misfire on 2006 F550 6.0L with m/t (long)

p2k5 · May 14, 2006

I'm working on a 2006 F550 6.0L that has a bad misfire and buck in 1st and second gear and it goes away in 3rd and 4th gear. It has cont. dtc P2614 stored in memory without the mil on when the symptom is present. I checked fuel pressure under load and it's 48 psi, performed a power balance test when its missing and cannot isolate it to an individual cylinder. All the other pids appear to be normal. I think its setting the cam sensor dtc due to the misfire. I am going to remove the standpipes and inspect them for damage. Are the check valves are part of the d-ring assy on top of the standpipes? Have any of you ran into this concern before? By the way, this is my first time posting on this board. Any suggestions? I will keep you guys posted. Thank You.

Paul

gasgasman · May 14, 2006

Fuel pressure is too low. It should be 55psi or more.

I think you should correct the fuel pressure concern first.

Jim Warman · May 14, 2006

gasgasman, I heven't seen many that can sustain fuel pressure that high..... Changing pumps and quills never seems to solve any of the borderline ones.

Paul... I recall a troublesome no start with a repeating P2614.... IIRC, this code includes FICM and related wiring concerns (I think mine was a 04ish truck). The PC/ED wasn't as much help as it could have been and I resorted to the Gold coloured "bible" for guidance.

I felt that the concern was likely a chaffe concern... Our then shop foreman took over the duties but couldn't find any concerns with the harness.... tried a new FICM and the truck started... Put the old FICM back in and the truck started..... The concern hasn't resurfaced....

Gawd, I love this job...

Keith Browning · May 14, 2006

The fact that this is the first time I have seen the fuel spec of 45-55 PSI is a good omen. I haven't seen many 2006 trucks with a problem... or at least one's I needed to crack open a book for. /forums/images/%%GRAEMLIN_URL%%/smile.gif

Yes, the D-rings have the check valve in them on an 06.

Suggestions? Start hunting but be methodical. I recommend TSB 06-9-7 for starters. While you already have the valve covers off checking the D-rings you may as well remove the oil supply tubes to check the injectors: check the hold down clamp bolt torque indicating a damaged copper seal. Read this. If they leak it will affect fuel pressure in that bank. The engine in the article missed intermittently and ran better at higher RPM's. Closely inspect the injector inlet oil seals as well. I think you are looking at an erratic fuel or oil pressure issue. This includes wiring and sensors that control ICP and the IPR.

fleetingmoment · May 17, 2006

Could be sucking air from the primary filter on the frame. Air in the fuel would cause this and quickly trash injectors with out that cushy (air less) fuel.

HGM · May 17, 2006

45PSI is bare minimum under a load, that should be fine, though the air is a possibility too.. Is it RPM related,rather than gear?Have you tried monitoring and unplugging ICP while driving? Does it clear up? If so, its not a check valve.. The code makes me wonder if you have any other issues that come along with it.. Could it be the trigger wheel? Try monitoring FICM sync and Sync in graph form on the WDS to see if either drop out..Just a couple of thoughts.. You may want to try the baloon test too..

p2k5 · May 24, 2006

Update: Sorry for the delay, I had other 6.0L's to work on. The issue was wire chaffing from the main engine harness, when I pushed on the harness, under the turbo compressor inlet duct on the driver's side near number two cylinder, I can get the truck to stall at idle. It finally set more dtc's: the cam and crank dtc's: P2614, P2617, p0340, p0341- cam sensor performance dtc's, p0471, ep sensor range and peformance. And one time the truck did not want to start at all, due to the vref shorted to ground in the engine harness, the ebp sensor ckt. I ordered an engine harness for the truck. For now, I temporary routed the harness away from the intake manfold and turbo inlet clamp and road tested the vehicle, the truck runs good. I couldn't see the chaffe, but I will cut the loom open to see what wire is damaged and will report back. Thank you all for your help.

Paul

Jim Warman · May 24, 2006

I forget which tech I was talking to on Hotline the other day on a very, very intermittent. I was told that he has heard of the shielding wire in the harness working through the insulation of the wires in the harness...

Haven't seen one myself, but this could account for some of the oddball concerns we see.