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Virtual Wrench
Virtual Wrench, Chevy Mechanic
Category: Chevy
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Experience:  35 years Master Mechanic
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Chevrolet C3500 4x2: 2001 Chevy 3500, Big block 8. This has

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2001 Chevy 3500, Big block 8.
This has a small gas tank. The fuel gauge does not work much at all below 50% when above 50% it jumps up and down. I'm thinking the sender in the tank is faulty. Any other ideas?


That is by far the most common reason for this to happen. You will need to pull the fuel pump module out and connect the connector back on then slowly move the float and watch the gauge. If it moves from empty to full when moving the float you know the gauge is good. We replace far more sending units than gauges for this type issue.


Customer: replied 4 years ago.

Whats it like removing that. Haven't looked yet. Have to drop the tank?

Hi Steve,

Yup, you guessed it. You have to drop the tank but its not so bad providing its close to empty. I dont think i have step by step instructions for it but will check real quick. Be right back.
Customer: replied 4 years ago.

it is full


You will either have to run it lower or try to siphon/drain it which isn't real easy.

Here is what i have for instructions.

  1. Disconnect the negative battery cable.
    NOTE Clean the fuel and EVAP connections before disconnecting them to prevent fuel system contamination. Cap the lines to prevent leakage and contamination.
  2. Relieve the fuel system pressure.
  3. Drain the fuel tank.
  4. Remove the fuel filler pipe and remove the tank shield, if equipped.
  5. Label and disconnect the EVAP lines and electrical connection from the fuel tank assembly.
  6. Disconnect the fuel line from the tank.
  7. Support the fuel tank using a suitable jack. Remove the strap bolts and the straps.
  8. Lower the tank halfway. Be sure the fill neck does not get hung up on the chassis harness. Detach the harness clip from the crossmember.
  9. Lower the tank enough so that the electrical connections are accessible. Detach the connections then fully lower the tank and remove it from under the vehicle.

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Customer: replied 4 years ago.

Can I not do it with a full tank? I have the support to lower it full? What issues will that cause if the tank is full?

Sure you can. Its just the weight thats a concern.

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