Ford Power Stroke Nation banner

need help diagnosing 6.0 raw fuel out tailpipe

15K views 16 replies 6 participants last post by  sidssm 
#1 ·
Hello all. I have an 05 f250 6.0 auto that has me about to pull my hair out. Any help/input is really appreciated.
Truck starts quick, idles smooth, and sounds good. The problem arises when the accelerator pedal is pressed. When cold it will rev up to 1200 rpms good and then starts missing and will die if the pedal isnt released. After it runs for about 15 mins it will rev all the way but it misses and struggles from 1200-2100 rpms. Runs good and smooth up to 1200 and smooth after 2100. I have searched and read until i am blue in the face.
To this point I have replaced all eight injectors, camshaft position sensor, ficm, egr valve, pcm, accelerator pedal, cooling fan. I am getting a glow plug #6 circiut failure code and that is it. I am going to replace # 6 glow plug next. I dont think that could cause this problem but will address it too. Today i noticed that if yougive it fuel one time real quick when it starts it revs fine but that first rev was all i got until it warmed up. Oh yeah and when it is in the missing rpm range this white smoke that smells like raw fuel. To get the point across it looks like a cloudmaker until it warms up. No coolant loss and no pressure in the degas. Any input is appreciated. Thanks SEth
 
#3 ·
I would do a compresion check or borescope all the glow plug holes. Make sure you dont have any burnt valves or ones sticking open. If you are dumping fuel in but lacking compression it will not burn but will get pushed out during the exhaust stroke. It should be pretty easy to tell if this is the case as the glow plug will probably be soaked. Cylinder #6 might be a good place to start.
 
#5 ·
Thanks for replies.
fuel pressure is about 55 and doesnt change (also has new fuel filter)
No programer ( I have installed another pcm and ficm)
I dont have a miss at an idle and it doesnt miss above 2100 rpms and if you give it fuel as soon as it starts it will rev up with out a miss one time. I think that would rule out a bent valve or any other problem relating to mechanical problem.
 
#7 ·
Personally I wouldn't assume there is no mechanical problem. Maybe there is not but it sounds like you are just throwing parts at it which doesn't really seem like a better option than looking into something that might be wrong because you don't think it is a problem. I didnt say a bent valve but it could possible be a valve not seating or a flat spot on the cam.

Good luck on your parts swapping. Hope it goes well.
 
#15 ·
I am not a parts swapper like you suggest, although I have started doing that on the 6.0. In the past year I have worked on several 6.0's that have had electrical problems (bad sensors and injectors) that did not show any codes. I am to the point now that a scanner, half of the time, is only useful for checking icp, ipr dc. I dont understand how so many different trucks can have a bad sensor and not store trouble codes. There were several indications that the engine is sound mechanically, like the first smooth non smoking rev within 2 seconds of starting it and the absence of a miss at idle and above 2100 rpms. The glow plug looked normal when I changed it but it was non functional. Replacing it did let the code clear. I now have a storage container with 8 good injectors, crank sensor, icp sensor, Ipr, cam sensor, extra engine harness, and a ficm. I will be adding to that container an ebp sensor, accelerator pedal, and a mass air flow sensor. I have fixed two 6.0's this summer that had bad cam sensors that did not set dtc. Both would not start, one wouldnt start at all and the other would not start intermittently. One customer could start his with starting fluid and it would run until he shut it down, no codes but put a cam sensor in and fixed it.
 
#9 ·
About how many miles?? EGR still intact? They can do that ,they will open too soon losing the charge from the turbo. Have you checked the turbo and were they new reman fuel injectors from ford or some cheap ebay junk?
 
#17 ·
Well been a long day. I replaced the bad glow plug, replaced the crank sensor with no luck. A friend suggest that I replace the exhaust back pressure sensor. Reluctently I did but I was at the end of my rope. Unbelievably it does not smoke, and the missing/struggling is completely gone. Thanks Hank for the suggestion:bowfast:. I really appreciate the input from everyone.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top