kward

iTrader: (1)

Can't figure this one out, building a 69 Camaro and updated the harness with a PCI engine harness and American Autowire update kit and the fuel pumps will only come on when you ground the computer. The harness is grounded to the head, frame and to a solid ground inside the body. Any thoughts on what to check next before I ruin the ECM?

forcd ind

iTrader: (7)

Never messed with a stock ECU, but sounds like a gnd. problem somewhere.
Is the bat. in the trunk? I had to run a gnd. from the bat to the front subframe,
subframe to engine-the mounts kind of insulate things from each other. Car
also started better.

Loud Mouse

Not sure which ecu you have but some complete the ground circuit, thus grounding the ecu allows the circuit to close.

oange ss

iTrader: (50)

stock ECU sends 12v to activate fuel pump relay

chiaj144

iTrader: (4)

What does your entire wiring system look like? Is your battery grounded to the engine? I ground my battery to the engine, engine to chassis and everything else fans, ecu, stereo to engine and my fuel pump to the battery as it's in the trunk.