Fuel system wiring trouble
10-15-2014, 09:19 PM
#1
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Car: 86 Z28
Engine: '06 LQ4
Transmission: GTO T56
Axle/Gears: 3.73 S60
Fuel system wiring trouble
I'm finishing up swapping an LQ4/T56 into my 86 Camaro. My car was originally carbureted, so I installed a fourth gen plastic fuel tank and a racetronix hotwire kit. With the fuel tank, I got the wiring harness from the tank to the chassis. I cut off the chassis-side connector and connected the black wire from the third gen chassis connector to the black wires coming from the tank. I connected the pink fuel level sender wire to the purple or pink wire from the tank. Then I connected the fuel pump trigger wire off my HP EFI system to the gray wire going into the tank. When I connect the efi system to the battery the fuel pump goes on and stays on regardless of whether the key is on or not. Holley seems to think its a wiring issue, but I'm not sure where I went wrong. Any help would be appreciated, thanks.
10-15-2014, 10:30 PM
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Car: 92 Firebird
Engine: Supercharged 6.0
Transmission: T56
Axle/Gears: 8.8 3.73
Re: Fuel system wiring trouble
It is a wiring issue. The system need to trigger the FP relay, not the FP directly
Next, unplug the relay and try again. Might just be stuck closed
Next, unplug the relay and try again. Might just be stuck closed
10-16-2014, 12:01 AM
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Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Fuel system wiring trouble
There were two RED wires in the Holley harness that you were supposed to run to switched power sources. I suspect those have constant power. The slightly larger wire is the power source for the fuel pump (which in your case simply operates the Racetronix relay).
10-16-2014, 01:07 AM
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Car: 86 Z28
Engine: '06 LQ4
Transmission: GTO T56
Axle/Gears: 3.73 S60
Re: Fuel system wiring trouble
There is a red wire that powers the injectors and fuel pump and a separate wire that goes directly to the computer. The wire that powers the fuel pump and injectors is what's causing the fuel pump to stay on, but when I was on the phone with Holley the guy assured me that it is supposed to connect directly to the battery, and that my relay is bad. I attached the wiring diagram for the ls1 harness, and it does say 12V battery, I'm just not sure how that would work without constantly running the pump.
10-16-2014, 08:42 AM
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Car: '89 Firebird
Engine: 7.0L
Transmission: T56
Re: Fuel system wiring trouble
Well, all I can tell you is that I'm running that to switched power no matter what the Holley guy says.
You can check the relay for welded contacts. Pull out the relay and measure continuity across the pins that the two larger wires go to. It should be open circuit.
It's also possible that Holley wired the relay wrong. I think it can be wired for either closed normal, or open normal. I know my own HP harness was made by retards. I've had to do a ton of rework to it.
You can check the relay for welded contacts. Pull out the relay and measure continuity across the pins that the two larger wires go to. It should be open circuit.
It's also possible that Holley wired the relay wrong. I think it can be wired for either closed normal, or open normal. I know my own HP harness was made by retards. I've had to do a ton of rework to it.
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