[j cAT]

Originally Posted by rk396

I have a 97 k1500, 4wd, 350 (5.7). For the past year or so i've been having problems with the fuel pump. Mainly that the connection inside the tank has been corroding and causing the pump to "fail". I seem to have that worked out finally, and now drive the truck about once a week.

last week it failed to start. So i suspected the pump was at fault again. After confirming that the pump was functioning correctly. i turned my attentiion up streem. I've checked the relay, and it was working fine. I found that i wasn't getting a prime pump signal OR a signal to the coil side of the relay (while cranking). I then checked for spark... nothing. Then i hooked a scanner (a simple code reader) to the DLC, and it failed to link. THe scanner does work, and the dlc plug shows good ground/continuity and voltage where necessary. All the obvious fuses are ok, and the cig lighter works.

I started checking voltages and grounds at the PCM, and i found several things.

1) C3-#9 doesn't show voltage. This is a white wire coming from the ICM. I suspect that this won't show anything until the engine is cranking however. any one know for sure?

2) C3-17, and 18 show good ground( continuity and low resistance) when the key is off. When the Key is on It doesn't. It shows continuity but with a Really High Resistance. When i do this test with C1 and C2 unplugged i loose the 18 ground all together, and the 17 ground is good.

Am i barking up the wrong tree here thinking it could be a grounding issue? i'm kinda at a loss as for what's going on. The fact i can't link up says that the pcm may be bad. I do appear to be getting power to all the correct pin outs as well.

any one have any thoguhts, or where to look next? any help would be MOST appreciated. thanks

as you crank engine crank sensors tell computor that engine is rotating and it is ok to initiate spark etc. so this is suspect.as well as grounds electrical conn . rodent damage etc........