Fuel pump re-wire

  • #1

    Fuel pump re-wire

    Running a hard wire from the battery to the fuel pump. Have an inline fuse for protection. Have a bosch 044, after probably a year of light use the inline fuse melted to the fuse. Very hot when I run it, the normal hot wire itself is not. Going to replace it and see how it goes but has anyone else experienced this and how did you fix it. Last thing I want is an electrical fire.
    Usual Z31 suspect: Garage Queen (aka broken)
  • #2
    Are you using a relay?
  • #3
    For the ground wire, yes.
    Usual Z31 suspect: Garage Queen (aka broken)
  • #4
    hmmmm....I'm running the 044 as well and (knock on wood) haven't had any problems yet. I wish I had a better answer for you.
  • #5
    What AMP fuse are you running and what gauge wire?
  • #6
    Also did you reuse the stock fuel pump wiring on the OE fuel pump cage? The terminals on top very often corrode and produce an unacceptable amount of resistance. From what I recall the 044 pump *shouldn't* pull more than like 12 amps (don't quote me on that, but it wasn't a ton of amperage IIRC)
  • #7
    All new wiring, 20 amp fuse. 10 gauge wire. The fuse melted on itself so I'm assuming it was a bad old fuse.
    Usual Z31 suspect: Garage Queen (aka broken)
  • #8
    plausible....change it and see what happens. Also run a check to see what the amperage draw is, just for shits
  • #9
    I'm assuming you were drawing straight from the battery?

    I ran the exact set-up, but switched over to ECU to trip the hot side of the relay - don't really fancy burning to death in a roll over.

    Never had a problem, but you can go to a smaller gauge wire safely.

    Assume it was a junk fuse.. or check your ground points, it needs to be raw metal.
  • #10
    Ah, could be ground point. Will sand it down and re attach.
    Usual Z31 suspect: Garage Queen (aka broken)
  • #11
    If you switch the ground with a relay, it shouldn't heat up as much as doing on the hot side…
  • #12
    Originally posted by G-E View Post
    If you switch the ground with a relay, it shouldn't heat up as much as doing on the hot side…
    That's what I thought. Also how would switching the hot side with the relay be any different? If the car rolls over the ECU is still giving ground signal to turn on the pump, which in turn the hot side will still be giving power? Maybe I'm confused how you have it hooked up.
    Usual Z31 suspect: Garage Queen (aka broken)
  • #13
    You need the heavy gauge wire for the main hot to the pump, because that's what normally burns out with the high-draw newer pumps, what you don't need to do is upgrade the ground

    The OLD hot can power the relay, so you get power to that as normal, and you reallocate the old pump ground to the relay switch ground, which is still controlled by the ecu -- this disabled the ecu from varying voltage to the pump, but still controls the on/off

    You can ground the pump through the relay to the chassis if you have a good spot in the back, or run a ground wire back up to the front, probably to a nexus of grounding points like the firewall