6.4L Misfiring

[Keith Browning]

This 2008 F450 with a 6.4L was actually towed in for a verified crank no start condition. I was able to eventually get it to fire with an alternate fuel supply (MAF cleaner). It runs rough and spews white unburnt fuel/smoke with the loudest fuel knock I have ever heard. MIL is on.

 

The codes are for fuel rail pressure too low, ICP low while cranking (fuel pressure) and fuel pump secondary circuit. I verified 5 PSI fuel pressure but I did not check FRP for some reason - but relative compression was perfect ruling out base engine concerns and I managed to get a power balance shot before closing up for the evening.

 

 

No misfire or injector codes probably because of the short running time. The engine shut down on the customer with no warning and would not re-fire. As I watched the power balance display it became evident that #6 is not playing by the rules. I suspect the injector is dumping fuel but what I am not sure of is what #5 and #8 are doing... are they misfiring as well or is this a normal reaction to a really bad miss to a cylinder adjacent in the firing order? I am used to seeing more compensation in the firing order on a 6.0L and as I look at what #1 #2 and #7 are doing I want to see the others react better than we see.

 

Has anyone had any experience with misfires on one of these? I am thinking the worst right now - possibly something coming apart in the HPFP or debris getting into the injectors. The fuel is good and nothing odd in my sample from the test port.

[Keith Browning]

This is a strange one.

 

 

Pinpoint testing revealed nothing - this is becoming the norm on these trucks in my opinion. So I decided to replace injector number six and re-evaluate this situation. Again I had trouble starting but when it finally fired it still missed exactly the same. I went back to my power balance screen and again began turning off injectors. After a couple minutes of running time the knock started skipping away and then vanished and the engine ran smooth. It was blowing heavy white smoke... so I did not want to run it in the shop any more than I already had and I hadn't put the coolant back in. I didn't put everything back on in case I needed to access the left valve cover again

 

/forums/images/%%GRAEMLIN_URL%%/scratchhead.gif Now I dint know if the cylinder was just so loaded with fuel or whether there is something else going on.

 

I then decided to wrap the engine up and fill the cooling system and take it outside to get it hot and blow out the exhaust. The amount of smoke was breathtaking! What you see in the picture is nothing compared to what it was. There was a light fluid dripping from the tailpipe that I thought was coolant but the coolant level was correct. Was it fuel? Maybe, but it sure didn't smell like it. The fluid disappeared and the smoke eventually cleared.

 

I have been running the truck for several hours with no more smoke or misfiring and I am closely watching the coolant level closely too. I am not convinced this truck is fixed.

 

/forums/images/%%GRAEMLIN_URL%%/whattodo.gif

[dean]

Hey Keith I just worked on 6.4 recently that had water in the fuel contamination. The customer knew about the condition but just drained the separator and continued to drive it. It only had 6000 miles on it. Vehicle was brought in with a lack of power complaint. It felt like it had a governor when driving it and would not exceed 2500 rpm in any gear (manual trans.) This thing idled perfectly. IT set the same codes youve listed and code for water in fuel. What I noticed is that short term fuel trim rates at an idle were all over the place. From -18 to +14. I also found on enhanced power balance that when I removed pcm fuel correction that the engine idled rough. I repaired the low pressure fuel system first for water contamination and then replaced all eight fuel injectors,high pressure pump, both rails and fuel cooler after flushing system. I know enough gas in fuel system and driven long enough can do the same damage. After repairs vehicle now has normal power and performance.

[mchan68]

You say you replaced cylinder #6 injector, but what about #2 and #7? That power balance screen shot to me, indicates cylinder #6 is not pulling its weight (or not enough fuel), and #5 and #8 are reacting due to being adjacent in the engine firing order. To me, it seems like #2 and #7 are giving you more (or too much) bang for the buck. What does relative compression look like?

 

Don't know if this is relevant, but I had an '03 6.0L in two weeks ago smoking white, running rough and losing coolant. The customer was all panicked thinking his head gaskets were blown. Did a power balance, and cylinder #4 looked virtually identical to what #2 and #7 looked like, in your screen shot. Relative compression revealed cylinder #5 down 8 to 10% in the yellow. Turned out the coolant loss was external due to leaking water pump. Replaced the water pump and cylinder #4 injector and all was well after that. Cylinder #5 also showed 0% (like all the other seven cylinders) on relative compression after the injector replacement on cylinder #4. My theory is that #5 indicating low, was due to being the adjacent cylinder in the firing order with the cylinder that had the issue.

[Keith Browning]

but relative compression was perfect ruling out base engine concerns

 

I replaced #6 because it was the worst on the display AND it was the only cylinder that made no change in engine sound when canceled. All I really wanted to see was cylinder #6 come to life and get the engine to start without the aid of an "alternate fuel source." That did not happen. If I had to guess that any one injector was causing the knock and low fuel rail pressure it was #6.

 

As for how the other injectors compensate I am not confident that this engine is exactly like a 6.0L is therefore I don't know if what you see is normal for a 6.4L. After another road test I am going to look at it again and see where my fuel trims are, then I am calling the fellas at the Hot-Line and run it by them.

 

Due to the lack of experience with this engine I simply don't know how certain failures will look or act like. In a way, we are once again at a disadvantage with a new product but instead of being over run with problems, this time we have very few problems resulting in less experience.

[Jim Warman]

What about engine oil level? Where is it sitting?

 

As far as replacing #6, I don't think there was really any other choice given the lack of any injector electrical codes and no indications of any cylinder sealing concerns. What might have told a story would be to try the "enhanced diagnostics" for injectors, after a fashion... Just give the thing a few minutes run time in enhanced mode to see if anything might "come back"... Let's not forget we are working with a whole new operating strategy.

 

A cylinder washed down with fuel and a sombrero full of fuel could certainly give some anxious moments after an injector replacement.... and could clear itself up after the repair (perhaps we may need to try clearing KAM after any fuel related events?).

 

What is interesting isn't so much that 2 and 7 (and to a lesser extent #1) are "so good".. but that everything else is so bad that it makes these few cylinders look "over-productive". Again, removing any chance of fuel trim manipulation might paint a different picture.

[Keith Browning]

What about engine oil level? Where is it sitting?

It was just above the indicator. There are two places on the engine that were marked "16.5 QTS" in black marker... which I cleaned off and then adjusted the level taking about two quarts out with my fluid evacuator. /forums/images/%%GRAEMLIN_URL%%/grin.gif Anyway, being somewhat fresh it was in decent condition and did not smell like fuel. I believe this event was recent and immediate and oil was not a player in this event.

 

 

Originally Posted By: Jim Warman

A cylinder washed down with fuel and a sombrero full of fuel could certainly give some anxious moments after an injector replacement.... and could clear itself up after the repair (perhaps we may need to try clearing KAM after any fuel related events?).

 

That is where my thoughts are headed with this. If that kind of fuel was going into the cylinder I should expect some damage... wouldn't I? Perhaps the diesel gods have spared this one for now.

[Aaron]

(perhaps we may need to try clearing KAM after any fuel related events?).

 

My memory, which is not working ALL that well with all the booze I've recently thrown at it, seems to serve me up something of Mr Dave Young mentioning something about resetting KAM after any fuel system repairs on these engines.

 

I may be wrong though.

[Mekanik]

Keith, I think these fuel systems are really sensitive to a loss of fuel pressure in the high pressure system. I'm thinking that #6 is overfuelling (or leaking into the cyl). I think that this will affect how the other injectors perform.

I had one that had the low icp codes and was not producing enough high pressure fuel for the PCM to fire the injectors. I took all the injectors out and then hooked them up to thier line, but pointing straight up. Then I cranked the engine to see which one was leaking fuel. I have to say that it wasn't much of a fuel leak. I was really suprised how low my FRP reading was.

This is still a learning experience for me every time I work on one of these things. /forums/images/%%GRAEMLIN_URL%%/coffee.gif

[eastendpowerstroke]

(perhaps we may need to try clearing KAM after any fuel related events?).

I had the same thoughts as well about this.

[Keith Browning]

Originally Posted By: Jim Warman

(perhaps we may need to try clearing KAM after any fuel related events?).

I had the same thoughts as well about this.

So did I and since I had the batteries disconnected during the injector repair the fuel trim tables were erased however the Hot-Line told me I HAD to go and do it manually. Well, I did a lot of reading... and I am not sure what the truth is but here it is in black and white.

 

Originally Posted By: 2008 6.4L PCED OBD2 Theory and Operation

The fuel system monitor is an on-board strategy designed to monitor and detect concerns within the fuel control system and its components. The fuel control system uses fuel trim tables stored in the powertrain control module (PCM) keep alive memory (KAM) to compensate for the variability that occurs in fuel system components due to normal wear and aging. The following functional checks and component monitors are executed during the fuel system monitor:

 

I am satisfied at this moment that the concern is corrected but I did follow up by contacting the Hot-Line. In addition to the fuel trim issue I was advised to replace the DOC and the DPF because of the fuel that ended up in the exhaust system causing the heavy smoke and dripping from the exhaust. I asked if this is documented anywhere to satisfy the Warranty Nazis should they bounce the claim but the Engineer was under the impression that it is but could not tell me where.

 

Will a little raw fuel really damage a DOC or DPF?

 

Answers to more questions:

• A stuck injector can bleed off enough fuel rail pressure to starve the other injectors and cause a no start condition.
• The engine knock was the indication that the suspect injector was leaking.
• If you replace a DPF always reset the DPF parameters.
• After ANY fuel system repair reset the short fuel trims.

But if you couldn't get the engine running you could remove the fuel rail plugs in the rear of the cylinder heads and turn on the fuel pump. Any fuel leaking detected indicates fuel leaking from a spill port. You can at least identify which cylinder bank that way.

 

OR

 

"I hear" and we have discussed this, mounting the injectors upside down on the fuel lines and turning the fuel pump on. Fuel leaking from any spill port or pintle should be obvious. I have yet to try this.

[Fordtechnician]

So now if I understand this right.... Disconnecting the batteries will clear the KAM AND reset the fuel trim? Hotline also wants me to reset the fuel trim.

I am asking because I am doing a short block for one that bent a rod from coolant injestion.

[BrunoWilimek]

Keith, I think these fuel systems are really sensitive to a loss of fuel pressure in the high pressure system. I'm thinking that #6 is overfuelling (or leaking into the cyl). I think that this will affect how the other injectors perform.

I had one that had the low icp codes and was not producing enough high pressure fuel for the PCM to fire the injectors. I took all the injectors out and then hooked them up to thier line, but pointing straight up. Then I cranked the engine to see which one was leaking fuel. I have to say that it wasn't much of a fuel leak. I was really suprised how low my FRP reading was.

This is still a learning experience for me every time I work on one of these things. /forums/images/%%GRAEMLIN_URL%%/coffee.gif

I had one that was a no start with low ICP(only around 1400 psi, if memory serves correctly). I called hotline and a sharp engineer mentioned the injector test you tried(upside down and hooked up with the old fuel lines-to test them only). He added that you could do one bank first(a 50-50 chance of getting the correct bank the first time). Before attempting this though, he had a less invasive way to narrow down the faulty injector. Remove all the glow plugs and have an assistant crank the engine while you watch for white fog at the glow plug hole. That will narrow it down to a cylinder(s). The reason for doing this is that the 6.4 injectors have a return passage that the fuel leaks to internally in the injector. Because of the extremely low pressure due to the internal leak, the pintle allows a small amount of fuel to leak past it, thus pinpointing the faulty injector. Keith could bypass this test because he was able to get a power balance reading to narrow it down to cylinder #6. After replacing the faulty injector, the truck has not been back for any further concerns. /forums/images/%%GRAEMLIN_URL%%/smile.gif

[Keith Browning]

After replacing the faulty injector, the truck has not been back for any further concerns.

/forums/images/%%GRAEMLIN_URL%%/whattodo.gif DONT JINX ME!!! /forums/images/%%GRAEMLIN_URL%%/whattodo.gif

 

I had to order a CAT and DPF which take two days to get so the truck is still here! /forums/images/%%GRAEMLIN_URL%%/laugh.gif

[BrunoWilimek]

Sorry, Keith, I was talking about the one I did, not yours. I hope yours is fixed as well after the other parts are replaced. /forums/images/%%GRAEMLIN_URL%%/thumbup.gif

[rlchv70]

Will a little raw fuel really damage a DOC or DPF?

Yes. A tiny bit of fuel wouldn't hurt. But larger amounts would lead to melting of the catalyst.

 

 

Originally Posted By: Keith Browning

"I hear" and we have discussed this, mounting the injectors upside down on the fuel lines and turning the fuel pump on. Fuel leaking from any spill port or pintle should be obvious. I have yet to try this.

 

I don't think this would work. You wouldn't be able to build enough pressure.

[DwayneGorniak]

Originally Posted By: Keith Browning

Will a little raw fuel really damage a DOC or DPF?

Yes. A tiny bit of fuel wouldn't hurt. But larger amounts would lead to melting of the catalyst.

 

 

Originally Posted By: Keith Browning

"I hear" and we have discussed this, mounting the injectors upside down on the fuel lines and turning the fuel pump on. Fuel leaking from any spill port or pintle should be obvious. I have yet to try this.

I don't think this would work. You wouldn't be able to build enough pressure.

I have done this and it didn't work. I also consider this dangerous. What brainstorm engineer came with the idea of pointing a nozzle that can spray anywhere from 5,000psi to 25,000psi straight up at your head or face or very close to it?

[Aaron]

What brainstorm engineer came with the idea of pointing a nozzle that can spray anywhere from 5,000psi to 25,000psi straight up at your head or face or very close to it?

My thoughts exactly when i saw this.

[Mekanik]

Originally Posted By: rlchv70

Originally Posted By: Keith Browning

Will a little raw fuel really damage a DOC or DPF?

Yes. A tiny bit of fuel wouldn't hurt. But larger amounts would lead to melting of the catalyst.

 

 

Originally Posted By: Keith Browning

"I hear" and we have discussed this, mounting the injectors upside down on the fuel lines and turning the fuel pump on. Fuel leaking from any spill port or pintle should be obvious. I have yet to try this.

I don't think this would work. You wouldn't be able to build enough pressure.

I have done this and it didn't work. I also consider this dangerous. What brainstorm engineer came with the idea of pointing a nozzle that can spray anywhere from 5,000psi to 25,000psi straight up at your head or face or very close to it?

The injectors are not plugged in. I didn't mention this but I thought it was obvious. Besides, the system would not build enough pressure to fire the injectors.

[Mekanik]

Originally Posted By: Keith Browning

 

"I hear" and we have discussed this' date=' mounting the injectors upside down on the fuel lines and turning the fuel pump on. Fuel leaking from any spill port or pintle should be obvious. I have yet to try this.

I don't think this would work. You wouldn't be able to build enough pressure. [/quote']

 

 

The fuel pump isn't going to build the neccesary pressure. That is why the engine needs to be cranking over.

[Keith Browning]

I assumed that the idea was to identify an injector that was physically broken or seized and allowing fuel to literally pass through uncontrolled, either through the pintle or the spill port. This also requires the assumption to be correct that the 4-6 psi created by the supply pump can, and will, reach the injectors with the KOEO.

 

I do not know if this is technically or truly possible. I was told first hand by a Navistar Field Manager that we could detect a leaking injector by removing the fuel plugs on the back of the heads to drain them, then run the fuel pump (supply?) and look for fuel leakage. If I am wrong please forgive my memory as I *think* that is what was stated and I don't want to mis-quote the man. Since high pressure would obviously be more effective, is there a way to disable the injectors and crank the engine to allow the HPFP generate high pressure? Would removing the valve covers and simply disconnecting the injectors work?

 

Does anyone remember using UV dye on the early 6.0L's when we had injectors leaking?

 

...just thinking out loud. /forums/images/%%GRAEMLIN_URL%%/hammer2.gif

[Jim Warman]

I, too, thought things might become obvious....

 

Years ago, we would see the odd Darwin Award hopeful peering down the throat(s) of a carburettor with the motor running.... This Einstein would then stroke the throttle with great gusto... And all I could figure is that he had some subconcious wish to see what he looks like without eyebrows...

 

We are "technician"... we should have at least some understanding of these things we work on.... "DUH" isn't a word we need to become familiar with.... thjough to avoid that familiarity, we do need to use the word THIMK.... err, THINQUE.... errrrrmmmm, TINK..... ahhh, piss on it.... I don't need to think.... I have a tool box and a pair of coveralls with my name on one tit.... I must already know everything there is to know....

 

Like I still tell my grown up son.... Just before you do something.... ask yourself "Why am I doing this?". Hopefully, there will be some reason in the reply....

[rlchv70]

Checking the return lines at the heads may help you isolate a bank, but it is really subjective.

 

An easy way to disable fuel injection is to disconnect the fuel rail sensor. This will set a code, but the injectors wouldn't fire.

 

The best way would be to crank the engine over a few times and then bore scope the cylinders through the glow plug holes to look for any fuel in the cylinders. You might be able to just remove the glow plugs and watch for fuel squirting out. Alternatively, you could remove the exhaust manifolds and watch for fuel coming out of the ports, but this is a PIA.

[Tony302600]

LoL, yea i was about to say....the injectors arent plugged in and the purpose is to find a leaking injector that just drips out. I couldnt imagine 15,000psi shooting around LoL. /forums/images/%%GRAEMLIN_URL%%/cover.gif

[Mekanik]

Checking the return lines at the heads may help you isolate a bank, but it is really subjective.

 

An easy way to disable fuel injection is to disconnect the fuel rail sensor. This will set a code, but the injectors wouldn't fire.

 

The best way would be to crank the engine over a few times and then bore scope the cylinders through the glow plug holes to look for any fuel in the cylinders. You might be able to just remove the glow plugs and watch for fuel squirting out. Alternatively, you could remove the exhaust manifolds and watch for fuel coming out of the ports, but this is a PIA.

Yeah right. I'm sure these manifolds come off really easily. /forums/images/%%GRAEMLIN_URL%%/banghead.gif The fuel was leaking out the spill port, not the pintle. I thought about removing the plugs on the cyl heads to look for fuel coming out the return rail, but I don't think it would be that obvious. There really isn't much ruel coming out the spill port. Besides, the injectors really aren't that big of a deal to remove. /forums/images/%%GRAEMLIN_URL%%/2cents.gif