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  1. #1
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    Default Fuel Pump Wiring

    I'm converting to a carb setup and need help finding the power wire for the fuel pump to wire it to a switch or keyed ignition. Can someone tell me which wire it is? I found the diagram for the fans on shbox website, but can't seem to find anything for the fuel pump.

  2. #2
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    Default

    I was able to find this pic for the fuel pump relay location, but still need to know which wire powers the relay/pump.

    http://shbox.com/1/fuel_pump_relay.jpg

  3. #3
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    Quote Originally Posted by greenz28 View Post
    I was able to find this pic for the fuel pump relay location, but still need to know which wire powers the relay/pump.

    http://shbox.com/1/fuel_pump_relay.jpg
    Ok, I think I found what I was looking for in post #19. I'll leave this thread here for updates incase anyone else needs it.

    https://ls1tech.com/forums/conversio...-no-start.html

  4. #4
    Asshole.


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    Default

    Looks like you found your answer. I was probing all of these wires to troubleshoot a failed Racetronix pump on my car just a few weeks ago. The gray wire in the back of the car, relay, connector under the dash, etc. I ended up buying a new pump and it magically started working. Imagine that.

    Chris.
    1994 Trans Am
    Under the knife - who knows when it'll run (5.3 LM7/CPT 60e/QP 9")
    2009 Corvette Z06 HCI, Coilovers, 630whp | 1987 Iroc Sitting in the weeds | 2006 Silverado Z71 5.3 "HO" L33/60e, Baby cam'd at 240k and top end refresh, still going strong!

  5. #5
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    Default

    Fuel pump relay gets 12 volt control sIgnal from PCM. If you are deleting the PCM you need to supply 12 volt switched power to terminal 85 of the relay. Shoebox PCM diagram:

    http://shbox.com/1/1995_pcm3.jpg

    94 Formula A3+1: 381ci forged stroker - Callies Stealth, Oliver 5.85 billet rods, BME nitrous pistons / CNC LT4 heads / Comp Cams solid roller / TH400+GearVendors OD / 4.11's/Strange 12-bolt / 300-shot (dry) N2O / Spohn Suspension / 6-pt roll bar /AutoMeter instrumentation / MoTeC M48 Pro engine management system /a few other odds 'n ends.

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  7. #6
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    Default

    Perfect, thanks!

  8. #7
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    Quote Originally Posted by harner View Post
    Looks like you found your answer. I was probing all of these wires to troubleshoot a failed Racetronix pump on my car just a few weeks ago. The gray wire in the back of the car, relay, connector under the dash, etc. I ended up buying a new pump and it magically started working. Imagine that.
    So, it started working before or after the new fuel pump install?

  9. #8
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    Quote Originally Posted by greenz28 View Post
    So, it started working before or after the new fuel pump install?
    New fuel pump and it started working.

    My car is an LS swap with a custom plug and play BP Automotive harness that has been sitting around for years. So when there was no pump with key on and not being able to force it to prime with HP Tuners, I had to probe the harness. Started with the prime connector by the PCM under the hood, then the connector under the dash on the PS, relay, and started probing the gray wires in the Racetronix hotwire harness. I even probed the pump itself after ripping it out of the tank. $150 later, a new pump fixed it, but all of the testing was necessary due to all of the aftermarket components. Not too relevant to this thread, but feel free to check out my build thread if you're interested.

    Chris.
    1994 Trans Am
    Under the knife - who knows when it'll run (5.3 LM7/CPT 60e/QP 9")
    2009 Corvette Z06 HCI, Coilovers, 630whp | 1987 Iroc Sitting in the weeds | 2006 Silverado Z71 5.3 "HO" L33/60e, Baby cam'd at 240k and top end refresh, still going strong!

  10. #9
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    What year is your chassis? The 93-95 uses the wiring diagram shown in the Shoebox schematic, with a 4 terminal relay. The 96/97 uses a 5 terminal relay and the wiring is slightly different, due to the prime connector wiring passing through the relay, instead of bypassing it. In both cases, the 12 volt switched power goes to terminal 85.

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  12. #10
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    Quote Originally Posted by Injuneer View Post
    What year is your chassis? The 93-95 uses the wiring diagram shown in the Shoebox schematic, with a 4 terminal relay. The 96/97 uses a 5 terminal relay and the wiring is slightly different, due to the prime connector wiring passing through the relay, instead of bypassing it. In both cases, the 12 volt switched power goes to terminal 85.
    It's a 94.

    Another question while I have your attention: For the starter solenoid, can I use the factory wire and just bypass the security relay behind the glove box? Also, I assume the Shoe Box manual fan switch diagram will work for me if I use the pcm controller wires and tap them into a keyed 12 volt source? Thanks again!

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