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Grounding problem on fuel pumps

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Old Jul 15, 2018 | 02:50 PM
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Default Grounding problem on fuel pumps

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?

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Old Jul 16, 2018 | 06:25 AM
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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.
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Old Jul 16, 2018 | 11:20 AM
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Not sure which ecu you have but some complete the ground circuit, thus grounding the ecu allows the circuit to close.
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Old Jul 18, 2018 | 04:04 PM
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stock ECU sends 12v to activate fuel pump relay
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Old Jul 18, 2018 | 06:52 PM
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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.
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