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Greg A
Greg A, Master Troubleshooter
Category: Cadillac
Satisfied Customers: 8852
Experience:  Working with Electronics & Cars for 25+ Years
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2001 deville gas gauge not working already tried additive

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2001 deville gas gauge not working already tried additive

Hello & Welcome,


Can you tell us how the gauge is behaving?



Customer: replied 8 years ago.
it randomly moves but dosen't show the correct amount of fuel. I've been using the gallons used to determine the fuel level

Hi again & thanks for that information.


Probably 95 percent of the time, the problem is the fuel level sender itself. I have a 2001 GM vehicle that had the same problem just last year. The fuel additive is a good idea, but what usually happens (like in my vehicle) is that the little metal "fingers" on the fuel sender get weak, bend, and break. There are 3 fingers on the sender so when one of them breaks it makes a good connection every now and then and will appear to work, then it goes bad again as the sender moves.


There are some tests that can be done to verify the rest of the system, but you will most likely find that the sender is bad and needs to be replaced. You may be able to replace the level sender separately from the fuel pump assembly, but it wouldn't be a bad idea to just replace the whole thing at one time. It will most likely involve dropping the fuel tank to replace it.


I hope this helps. Please let me know what you decide to do.


Take Care, Greg A.

Customer: replied 8 years ago.
I found the access port in the trunk to get to the fuel pump, any tricks I need to know on replacing it

Hi again - sorry for the delay.


Let me check the procedure and see what it says.


Back soon, Greg A.

Customer: replied 8 years ago.

Hi again,


Here is the procedure, which look pretty straight forward. You might want to print this out and read it over a couple of times before you being.


Fuel Sender Assembly Replacement

Removal Procedure


Fuel Vapors can collect while servicing fuel system parts in enclosed areas such as a trunk. To reduce the risk of fire and increased exposure to vapors:

  • Use forced air ventilation such as a fan set outside of the trunk.
  • Plug or cap any fuel system openings in order to reduce fuel vapor formation.
  • Clean up any spilled fuel immediately.
  • Avoid sparks and any source of ignition.
  • Use signs to alert others in the work area that fuel system work is in process.



  1. Relieve the fuel system pressure.
  2. Drain the fuel tank.
  3. Remove the rear compartment trim panel.
  4. Remove the fuel sender access panel bolts.
  5. Remove the fuel sender access panel.


    In order to prevent damage, cover the fuel pipe fittings with a shop towel before disconnecting the fuel pipes or removal of the fuel sender retaining ring, in order to catch any fuel that may leak out. Place the towel in an approved container when procedure is completed.


  6. Disconnect the fuel sender quick-connect fittings.
  7. Disconnect the fuel sender electrical connector.
  8. Disconnect the fuel tank pressure sensor electrical connector.


    The modular fuel sender assembly will spring-up when the locking ring is removed.


  9. Remove the fuel sender retaining ring using the fuel sender lock nut wrench.


    Do Not handle the fuel sender assembly by the fuel pipes. The amount of leverage generated by handling the fuel pipes could damage the joints.



    When removing the fuel sender assembly from the fuel tank, the reservoir bucket on the fuel sender is full of fuel. The fuel sender must be tipped slightly during removal in order to avoid damage to the float. Place any remaining fuel into an approved container once the fuel sender is removed from the fuel tank.


  10. Remove the fuel sender assembly.
  11. Clean the fuel sender sealing surfaces.
  12. Inspect the fuel sender sealing surfaces.

Installation Procedure



    Care should be taken not to fold over or twist the fuel pump strainer when installing the fuel sender assembly, as this will restrict fuel flow. Also, assure that the fuel pump strainer does not block full travel of the float arm.



    Always replace the fuel sender seal when reinstalling the fuel sender.


  1. Position the new fuel sender seal on the fuel tank.
  2. Install the fuel sender assembly and the fuel sender lock ring using the fuel sender lock nut wrench.
  3. Connect the quick-connect fittings at the fuel sender.
  4. Connect the fuel sender electrical connector.
  5. Connect the fuel tank pressure sensor electrical connector.
  6. Add fuel to the fuel tank.
  7. Install the fuel tank filler pipe cap.
  8. Connect the negative battery cable.
  9. Perform the following procedure in order to inspect for leaks:
    1. Turn ON the ignition, with the engine OFF for 2 seconds.
    2. Turn OFF the ignition for 10 seconds.
    3. Turn ON the ignition, with the engine OFF.
    4. Inspect for fuel leaks.

  10. Install the fuel sender access panel.


    Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.


  11. Install the fuel sender access panel bolts. Tighten

    Tighten the fuel sender access panel bolts to 2 N·m (18 lb in).

  12. Install the rear compartment trim panel.

I did check and it says that you can replace the sensor separate from the fuel pump, but the choice is yours on that.


Please let me know how it goes.


Take Care, Greg A.


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