ablokzyl Posted March 6, 2012 Share Posted March 6, 2012 Ive got an 03 F250 6.0L with 170,000 miles in my shop at home. It has a Banks Six Gun with IQ, a spiral flow intake system and a Bulletproof Diesel EGR cooler delete. The truck will start bucking hard like it has a bad miss at full power. I checked codes. The only code is a P0341 cam sensor code. He had already installed a new cam sensor. I started a visual inspection and found that the turbo had been dusted very bad. I did a reletive compression and found 0% on all eight cylinders. I told him that he needed a turbo before I went any further. He bought an upgraded Garret towing turbo. I installed it and as you can guess the problem is still there. FICM voltage never drops below 47.5 volts at any time. I checked powerbalance while it was cold and found 3 injectors missing hard. Told him about it and he wanted all eight so I installed them. The truck starts smooth as glass now but the original problem is still there. I have been checking for a rubbed through harness but nothting shows up. On of the guys at the shop had me try a known good MAF. Not the problem. Fuel Pressure is 48 psi with a mechanical guage. Im running out of ideas......any thoughts? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted March 6, 2012 Share Posted March 6, 2012 I am leaning towards a rusted cam sensor pad. It can be proved out with a visual and or a lab scope. You guys get rusty stuff down in PA? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted March 6, 2012 Share Posted March 6, 2012 Thinking out loud here: Are you using an IDS for diag? Does the RPM signal graph stay level while the bucking is occurring? Do any other graphs show the buck, like EBP, ICP, IPR, VGT, or anything? FP is 48PSI at WOT under load, right? If the turbo is dusted, quite possibly the engine is too, even though it shows 0% relative it still could be low on compression. It might not be your problem but a mechanical check sounds like a good idea. CMP rust jacking is quite common, and although it generally isn't this complaint you might want to pull it and clean the block flange. Can you be more specific about the complaint? "Bucking" and "bad miss" are two completely different things to me. Does it feel like a cylinder has dropped out, dead miss, skip or whatever your favorite term is? Or, does it buck hard like all 8 are shutting off for a split second? Let us know.... Quote Link to comment Share on other sites More sharing options...
ablokzyl Posted March 6, 2012 Author Share Posted March 6, 2012 Bruce I am using IDS for diag. I will check the graphs tomorrow after I get out of work. Yes 48 psi at the secondary housing under WOT while driving down the road. I will also do a manual compression check but it does run smooth as glass if Im easy on it. I diud check the cmp flange and it was pretty clean. Bucking and a hard miss are pretty close in my book, but I would call it a dead miss. Oh and while the problem is happening the powerbalance screen locks up everytime it misses Quote Link to comment Share on other sites More sharing options...
Steve Mutter Posted March 6, 2012 Share Posted March 6, 2012 So It has some kind of aftermarket intake elbow? Do they still have the egr throttle plate on the truck? If it does try unplugging the egr throttle sensor and running the truck maybe that thing is acting up. Quote Link to comment Share on other sites More sharing options...
ablokzyl Posted March 6, 2012 Author Share Posted March 6, 2012 Yeah it has an aftermarket intake elbow with a K&N airfilter hanging off the end of it....Yes it does still have the egr throttle plate.....I will try it tomorrow Quote Link to comment Share on other sites More sharing options...
mchan68 Posted March 6, 2012 Share Posted March 6, 2012 If power balance is locking up when the symptom occurs, that almost tells me you have a harness issue. The owner has already spent money on eight new injectors and a turbo. What's an engine harness now? Quote Link to comment Share on other sites More sharing options...
joshbuys Posted March 6, 2012 Share Posted March 6, 2012 run 2 jumper wires as a temporary overlay on the cam sensor circuit to see if it corrects the condition. I haven't had one act exactly as you describe, but I've quickly diagnosed many bad harnesses with damaged cmp wiring using this method. Quote Link to comment Share on other sites More sharing options...
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