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Customs electric fuel pump

Discussion in 'The Hokey Ass Message Board' started by lance8615, Mar 27, 2019.

  1. lance8615
    Joined: Mar 27, 2019
    Posts: 4


    I want to add an electric fuel pump to one of my collector cars. But I also want to do it safely and have a cut off switch in case of low oil pressure, accident, etc. If I use an oil pressure switch as a ground for the fuel pump, I'm guessing I'd want one that is "NO" normally open but would close when oil pressure is I have this straight? Does anyone know of a source for this type of safety switch? I believe the ones commonly used for oil pressure warning lights are NC normally closed which would be the opposite of what I want, correct? Any suggestions are most appreciated..thanks..lance
  2. tinkirk
    Joined: Jan 16, 2017
    Posts: 111


    You could probably tee in a NO switch
    Not a bad idea, experiment with it

    Sent from my iPhone using Tapatalk
  3. Just a guess here. I would think the ones for idiot lights are NO and then close to turn on the light. You would want one NC and then open to shut off the pump.
  4. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,104

    from WA-OR, USA

    For an electrical load such as an electric fuel pump it would be best to use the pressure switch to activate a relay to power the pump.

  5. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,390


  6. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,104

    from WA-OR, USA

    Here's one way to do it:

    I like to use a relay powered up from the pressure switch. I just use a normally open pressure switch that closes under oil pressure and switches to ground, energizing the relay (the other side of the relay coil is wired to positive). I run a wire from the pressure switch to a momentary toggle switch (that also switches to ground), for use as a manual prime/override. Using the ground to activate the relay keeps positive wires to and from the engine at a minimum, making things a bit safer.
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 50,261


    you could use a Standard Motor Products PS-64, and wire the S terminal to the starter wire, and the I terminal to the ignition, and the P terminal to the pump. then when starting the engine, it will run the pump, when the engine is running, it will run the pump, when the engine quits but the ignition is on, the pump will stop.

    I've been using this setup for a couple decades, seems to work. With a normal pump that draws less than 5 amps, no relay is necessary.
    tenlug likes this.
  8. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 9,003


    Could you also consider one of these inertia switches?

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