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  1. #1

    Default No power to fuel tank

    I have a 99 chevy z 71 5.3 liter. All my fuses and relays are good and i put in a new fuel pump, but still have no power to fuel tank . When i hook scan tool to hook up under dash it tells me no connection. Please help i need my truck. Thanks

  2. #2

    Default

    Power to the scanner and power to the pump are 2 completely different things, check the inside and all fuses and check to see if your cig lighter/ power outlets work.
    01' 1500 LT Z71 ECSB 5.3L
    line-x'd front brush guard with KC Daylighters, 6000k HID lows and highs, rewired highbeams, Trans-go mild shift kit, custom stainless duals, 3500 dually OEM taillights, K&N CAI. Still have OEM fender flairs and leveling kit in boxes waiting for time.


  3. #3

    Default

    It's a simple circuit, so I am going to ask some dumb ass questions.

    - how do you know all fuses are good?
    - how do you know the pump relay is good?
    - how do you know (other than what you said in the 1st post) that there is no power to the pump (perhaps you have 12v and you do not have a ground?
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  4. #4

    Default

    Also is it no power to the scanner or no communication because a dead computer or no power to it can cause both of those probs. Too vague here we need more info.

  5. #5

    Default

    Been through all fuses and relays and replaced them still no power with connectors hooked up at the tank. The scan tools says no communication.

    - - - Updated - - -

    Truck cranks, oil pressure comes up, all gauges work, but fuel gauge sits on E. Speedo was maxed but back to zero now agter disconnecting battery

  6. #6

    Default

    I would check all my ground wires. I had a 96 and ended up replacing all ground wires, and I do mean all ground wires. Even the one to the fuel pump on the frame. That fixed all my problems. i had the same symptoms except the no communication for the obdII. Also if i'm correct you will only have power to the pump for a few seconds when you turn the key on unless the truck is running. Just throwing things out there.

  7. #7

    Default

    Thanks im gonna start chasing n replacing wires. If ya think of ne thing else please let me know. Thanks again.

  8. #8
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    Default

    Quote Originally Posted by JePride33 View Post
    Been through all fuses and relays and replaced them still no power with connectors hooked up at the tank. The scan tools says no communication.

    - - - Updated - - -

    Truck cranks, oil pressure comes up, all gauges work, but fuel gauge sits on E. Speedo was maxed but back to zero now agter disconnecting battery
    remove the fuel pump connector and measure the voltage .then work back to the fuel pump fuse for voltage then the fuel pump relay .

    connect a pressure gauge on the fuel rail when doing the voltage tests .

    scan tool no communication with power at the scan plug could mean the PCM is blown.

    if the key was in the ignition when the battery was disconnected this could blow fuses and the PCM..

  9. #9

    Default

    Thanks for all the info. It turns out it was the ECM B fuse.

  10. #10

    Default

    FFFFFUUUUUUUUSSSSSSSSSEEEEEEEEEEEEESSSSSSSSSSSS!!! !! Happens to the best of us.

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