Jammin'Trey

hey guys I am trying to run my fuel pump on a switch, I run 12v to the relay (farthest grey wire) but it will not run the pump. When I hook it up stock it works fine but I cannot prime my fuel system. I live on a hill nd this switch is a must.

jeffcj

iTrader: (3)

I realize your car is no longer computer controlled, but maybe this will help.

Damon

To the stock FP relay? I think the relay is controlled by 2 things, not just one. If memory serves the hot side is supplied from the ignition key but the ground side is controlled by the ECM. I'm talking the low-draw activation circuit side of the relay here, not the high amp power supply side that actually powers the pump.

I always left my ECM in place, even after conversion to carb so I could still get that 2 second key-on pump prime that's built into the computer's programming.

scottkb1975

Damon makes a good point. Something tells me you have it in place though due to the relay still running the pump. So when you turn the key on it should prime if not you got a bad relay.

HottestZ28

The stock Relay runs through a 2 grounds not power. I just tried to hook it up in my application and it wouldn't work . I then bought a 5 pin relay and wired it up like factory other then finding a Key-On power source to activate the relay and works perfectly. When I turn the key to Acc it primes the pump and has enough pressure to start.
Use the factory 12+
factory ground
run a wire from the relay to the power wire to the pump
Find a wire that powers up with key on
the 5th pin you don't have to use