Problem with fuel injection harness from Painless - fuel pump stays on ???

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Jun 4, 2004
Denison, Texas
I need some help from those who have used a Fuel Injected harness from (Painless)
I completed the 5.3L Vortech swap - mated it up to my SM465 4-speed and all is good. Engine started and runs good, but as soon as I connect the positive battery terminal to the battery - the fuel pump starts pumping.
Repeat - not when I turn the key, but as soon as I connect the battery.
I called Painless and they think it's my computer, but it ran great the day I pulled it out of a 2002 Chevy truck. Upon turning the key to start-run, it should pressurize the system and then the PCM takes over the signal to start/stop the fuel pump, but in my case it just stays on.
Has anyone ever seen or heard of this ?
By the way - it's not wired straight to +12v, because if I pull the fuel pump relay or relay on fuse panel - it kills the pump like it should.
Thanks for any info...
If you think you can rule out ECM because it worked fine when last in use, then I guess I'd be asking Painless if there is any way they could have crossed/shorted 12V battery wire with fuel pump wire somewhere in the harness. I don't believe the 12V input and fuel pump output wires are neighbors in the plugs/pigtails, so I doubt they are merely disruptive neighbors???
it would be a simple mistake of popping the wire teminal in the wrong hole on the relay base to give you the problem you are describing. double check against the standard bosch relay numbering system you can find all over the internet.


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