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  1. #1
    Join Date
    May 2002
    Location
    SAN ANTONIO TX
    Posts
    176

    Default Gas gage reads full all the time

    Recently the gas gage on my gsx has started reading full all the time. I have tried disconnecting the wire that goes to the sending unit and no change. I'm guessing that this is a common problem. What do I need to do to solve the problem? Thanks for your help.
    Randy
    70 QQ STAGE 1 GSX
    71 GS455 CONV. (RED) W/BUCKET SEATS & CONSOLE
    EX: 70 1010 STAGE 1 GSX
    EX: 72 GS455 CONV. (WHITE)
    EX: 72 GS350 CONV. (SILVER)
    EX: 70 SS396 CHEVELLE (GOLD)

  2. #2
    Join Date
    Mar 2002
    Location
    St Louis
    Posts
    10,388

    Default Re: Gas gage reads full all the time

    Randy the gas guage can be checked if you unhook it at the sending unit and ground the wire it should go up. Since its up all the time I would look for a bad wire . I have personally never seen a bad guage on one of these. Has anyone had the guage panel out? There are a few grounds on it. cig lighter area and between each guage. I thnk theres another by the ww switch
    John & Terry Kemper
    GSCA #4322
    BPG #1373
    72 Stage 1 Suncoupe
    72 Stage 1 Suncoupe clone
    70 Sportwagon

  3. #3
    Join Date
    Jul 2003
    Location
    Edinboro, Pa
    Posts
    1,226

    Default Re: Gas gage reads full all the time

    Turn the key on and with a test light probe the wire you disconnected back there at the trunk and see if you have voltage coming back. If you do, have someone read the gas gauge. The test light should make it read around 1/4 of a tank, depending on the test light. If this is the case ( likely ) replace the tank sending unit.

  4. #4
    Join Date
    Aug 2004
    Posts
    2,039

    Exclamation Re: Gas gage reads full all the time

    The easy check is the ground wire from the unit to the body, or there is corrosion on the connector in the trunk.

    There is a great troubleshooting tree in the service manual. Do you have it?

  5. #5
    Join Date
    Apr 2006
    Posts
    1,306

    Default Re: Gas gage reads full all the time

    Man, I wish my gas gauge read full all the time! I have to PAY for it to read full!

  6. #6
    Join Date
    Feb 2002
    Location
    Grand Haven MI
    Posts
    1,459

    Default Re: Gas gage reads full all the time

    Quote Originally Posted by PaulGS View Post
    The easy check is the ground wire from the unit to the body, or there is corrosion on the connector in the trunk.

    There is a great troubleshooting tree in the service manual. Do you have it?

    Paul is right - bad ground will make the gage read above full.

    Check the wire under the back bumper. Worst case is if the wire is broken above the tank and you have to drop it. Probably a corroded connection to the frame crossmember behind the bumper.
    John Eberly
    '68 GS400
    former '71 Centurion Convertible (gave to my brother)
    former '95 Riviera (gave to my daughter)
    WAITAMINNIT!!! I'M RUNNING OUT OF CARS!!!
    BPG #1430

  7. #7
    Join Date
    Apr 2004
    Location
    Salt Lake City, Utah
    Posts
    1,195

    Default Re: Gas gage reads full all the time

    My grandpa (previous owner of my Skylark) once had a problem with the gauge reading either always full or always empty, I forget which. He took it into a shop, and they found out that the float mechanism inside the tank had managed to flip itself upside down or something like that, causing weird readings.

    Keep in my mind that my grandpa is old, and says lots of things ... worth a thought though.
    ~Mike
    '66 Skylark 340-4
    '71 Electra 225 455-4

  8. #8
    Join Date
    Feb 2002
    Location
    Dearborn Mi
    Posts
    1,407

    Default Re: Gas gage reads full all the time

    My 71 does the same thing. I have checked everything that I can get to. I now have to drop the tank and see whats going on at the sending unit.
    71 GS 350 Convertible 4 speed
    70 GS 455
    69 GS Stage 2 10.08@131
    68/69 Stepchild Nation

  9. #9
    Join Date
    Mar 2003
    Location
    Westerville, OH
    Posts
    1,714

    Default Re: Gas gage reads full all the time

    I don't want to hack into this thread but I had a similar problem last year which ended up being a bad sender. I replaced the sender, and now I have the opposite problem. My needle points to empty. Sometimes, if I take off fast, my needle will point to the appropriate area for a few days and then it will fall back to empty.

    -mark
    Mark "Sharky" Stover
    73 Century Regal 455/400
    01 Dodge Ram 1500
    BPG #1880

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  10. #10
    Join Date
    Dec 2005
    Location
    Aston, Pennsylvania
    Posts
    714

    Default Re: Gas gage reads full all the time

    I've got the same problem with the gas gauge, where's the connector at in the trunk?
    Nick

    1968 GS400 auto- The green paint reminds me of where all my money went.
    1972 Olds Cutlass Supreme rag top, 350, 4 speed- Dad's ride.
    2000 S10 4 banger- underpowered workhorse

    Horsepower is how fast you go into the wall, torque is how much of the wall you take with you.

  11. #11
    Join Date
    Feb 2002
    Location
    Louisville,Kentucky 40229
    Posts
    3,848

    Default Re: Gas gage reads full all the time

    Quote Originally Posted by BigBlock68 View Post
    I've got the same problem with the gas gauge, where's the connector at in the trunk?
    The wire travels with the wiring bundle that travels to the rear with all the tail light wires. When the bundle gets to the trunk it brakes off to a single wire and goes through the rear of the trunk (on driver's side) in a rubber gromet.

    On a 1970-72, it is a single tan colored wire. I would think it is also single on the eariler years also.

    It has a multi connection at the sterring colum, single connection in the trunk, a single connection on top of the sending unit.
    Michael Evans

    "Universal means the part universally does not fit anything until you make it"

    GSCA #1258

    Building the 1972 Skylark Suncoupe with a 464 , 400 Turbo 3.90's in a 12 bolt, 4-wheel disk brakes

    1.51 60-foot 7.14 ET (1/8 mile)

    Dyno run Before the Procharger when it broke the drive shaft (and other things)..........
    http://www.youtube.com/watch?v=nJhHk...eature=related

  12. #12
    Join Date
    Dec 2005
    Location
    Aston, Pennsylvania
    Posts
    714

    Default Re: Gas gage reads full all the time

    Thanks Michael.
    Nick

    1968 GS400 auto- The green paint reminds me of where all my money went.
    1972 Olds Cutlass Supreme rag top, 350, 4 speed- Dad's ride.
    2000 S10 4 banger- underpowered workhorse

    Horsepower is how fast you go into the wall, torque is how much of the wall you take with you.

 

 

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