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Thread: TBI fuel pump, can fuel be drawn thru it unpowered?

  1. #1
    Carb and Points! kilohertz's Avatar
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    TBI fuel pump, can fuel be drawn thru it unpowered?

    Hi guys,

    Mounting a new fuel tank and pump in my 49 F-47 truck and want to know if I can draw fuel thru an un-powered in tank TBI pump for the carb until I get the TBI system built. The tank and pump are from an early 90's GM van. Will a mechanical pump for a carb be able to draw gas thru the pump?

    Thanks
    Last edited by kilohertz; 1 Week Ago at 07:07 AM.

  2. #2
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    This doesn't usually work well. There is usually too much restriction in the flow path for the mechanical pump to supply enough fuel. YMMV.

  3. #3
    Carb and Points! kilohertz's Avatar
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    Okay, thx for the reply. My box is off now so I can at least try it, if it doesn't work I can remove the pump and just put a drop tube in for now...still sourcing parts for my TBI setup.

    cheers

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    Would it make sense to wire in the electric pump now and use it to feed the carb?

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    Carb and Points! kilohertz's Avatar
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    Quote Originally Posted by 1project2many View Post
    Would it make sense to wire in the electric pump now and use it to feed the carb?
    It would, except the pump puts out 25PSI and then I would need to buy a regulator and mount it somewhere. Carb needs about 3-5 PSI.

    Cheers

  6. #6
    Electronic Ignition!
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    I do use an electric pump (low pressure )to push through the mechanical.

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    Quote Originally Posted by kilohertz View Post
    It would, except the pump puts out 25PSI and then I would need to buy a regulator and mount it somewhere. Carb needs about 3-5 PSI.

    Cheers
    Understood. The price of an aftermarket regulator can be quite high.

  8. #8
    Fuel Injected!
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    Don't know the exact specifics but a friend of mine on his late '80s C4 TPI converted to carb...used the stock in tank fuel pump. At the carb end, all he did was run a t-fitting with a nitrous pill stuffed in the rubber hose that goes to the return line. I asked what size and was told "trade secret."

  9. #9
    Fuel Injected!
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    Quote Originally Posted by 1project2many View Post
    Understood. The price of an aftermarket regulator can be quite high.
    $50 for quick fuel regulator $60 for holley regulator on amazon. prices in canadian dollars.....

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