How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

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  • 1 Post By Submariner409
Cadillac Tech Tips - How to fix it Discussion, How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles in Item Specific Cadillac Discussion; My gas gauge was jumping up to full after the tank reached about 1/2. I learned to live with it ...
  1. #1
    Yaemish is offline Cadillac Owners Connoisseur
    Automobile(s): 02 Seville, 04 SRX
    Join Date
    Sep 2003

    How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

    My gas gauge was jumping up to full after the tank reached about 1/2. I learned to live with it and just watched my mileage but I figure that it is something that needed to be fixed. Thanks to the Aurora forum, I found that there was an easy and inexpensive fix that did not require you to purchase a new fuel pump.

    There are three little metal arms on the float arm and over time, these arms stop making contact where they register low fuel. With a little ingenuity, you can replace the arm with a $25 common AC Delco part. GM doesn't sell the sensor by itself, but they do sell a part for another car that has the arm that is used on our cars. The entire job can be done in about an hour.

    Parts Needed
    GM #15824379 This part comes with additional components, none of which will be used. We only need the small gray arm.

    Pump Removal
    1. Access the fuel pump located under the carpet on the passenger side of the trunk. You will need to remove the bottom carpet and spare tire.
    2. The are about five 7mm screws that need to be removed to reveal the pump.
    3. Try to relieve some of the fuel pressure (there is a pressure release under the hood). For me, it didn't make a difference and I still had pressurized fuel spray out. Make sure that you have a full size towel to catch the fuel. Shop rags will not be enough.
    4. Release the two pressurized fuel lines and use the towel to soak up the gas that is released.
    5. There are two electrical connectors that need to be disconnected.
    6. There is a special tool to twist off the plate that secures the pump to the body. This tool is expensive and not worth purchasing. I use a hammer and a brass chisel or punch to get the plate to spin off. If there is rust you may want to use to penetrating oil to loosen it up. Keep in mind that you have to use the brass chisel or punch as they will not spark. You are dealing with exposed gas so take the proper precautions.
    7. Use a shop vac and some damp towels to clean around the pump. You don't want any debris falling in there.
    8. Once you spin off the plate, the entire fuel pump will lift right out. Do it slowly and drain as much gas as possible back into the tank.

    Changing the Arm
    1. The part that we retrieve the arm off of looks like this.

    2. You will see a very similar looking part with the float attached to your pump. There are two electrical connections that need to be removed and then the plastic attachment part has a tab to release and slide off.
    3. Use a small screw driver and carefully remove the rigid wire that attaches the foam float to the arm. Here are the old and new parts to compare.

    4. Remove the gray arm from the new connector. I placed the plastic piece between two pieces of wood and then just used a punch to pop off the metal fastener and release the arm. DO NOT PRY IT OFF.
    5. Do the same thing to remove the old arm.
    6. Attach the new arm to the old connector and use the punch to put the metal faster back in. Remember, we only need the arm and none of the additional electronic sensor components as THESE WILL NOT WORK WITH YOUR CAR.
    7. Reattach the old part with the new arm to the pump.

    Reinstalling the Pump
    Everything goes back in just as it came out. This would be a good time to mention that you would be extremely lucky to be able to reuse the old pump seal. Its not going to work again. Do yourself a favor and pay the ~$20 to buy a new rubber seal. Otherwise you are going to get the "check gas cap message". I know its tempting to try and reuse the old one. You will drive yourself insane trying to get it together without getting that message. Just buy the new seal. You will have to buy it from a GM dealer or order it online.

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  3. #2
    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
    Automobile(s): White Diamond '03 DHS (with DTS floor shift)
    Join Date
    Jun 2004
    Woodstock Ill.

    Re: How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

    Copied to Tech Tips. Thank you.

  4. #3
    ronswanson's Avatar
    ronswanson is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Aug 2011

    Re: How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

    Same procedure for a 2004 deville?

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  6. #4
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS - 67,500 miles, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    MD Eastern Shore, Kent Island

    Re: How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

    Essentially, yes.

    Look at the pump assembly pictures - and the other embedded pictures - in several examples in RockAuto. You get to your year, make, model, system and click the small thumnbnail or the INFO tab and that opens a larger picture with others attached - one pump module even has a generic replacement YouTube video link.

    Your car may have an access hatch in the trunk floor.
    ronswanson likes this.

  7. #5
    doc538 is offline Cadillac Owners Member
    Automobile(s): 1994 Deville Concourse
    Join Date
    Oct 2013

    Re: How-to Cheap fix for Jumping Gas Gauge 98-04 Sevilles

    I am curious about the fact you are not replacing the rheostat portion of the sensor, just the arm which is nothing but a position connector to the rheostat. If this is the case then why not simply clean up the old arms connector ends with some very fine sand paper and save the cost of a new arm? It has been my experience on other cars that the wear is also on the rheostat surface.

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