got truck in my shop would run for a hour or so sputter and die. Start back up but do the same thing and die. I wiggle tested the ficm harness and it made the engine stumble so i replaced harness. engine still would run a hour or so and then die. now it won't start at all. ficm has 11.5 volts logic and constant power is the same out put with key on is 48 volts. i don't hear the injectors buzz when key is on could this still be a ficm issue or injectors.when i scanned it all eight injectors were throwing a code for high circuit? what am i missing.
Have you tried a known good FICM? I find it funny you would have codes on all 8 cylinders. I would check the harnesses for chaffing issues, every place it crosses anything that could rub through the harness cover/wire insulation. Did you have the codes before you changed the FICM harness? Did you get the harness connections plugged in good too the FICM? Are any of the pins bent where the FICM connectors go in? Are all the fuses still good in the fuse box in the engine compartment?
I didn't have a scanner before i replaced the ficm harness. when it was running for a hour after with the new ficm harness it had a kam sensor code, crankshaft position sensor and camshaft position sensor.
-there are no bent pins on ficm all connections are good.
- there is 11.5 volts power going into ficm and 48 volts out with key on.
- but why won't injectors buzz?
-when cranking the engine shows ficm sync yes as well so that should be a good thing.
- the fuel pressure from lift pump is 45-50psi .
- is there some way the ficm lost its programming? or pcm?
So now I tried unplugging the four passenger side injectors and the all the injectors still come up in the codes. I didn't think it was possible for it to be the ficm seeing that it has 12volts key power and 12 volts constant and 48 output. But correct me if I am wrong if the ficm was ok then the injectors should buzz when you cycle the key. Should I try putting the old harness back in just to see if it will run again or go after a ficm replacement? also can i buy a ficm from ford that is preprogrammed.
Plug the injectors back in, then i would unplug the injector harness connectors at the FICM and see if the same codes return. It sure would be nice if you had a known good FICM to test with. But from what M-Chan had to say it is entirely possible that the FICM is the problem.
i have four passenger side injectors un- plugged in right now and still all 8 injector codes are showing high circuit output. I will see in the morning if i can disconnect both fuel injection harnessess and if i still get the same codes i am assuming the ficm is shot.