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Thread: Electric Fuel Pump Wiring

  1. #11
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    I'm not sure what's meant by "don't run an electric pump deadheaded". If the pump is making the desired pressure when the engine is running, it has the same load on it that it would if "deadheaded". Doesn't matter what the engine's fuel demand is. You need a pressure regulator and it will always regulate the pressure to what it's set at. Pumps also have a relief valve built in to protect against true deadheading. As an example, the trusty old Holley "blue" pump is used with a pressure regulator (actually it's a pressure reducing valve with no bypass). But the blue pump has a pressure relief valve built in it.

    As for the safety switch, there's another setup you can consider. It's called a "rollover switch", if the car rolls it cuts power to the fuel pump. Some, maybe all, Fox body Mustangs had them. I'm sure many others too, but that's the one I know of.

    If it was my car, I'd wire the fuel pump with a relay. The relay would be activated with the ignition switch in cranking and run positions. Using a relay minimizes the electrical load on the switch, and lets you run a 12-14 gauge wire for the pump from the battery to the relay and from the relay to the pump.

    I would not run a "hybrid" system with both an electrical and a mechanical pump. Choose one, either a mechanical pump or an electric pump. Do the electric pump installation correctly, with gravity feed. Don't use the stock pickup for an electric pump, as electric pumps don't make much suction. An in tank pump would be the best way to do this for a street driven car, because most of the other solutions have plumbing hanging below the tank which is not good for the street, as it could get damaged (safety again). Don't use the drain fitting in a stock tank as it's only 1/8" pipe, not big enough for a BBC, or a healthy SBC.

    On the other hand, there is nothing wrong with a properly operating mechanical pump which uses the stock type pickup. But Tony won't admit there's something wrong with his because he can't/won't find the problem and fix it.

  2. #12
    Registered Member chasracer's Avatar
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    It's actually rather simple and I believe one of the reasons that car manufacturers do not run their electric pumps "dead-headed". This does not have anything to do with whether the pressure is high, low or in-between. If we have a pressure port fuel regulator in the system, that regulator is constantly opening and closing as the engine uses fuel. During those closed periods, the pump is pushing fuel against the regulator that is basically going no where. This puts additional heat into the fuel pump and in turn there is some additional wear on the pump mechanism itself. Again, I have run pumps dead-headed in the past, they last a few years but that same pump put into a return system where there is less heat and work for the pump will last a hell of a lot longer. It can also reduce some load on the electrical system although that may be very marginal. We have used Holley, Barry Grant, Aeromotive and Magnafuel - they all eventually fail in a dead head situation. My preference is simply to provide a fuel "loop" from tank back to the tank, then using a bypass type regulator, pull off the fuel from this loop that my engine combination requires. I currently have an Aeromotive pump that is on it's 12th year in a loop system. Oh and one other minor detail, the fuel itself will also be just a bit cooler in the whole process.

  3. #13
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    Quote Originally Posted by Rick_L View Post
    But Tony won't admit there's something wrong with his because he can't/won't find the problem and fix it.
    Rick, you gave me a good LOL! Don't forget, there must have been something wrong with the previous pump also, it did the same thing.

    Are you up to the $1000 challenge? Come on, I could use the money.
    Tony

    1955 Bel Air Sport Coupe

  4. #14
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    No I want to be the judge, and I'll sell the tickets to the show too.

  5. #15
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    No takers and I already took out the mechanical pump so forget selling tickets. I get the feeling that if this works no one will believe it.
    Tony

    1955 Bel Air Sport Coupe

  6. #16
    Registered Member chevynut's Avatar
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    Tony, after watching that video I posted I believe you . I never realized that gas could boil at such low temps. I still think it would have been interesting to see if the problem went away with the electric pump pushing gas to the mechanical pump....but in the video they say that won't solve the problem.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


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  7. #17
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    Hey Cnut did you see the part about avoiding corn gas.

  8. #18
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    Quote Originally Posted by markm View Post
    Hey Cnut did you see the part about avoiding corn gas.
    I did. And I'll tell you that the butane in the gas has a far far greater impact on the boiling point then ethanol. But since I don't own a speed shop, you probably won't believe me.
    Tony

    1955 Bel Air Sport Coupe

  9. #19
    Registered Member chevynut's Avatar
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    Quote Originally Posted by markm View Post
    Hey Cnut did you see the part about avoiding corn gas.
    Only if you're still running a POS carburetor and a low pressure fuel pump. It works great with EFI that most cars use these days.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  10. #20
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    My 2013 Tahoe police pursuit hauls ass on E-85. It's a good way to go on a high compression engine, when building a whole new fuel system setup on a hot rod. If I could do it all over on my Camaro LT-1, I would for sure go with a FI carb, and all the hardware setup to run on E-85. Just can't justify a couple grand to re-do all old school stuff that runs awesome on race gas blends, which is much cheaper in comparison.
    Last edited by 55 Rescue Dog; 03-12-2018 at 03:05 PM.

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