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Hey I'm in the middle of my 5.3 swap. It's a 2000 5.3 and am using the 5.3 computer but a 96 5.7 fuse panel. Anyways my problem is that pin 9 c2 red (fuel pump relay control) is not providing a ground?!? So the fuel pun will not run. If I ground the wire the fuel pump will run. I can't figure out why the PCM will not ground the wire. I have checked my grounds and still nothing. Any help would be much appreciated! Thanks
The PCM provides power to the fuel pump relay, not a ground. Your original relay can be used but the actuating power must come from the new PCM, not the old one. Should be as simple as undoing the present power wire to the relay and using the Dark green/white wire from the new PCM to power up the relay.
Once the new wire is used to power the relay, it will, in essence, be grounded through the relay actuating coil.
BTW, welcome to the site. Keep us up to date with your swap. Pics would be cool too as we all like them around here.
Quote:
Originally Posted by Mickeymotormount
For the fuel pump relay there is a 12v constant power, 12v key power, a grey wire to give power to the fuel pump and then the green/white wire grounds the relay and turns the pump on. When I give it ground it works fine. When the PCM turns on it is supposed to give the relay a ground for 2 seconds as a primer and then when it is running. I will check for that wire for power, maybe I am wrong
Figured it out! Turns out you were right it's not a ground as I was told by some ppl😡 oh well that alot for the help! I o have 12v key on, grey wire for power to pump a ground and the green signal wire!
Glad to hear it!
maybe they were talking about the pcm supplying a ground to the STARTER RELAY?? i know thats how the newer starting systems work.
but glad to hear you got it going. always a good feeling to finally figure out the problem!