GM B-Body Forum, 77-79 Caprice/Impala Forum

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GM B-Body Forum, 77-79 Caprice/Impala Forum

A forum for all the owners and enthusiasts of General Motors B-Bodies from 1965-1996, but dedicated to the owners of 1977-1979 Impalas and Caprices. Join up now!

    TBI to carb

    Robby Rob

    Posts : 1
    Join date : 2017-07-14

    TBI to carb Empty TBI to carb

    Post  Robby Rob on Fri Jul 14, 2017 12:18 am

    Doing a TBI to carb swap got the coil in cap distributor, bypass regulator and I need to know what wires to jump to get the fuel pump working
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    Auto Novice

    Posts : 93
    Join date : 2015-04-26
    Location : Northeast Ohio

    TBI to carb Empty Re: TBI to carb

    Post  Kit1078 on Sat Jul 15, 2017 9:14 am

    There are two ways I've seen to do this. First is to run a tach signal wire to the original computer so that it'll close the fuel pump relay when it sees the engine running. I've not tried this, so I can't tell you if it actually works.

    The second way (the one I'm using) is to plumb an oil pressure safety switch (like this one ) into the oil pressure sensor port on the block. I just put a tee back where the oil pressure sensor is under the distributor. This switch will be closed when there is more than 5lbs of oil pressure. You run ignition power to the 'I' terminal, then run a wire from the 'P' terminal to your fuel pump relay. You 'can' run this directly to the fuel pump, without a relay, but it tends to overload the switch and burn it out quickly. There is also a third terminal marked 'S' that can be wired to the starter solenoid so that your pump will run while you at cranking the starter.

      Current date/time is Sat Apr 04, 2020 9:49 pm