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External fuel pump wire gauge.

Discussion in 'The Garage' started by Hossbaby50, Feb 27, 2004.

  1. Hossbaby50

    Hossbaby50 3/4 ton status

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    I am wondering if I need to run a heavier gauge wire to my fuel pump. I am currently running 14 gauge wire all the way to the back of my truck where the pump is located. So I am running the fuel pump power from the firewall down to the frame all the way back to the rear tires or so.

    Should I rewire with 10 gauge? I recently picked up some 10 gauge for nothing so I have the wire.

    You can hear my fuel pumps output increase and decrease with the output of my alternator. When the motor is running more RPM and the alt is pumping more amps the fuel pump runs stronger, when the alt speed drops the fuel pump does too. Thanks

    Harley

    P.S. the alt is reading fine on the volt gauge. 14 volts or so of output.
     
  2. BobK

    BobK 1/2 ton status

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    I'd say 14 g is a little small.
    Is this a factory pump?Factory wiring?

    When I did my TPI swap I ran a 12g wire from my relay to the electric pump.I don't hear any flucuations in the pump at any eng. rpm.

    10-12g should be fine for an e-pump.
     
  3. Hossbaby50

    Hossbaby50 3/4 ton status

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    It is an aftermarket MSD MPFI pump. I will go ahead and rewire it soon. I have the wire so it is no big deal. I actually might do it in 8 gauge since I have that laying around too.

    Harley
     
  4. CyberSniper

    CyberSniper 1/2 ton status Premium Member

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    You're taking power off the battery through a relay, right? I think I remember you saying you did back in the day.

    At 10 amps, which your fuel pump shouldn't take more than even just before cavitating (peak load), you'll lose about a volt on 20' of 14 gauge THNN. At 10 gauge you'd lose like half a volt. If it's not too much of a chore I'd do it.
     

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