no fuel... please help!!!!

[lost06]

I am not getting any action from my fuel pump after my swap. when i turn the key on, it doesn't do anything. but, if i jump the wires at the relay, the pump powers up.

Does this mean I have a bad relay?

BTW... My fuel gauge goes way past the full mark and my oil pressure gauge isn't plugged in.

[kerrige]

First thing check grounds and relays.

[lost06]

Couldn't find any open grounds so I should be good on that.

I was checking the voltage at the relay and had just under 12v at the positives. But the ground showed around 8v. I know that can't be right.

[MrHorsepowerLSx]

Use a " known good ground " i.e. battery, frame, under hood grounding tab, accessory bracket, etc.... then test all the (+) again, if you are getting power when checking the (+) with a (-) from the harness there is the possibility that a wire is rubbing against another wire. Try this as well get a volt meter and clamp the black wire to the neg. battery and use a jumper and connect the pos. wire to a different ground lug ( back of motor, back of firewall, etc... anywhere there is another ground terminal ) if you are getting (+) from any other grounds, trace the wires back and find where they are rubbing though and touching the bare metal

[lost06]

Thanks Mr HP. Ill try that this evening and post the results.

[lost06]

Ok. here is what I have come up with... I decided to snip the strange blk /wht ground wire that has power and ground the relay to the frame. And when I turned the key on.... BAM we have a working fuel pump!!!! Buuutttt... when I went to start it, I wont crank anymore. So I re-connected the wire and it will crank, but no fuel pump.

So, I decided to chase the black wire to see where it goes. It went to a bundle of other blk/wht grounds so I'm stumped.

I also found that the red wire (relay pin #87a) has a black plug on the end of it that was sticking out of the wire loom. I don't see any other single wires that could go into it. What the hell is this for? Am I supposed to put power to it?

Here are pics of the mysterious red wire and the bundle of grounds. Also a generic diagram of the wires in the fuel pump relay.

20121205_172550.jpg
2012-12-05 19.30.41.jpg
S Memo_01.jpg

[lost06]

So I solved the problem, it was really simple. I grounded that set of grounds to the coil bracket on the valve cover. Apparently, this is a bad idea. I moved the ground to the alternator bracket and my gauge started working and the pump kicks on. I still sdont know why my test light was showing voltage....

Now, my truck would crank over BEFORE i would ground the fuel pump relay. Now it won't crank. I had an issue where the PRNDL switch wasn't allowing it to crank. I bought a new one and it fixed that problem. Now since I fixed the fuel pump.... it wont crank again...