2007 F550 with the 6.0. I recently had some issues with low fuel pressure that was solved by the blue spring upgrade as discussed here: https://www.ford-trucks.com/forums/1...regulator.html After taking it for a ride it started to run a bit rough. From a stop it hardly had any take off power. Once it got moving it was ok. Had a buddy come over with his scanner. He pulled three codes. P0261, P0279 and P0275. They were for injector circuits low for 1,7 and 6 respectively. He then used the scanner to shut down each injector separately. There was a noticeable change in how the engine ran when we shut injector 6 down indicating it was functioning. There was no change in engine operation when we shut down injectors 1 and then 7 indicating they were not functioning. Prior to installing the blue spring kit I had installed new injectors; numbers 2 and 4. So I did unplug and remove the FICM during the injector installation. I did not touch the right bank of injectors nor any wiring on that side. These codes were not present prior to the installation of the new injectors and blue spring upgrade. Why would injector 6 appear to be functioning with the same circuit low code as the 2 injectors which do not appear to be functioning? Could it be as simple as one of the plugs is not connected properly to the FICM? There are three plugs connected to the FICM; does anyone know which plug leads to what? Any other thoughts?

 

Those three injectors are all on one plug of the FICM:

C1388A (X-1) Connector: Injector Control, Cyl. 1,4,6,7 (end plug)

Chances are you have a FICM issue or wiring/connector issue.

 

Do you know if that plug is the one closest to the firewall? I struggled getting that one in.

 

yes, it is

 

I'm not surprised. Thank you very much, Mark. I really appreciate it.

 

You probably already do/know all this, or even something better, so forgive me for going to this detail if it isn't needed.

When I remove the FICM, I plug the two vent openings on the degas bottle and remove it and push it over to the side. You don't have to necessarily plug the openings, you can "bungy it" to the side w/ the vent openings facing up, but I would always spill coolant without them being plugged. I also remove the air filter and intake tube (as one piece) and don't forget to disconnect the batteries.

I then put something thick over the hood latch and start to remove the FICM. After getting the hold-down nuts off, push in on each connector before pinching the connector locks, and then pull the connectors out. To re-install, I have the FICM tilted (higher on the front end and lower on the end near the firewall. The harness is flexible enough to twist so that you can carefully insert it (make sure it is parallel w/ the FICM itself). You can level it out to apply the force to hear the "click" of the connector locks. Repeat for the other two. Place the connected FICM over the studs and put the nuts on.

 

Thanks for the write up. Great info to post. That's pretty much what I did. Except for putting something over the hood latch. I just let that jab me in the stomach as punishment for buying a 6.0.

I removed the FICM and reinstalled it. Truck ran like a champ. Hope I'm done! Thanks again.

 

congrats. hope you have a good long run of reliability!