms, the encroachment leading edge will get closer to the offices or pintle pin hole and protruding pin in that first gen type injectors in other engines. High RPMs increase pressure which will help keep that leading edge back before build up builds in mass and strength.

I did not start this thread but in hind site should just let it just take its natural course as sometimes other things like this sprout from the conversation.

Let it take its natural course, of course including snake oil posts before we can get true condition info dragged in here.

This is a great community and like seeing people wanting to dig in and learn. It helps us be better at maintaining and repairing trucks.
Glad to be a member here.
Nick
 

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Here's a few articles I found regarding the subject.

They're not complete documents (you need to create an account apparently to view the whole thing) but from reading the intro for each paper, it seems that the cause is often due to metals in the fuel (zinc for example) and the fact that the size of the holes in the injectors have continually become smaller over the years (with more holes). The smaller size holes allow for slightly better fuel atomization and better combustion (vehicle can pass emissions easier) but also increases the affect that these deposits can have on performance. 4 small holes are easier to foul than one large one.

https://dieselnet.com/tech/engine_fi_nozzle_deposits.php
Injection Nozzle Coking Mechanism in Common-rail Diesel Engine

There are no comments specifically on how to avoid this or how to clean/service injectors while they're in the engine though... I'll do more digging and see what I can come up with.
 

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ERT01 please keep us posted, I will be following this closely. I will try to find the diesel purge but so far no luck locally. I believe i have one or more that is not atomizing correctly and I use diesel kleen every tank.
 

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This is a very interesting article on the subject and has very good photos showing new tips compared to tips that have deposits on them as well as the spray pattern of a new tip vs the spray pattern of a fouled tip.

http://www.innospecinc.com/images/p...e-that-has-evolved-with-engine-technology.pdf

"Historically deposits have been generated from a number of sources: bio-contamination, both aerobic and non-aerobic, water contamination, lube oil adulteration, additives, dirt, metals in fuel, and biodiesel degradation. These may be ascribed to “poor housekeeping, incorrect additivation, deliberate adulteration or some combination.”
 

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That's the spirit fellas. Hard contaminates from the system caught in injector will not be removed chemically.


Pet wolf, not a challenge but what is leading you to believe that?


Keep in mind fellas we still have mechanical injector stiction issues to get to which in part can be from letting injectors live too long at a given RPMs. 7.3s usually suffer from stiction at lower rpms and come back on line with higher rpms and hydro pressure. 6.0 like to stick starting around 2500 rpms. Whole other thread to be started here.
Glad to see the enthusiasm.?
 

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In researching how to clean injectors while on the vehicle, I pretty much just got slammed with ads for every additive on the market... as I was sifting through them (to find more ACTUAL scientific analysis), I saw this method of walnut blasting that BMW recommends for their direct injection engine and thought it was interesting. I don't think it really applies to our diesels, but I thought it was kinda neat anyways:

Walnut Blasting BMW engines
 

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As I get more time I will follow up on these articles, thank you.

Nick I still get white smoke at idle. and low rpm miss while driving slow speeds. runs perfect at high speed/rpm and no miss at idle. if she idles very long i get a cloud of white smoke on take off that stops within seconds. I have posted on this issue before and keep researching but no one has same problem. your advice is greatly appreciated and respected
 

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Great thread and thanks for the articles.

Just a thought, and I haven not seen any data, but would water injection clean up the injector tips? I realize its like blanket cleaning, but I wonder if that would keep the combustion chamber clean?
 

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Discussion Starter · #15 · (Edited)
Here is an introductory level video that helps explain why Fuel Additives are beneficial for guys new to diesels:

http://youtu.be/6tTlbAzEHLQ
 

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Good video. Though I would really like to see an analysis of the common deposits on injectors and see exactly HOW the additives clean it off.

Today I installed my better and more permanent pre-pump filter (was running the dinky little clear Baldwin 7745 and now I'm running a Napa 4348) and when I put the filter in, I filled it up with LiquiMoly Diesel Purge.

No crazy noticeable difference after running the diesel purge through the engine, but I guess time will tell. I plan to make the diesel purge part of my regular fuel filter maintenance routine. Hopefully it'll keep my injectors happy and healthy.
 

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Discussion Starter · #17 ·
Good video. Though I would really like to see an analysis of the common deposits on injectors and see exactly HOW the additives clean it off.
Not sure I follow. How many different ways could they clean it off?

Basicaaly the detergent would attack the coke deposit at a molecular level and then high tempersture and pressure would do the rest.

That is the identical process that any detergent would use including Diesel Purge.

Right?
 

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The oil side of the injector wears out much faster than the fuel side.

Good oil and filtration for the oil is more important.

But running liquimoly every 6 months can't hurt either to keep the fuel side clean.

Biodiesel is the worst culprit. It can leave lots of deposits.
 

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Discussion Starter · #19 ·
The oil side of the injector wears out much faster than the fuel side.

Good oil and filtration for the oil is more important.

But running liquimoly every 6 months can't hurt either to keep the fuel side clean.

Biodiesel is the worst culprit. It can leave lots of deposits.
Blue, I have seen that certain types of Biodiesel are prone to leaving coke deposits during the combustion process. Its kind of counter/intuitive since Bio is reputed for its solvent or natural detergent qualities.

I have read that good quality Biodiesel does not result in Coke deposits...it depends on the Bio and the source. The industry has really made improvements over the years according to what I have read anyway.
 

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Ok guys, here ya go. I did best I could with Photo. The coking is clearly visible, ton of that crud. It I can see with magnification the office holes. You look through jagged eccentric holes coming thru the coking. This effects the outer layer circumference of the spray parent unatomizing that layer of fuel. At that point it become a self compounding problems.
About 130k BTW. Look at jagged build up at 12 o'clock on tip, in photo.
This is where you stop. These will be paint numbered on coil top injectors will be bubble wrapped and sent to Arundle Diesel. I instruct; first ohm, then check poppet clearance, then sonically clean, then install new orings and copper washer, install in test rig, fire it up and flow into graduated cylinders. Here the spray pattern is observed at different pressures. The fluid is captured in graduated cylinders. Volume is measured. All then compared to each other for balance. It's all about balance for silky silky, boys.
Nick
 

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