Hey guys,
My 06 F250 (6.0) has started acting up on me in the last few days and I hoped that I could get some advice on where to start looking for the problem. I was moving some trailers the other day and she was running just fine but as I got off the interstate and stopped, I noticed something wasn't right. The engine started running rough and it sounded like it was missing but it didn't throw a code and a minute or so later it smoothed out again. The next day I started it and let it warm up and it sounded fine but as soon as I started driving it sounded like it was missing again and it didn't want to shift. After a few minutes, as I was trying to accelerate, it smoothed out again but as soon as I stopped it would start running rough again. After shutting it off and starting back up again, I got an engine light, P0279- (Cylinder #7 injector circuit low). I cleared it to see if it would come back up again but it didn't and for the rest of the day it ran fine. The next day, she was back to running rough again and the light was back on, so I know I definitely have an issue. In addition to the P0279 code I also now have P0281- (Cylinder #7 contribution/balance) which I believe is probably due to the previous code. I have been reading up on the problem and it seems that the issue is likely electrical. I sent my FICM in a few years back to FICM Fixer and he went through it for me, he offers a lifetime warranty on the FICM voltage and I'm guessing that's not because he enjoys fixing them over and over, so I don't really think that I have an issue there but I could be wrong. I was going to start my search by looking for chaffed wires but I was wondering if anyone could give me any clues on the best places to look for wiring issues with injector #7. If so, I would much appreciate it. I have been fairly convinced that I have an electrical/wiring problem from the way the problem would start and stop as the vehicle bounced around, but I suppose that could also be a fuel related issue. I had forgotten up until now that before I filled the tank up and these problems started, I went out to the property that I just bought and I forgot to check my fuel beforehand and the fuel light came on just as I pulled in the driveway. It was late at night and the only gas station within range was closed so rather than staying the night in my truck and waiting for the gas station to open, I drained some fuel out of the excavator that I just bought. When I filled the excavator I put some of that Lucas Fuel Stabilizer in it, which I don't normally use but I found a gallon that I had from awhile back and figured "what the hell". I am thinking now that the problem could also be a result of contaminated fuel from the excavator, running the tank almost empty, or maybe the fuel treatment actually broke some stuff free and clogged the injector. Let me know what you guys think. I would like to think that if my fuel mishap was the cause, I would probably be having problems on other injectors as well.

 

Update-

I should have and wish I did check the PIDs before I tore into it today but I was pretty certain that I was going to find a chafed wire in the injector harness. I pulled it out and looked it over but found nothing. I have read a few posts about checking the resistance between the coils on the injectors so I did that on injector #7 and #5 just for reference, and got 0.5 Ohm between both pins 1 & 2 and pins 3 & 4, which is within what I believe that it should be. I'm guessing that's probably not surefire test for the injectors but I think that more than likely they're just fine. I had the FICM on the bench and I went to wipe the dust off of it and when I picked it up I could hear something small rattling around inside. Before I sent the FICM out to get repaired a few years back I had it opened up and I remember seeing some type of hard resin-like insulation around some of the capacitors, if I recall correctly. I suppose that it could be just a chunk of the insulation but FICM Fixer has a warranty on their repairs and they put tamper evident paint on the screws so I am waiting to talk to them before I open it up and check it out. I would like to think that I found the problem but I'm still a little confused because I would think that a bad FICM would cause problems with more than one injector and it doesn't seem like it would have been as intermittent as it was. I am also concerned because I believe that FICM Fixer and other repair shops only rebuild/replace the power board on the FICM and I would assume that if the FICM is what is causing the problem, it is likely due to the logic board having failed. Any thoughts?

 

First, post this over in the Diesel 6.0 section, lots of good help over th here.
Second, I would start by checking the connections under the FICM. Are any of the clips broken? Any corsion in the connectors?