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fuel pump voltage

Discussion in 'The Injection Section' started by RAY, Aug 5, 2017.

  1. RAY

    RAY 1/2 ton status Premium Member

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    Trying to diagnose if a bad pump is the reason why my fuel pressure is so low (8 psi) on my tbi conversion. I am showing 8V at the pump pigtail back by the tank and framerail when I cycle the key on and off. Is this too low? I have also tried connecting my jump starter pack to the fuel pump which is putting out 13V, but I get no change in the pressure at the throttle body with the higher voltage. This is on a stock 350 that I am converting from carb to TBI.

    Thanks,
    Ray
     
  2. 1-ton

    1-ton 1/2 ton status Premium Member

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    Actually 8-PSI is normal for a stock TBI unit. It takes an adjustable fuel pressure regulator to get any much more higher than about 9-PSI. I know there are some people that think that stock TBI units are supposed to be up around 11 or 12 PSI. The stock TBI pump may be able to go up to 11 or 12 PSI, but that is not the reality of what GM designed the fuel regulator to operate at.
     
  3. bent72

    bent72 Desert Solitaire Premium Member GMOTM Winner

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    Should be 12v
     

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