I searched, but didn't really find an answer so here goes...

I recently rebuilt my LT1 and after 3 years of sitting, I decided to replace the fuel pump. I siphoned out the old gas (maybe 2 gals) and dropped the tank, installed the 255lph, hooked it back up. Replaced fuel with 5 gals of 93 octane, and turned the key...no noise, no fuel pressure.

That's where my questions begin.

1) I checked the voltage at the back and only 4 volts were getting there. I replaced the relay, and PCM fuse. (12 volts at the relay and fuse)

2) I replaced the filter
3) I could not find the lost ground, or what ever is losing power, I ran two wires to the back. plugged them into the harness with 12 volts...no noise, and the pump isn't running.
4) I decided then to check my old pump, my spare LS1 pump, and my walbro pump...nothing...I had them in a jar of gas just to make sure I didn't run them dry.

If I run 12 volts to a pump...shouldn't it turn on? or am I missing something?

Please help


Thanks

Derek

 

You should be able to run the pump by supplying +12V to the gray "prime" connector by the PCM.

Sounds like you may have a wiring problem insie the tank, although its hard to understand why the stock pump wouldn't be working with a separate power supply.

 

I was thinking that, but when I tried my old pump (didn't try before because one of my upgrades was fuel pump) nothing. I was originally swapping an ls1 into the car, but I was able to sell the LS1. I kept the fuel pump I receieved with the LS1, and nothing.

So that's 3 pumps that when supplied 12V+ to the pump...nothing.

I tried the "red" prime connector by the PCM but nothing, and it just heated up the plastic around the connector..didn't melt it, just warmed it up.