My fuel pump relay acts up once in a while and I need to straighten it out. The pump will not turn on when I start the car sometimes. The car will only start after cranking it for about 5 seconds. I dont wanna do this with my new engine since I am running a lot of fuel into it. I think its one of the contacts inside the relay or the connector under the relay because if I mess with it, the car will start up. Im thinking of just rewiring the entire fuel pump circuit. I am running a Holley intank pump and I know it works overtime back there with the stock crappy wiring. Plus I have some decent audio gear in my car now so I would like to upgrade the wiring for the fump pump and relay. Has anyone rewired their fuel pump with larger gauge wiring and noticed a voltage increase back there? 90% of the cars wiring is gone now so I would like to get rid the last remainng junk and start with fresh wires. What gauge should I use? also, my relay ground is now hooked up into my F.A.S.T ECU. if that matters. The ECU has a black wire labled fuel pump -.

 

Use at least AWG12 for an aftermarket fuel pump - That includes the ground wire for the pump. Try cleaning the relay socket contacts, reject the contacts from the socket and make sure they have adequate spring to maintain good connection, and be sure the contacts are solidly crimped to the wires. As long as the contacts are out of the socket, you might as well solder them to the wires instead of relying solely on the crimp.

If you suspect the relay itself, either open the relay can and check the contacts or replace the relay.