Fuel pump circuit failure, need help

[ELuckie]

I have a 1994 SHO and for quite some time it has had trouble starting. I will turn the key two or three times and it would not start and then it would. This has gone on for a year and now it will not start at all. The fuel pump is not priming when the ignition switch is in 'run' position. The KOEO code is 556, Primiay Circuit failure. The ICM module is clicking, the fuses are good. The pink/black wire running to the inertia switch is getting about 8 v. when ignition is in 'run' position. Inertia switch checks out ok. At the final connection to the fuel pump the pink/black wire is only getting 6v. According to my wiring chart this wire does not run anywhere else than from the inertia switch to the fuel pump. Is there somewhere else this wire runs? I disconnected each end and it appears to have conductivity with the ground. Has anyone had this kind of problem and can anyone offer me some advice on what to do? I replaced the fuel pump last year thinking that was the problem, but obviously it was not.
Also, there is a pink/red wire that is not on my diagram, does anyone know where it goes?
I got some instructions for testing the ICM to test for voltage or grounding at certain terminals. I need to know how to run a lead on them if it is plugged into the module. Can the module be repaired and how??
Thanks, Eric

 

[Marccus]

You are further into diagnosing the problem with the fuel pump circuit than when I had to deal with it. My wiring diagrams were in storage and I couldn't trace the circuit as well.

I first replaced the fuel pump but that did no good. Then, I did trace things far enough that I figured the pump relay circuit in the IRCM (located under the fan shroud on the driver's side) and replaced it. The car starts and runs fine with no hesitation at any time (which it had before when moving out of 1st gear from a full stop). Perhaps my original fuel pump was OK still at 285,000 miles, but it was probabley due anyway. I haven't taken the time to take apart the IRCM to see if something had to be or could be repaired inside.

Hopes this helps. Hand in there and "eventually" you'll solve the problem.



'89 SHO (essentially stock) with 288,000 miles and STILL on the original alternator and 2nd water pump with 190,000 miles.