Ford Powerstroke Diesel Forum banner

06 F250 Where to look for bad wires to injector #7

15K views 5 replies 4 participants last post by  Jleworth 
#1 ·
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.
 
See less See more
#2 ·
This will give you your wiring diagram:

www.powerstrokediesel.com/docs/EF_456.pdf

You can use the wiring diagram in the back of the book to trace from the injector to the FICM.

If you had a monitor, you could check to see if ICP and IPR were good, but with the truck running, my guess is it would be good. As for the fuel light, it doesn't mean it's empty but close. For the Lucas, it's not supposed to be harmful, I see a lot of stuff like "Exceeding the recommended dosage is not harmful to your vehicle (but why be wasteful)." For contaminated fuel in the excavator, that's out of my league. Our trucks are picky with what we put in it, you can't put used motor oil like in the old days that will hurt the injectors, but the excavator, I don't know about.

I would say this does need to get troubleshot soon. If you have a way of doing a contribution test, that could confirm Cylinder 7, and each cylinder can be shut off individually to see a sound change. If you wait too long and it is an injector, if it fails and the cylinder floods with diesel, then bad things can happen if hydrolcked.

These trucks are wicked expensive to throw parts at.
 
#3 · (Edited)
Thanks for the diagram!

I have one of those cheap Bluetooth OBDII dongles that connect to an app on a tablet, which is actually really nice to have considering it only costs about $4 on eBay, I also have an SCT X3 programmer and both will read DTCs and display PIDs. When you say monitor, do you mean just something that will display PIDs? Or are you talking about something like the Auto Engenuity?

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?

To be a little more clear on the situation that I was in when I was low on fuel, it got really low to the point that I heard some air run through, I didn't run it empty but damn close. As for contaminated fuel in the excavator, I have had it for a little while now and I've ran quite a few tanks of fuel through it, that I put in from a 5 gal can. I wouldn't think that the fuel would have been contaminated and even if it was I know that there are at least two filters that it would have to run through before it got to the injectors, but I also know that it can only take a tiny particle to clog and injector.

If it was a fuel related problem, could I still get the P0279 Cylinder #7 injector circuit low code?
 
#4 ·
Buzz test with the problem occurring. If the buzz on 7 is weak/ non existent, carefully plug in another injector to harness and run the test again. If buzz is solid with other injector, replace injector 7
 
#5 ·
I do not want ti distract from the suggestions above. ...only add to them.

You asked about the routing of cylinder 7 in the injector harness. Cycinder 7 is the passenger side rear injector. As such, the wires leading from the FICM to that injector have the longest travel of all of the injectors. The wires to injector #7 leave the FICM, move forward along the driver's side, cross over the valley, and then travel to the rear on the passenger side.

Here are some diagrams that may help:

6 0 Powerstroke Ficm Wiring Harness. 6. Wiring Diagrams Projects

If your issue is one of looking for chafing, this thread may help in general: http://www.powerstroke.org/forum/6-0-motor-problems/1096562-6-0-harness-chafing.html

You asked about whether a failed injector could be an injector issue. It's always possible, but the supplies in the FICM are banked - meaning a problem in the FICM power board is more likely to present itself on more than one injector, As you observed, a logic problem would be different.

A connector, wiring, or injector problem would definitely show more as a single injector failure.

Good luck.
 
#6 ·
Hey guys,

Thank you to everyone for your advice and suggestions. I've got my problem solved and my truck is back up and running again. Like I said in my last post, I sent the FICM out to FICM Fixer and he confirmed that the issue was the logic board. He told me that I had 2 transistors blow off the board, and that's what I could hear rattling around inside the enclosure. Since he had already rebuilt the power supply board he took the cost of that rebuild off the price he charges for a replacement FICM and I ended up paying him $201.00 and got working FICM in the mail two days later. The owner Shannon, spoke with me personally over the phone, as he did the last time that I sent my FICM out to him, and he was very helpful and willing to answer all the questions that I had about the work that he did on the FICM and also questions that I had about testing other components on the 6.0. I have no experience with the other repair shop that rebuilds FICM's, though I did hear that the will repair the logic boards, but I would highly recommend FICM Fixer to anyone that needs theirs repaired.
 
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