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Carb or Fuel pump problem?

Discussion in 'The Garage' started by mountainexplorer, Oct 20, 2002.

  1. mountainexplorer

    mountainexplorer 1/2 ton status

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    I have 454 in my Suburban with a newer Edelbrock Carb. Before the Edelbrock, I had a Carter AFB. Both these carbs ran excellent on the other motors they were on (they would fire right up after sitting). Both carbs on this motor act the same way. It just takes forever to fire, especially after sitting over a couple days.

    Could it be the fuel pump allowing the fuel to leak back down from the carb?
     
  2. GMslave

    GMslave 1/2 ton status

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    What kind of fuel pump do you have? The carbs should have fuel in the float bowls for at least a day or two after running. But, if you're letting it sit longer and with a whipped out stock pump, ther ya go. Get yourself one of them Holley Mechanical, or Carter HV pumps. Mine sat all summer but fired up after only 30 seconds or so.
     
  3. mountainexplorer

    mountainexplorer 1/2 ton status

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    It's just a stock fuel pump that was on the motor when I put it in. Even if I drive it every day, it will usually fire, then die, then I'll have to crank it over several times before it fires again. The other big blocks I have seem to have a larger looking reservoir on the fuel pump. This looks to be the same size as a Small block pump.
     
  4. GMslave

    GMslave 1/2 ton status

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    Fuel pumps are cheap, I'd get a HV one and replace it. It sounds like you may have a crack or little pinhole in the diaphragm allowing the fuel to leak back down. The initial fire would suck the float bowl dry,then the little pump doesn't get enough ooomph to fill it back up fast enough. I'd bet that it's not feeding the carb all it wants in the upper RPM's/high load either.
     
  5. mountainexplorer

    mountainexplorer 1/2 ton status

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    Sounds like that could be it. It doesnt cut out or anything at higher RPM's, but for the built motor it is, I've always thought it should have more power than it does. Plus, it's always had a slight hesitation/miss after it warms up, and has acted that way with 3 different carbs.
     
  6. GMslave

    GMslave 1/2 ton status

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    Bingo. I wouldn't expect some HUGE horsepower gain, but I bet if that's it, you'll feel it. "Hello, Summit Racing??". BTW, nice pics.
     

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