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Fuel gauge question...even after reading hundreds of search post.

Discussion in 'The Garage' started by jakeslim, Apr 30, 2003.

  1. jakeslim

    jakeslim 1/2 ton status

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    If my fuel tank is empty, and my fuel gauge is pointing to the half way mark, what is the problem?
    1--sender wire
    2--sender unit
    3--gauge
    4--ground for sender unit
    6--the float is not working properly?

    Someone please clarify this. I really read through many, many post via "the search" but am still unclear.
     
  2. jakeslim

    jakeslim 1/2 ton status

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    ttt....anyone? I know I can't be the only one with this problem. It's a 77 k5.
     
  3. Don

    Don 1/2 ton status

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    Fuel tank sending unit, is t.u. purchase a new one. /forums/images/graemlins/eek.gif
     
  4. chevyfumes

    chevyfumes Court jester

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    Watch for the muzzleflash!
    Check the ground, some others have had the same prob and that was it, mine does the same thing also.... /forums/images/graemlins/eek.gif /forums/images/graemlins/thumb.gif
     
  5. jakeslim

    jakeslim 1/2 ton status

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    well, i'll see if i can mess with the ground tomorrow(its supposed to rain in this damn state). It seems there would be a definite solution to a problem that plagues many of us.
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

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    No ground it should go overfull as I recall, so unbolting the ground and turning the key on should force the gauge to move.

    If the gauge actually moves until it hits the halfway point, it's either the gauge or the sender more than likely though. But it never (ever!) hurts to check/clean grounds.
     
  7. chevyfumes

    chevyfumes Court jester

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    Watch for the muzzleflash!
    [ QUOTE ]
    No ground it should go overfull as I recall

    [/ QUOTE ] Thats what I got outta his prob [ QUOTE ]
    If my fuel tank is empty, and my fuel gauge is pointing to the half way mark

    [/ QUOTE ] /forums/images/graemlins/eek.gifjust that it would be over what it actually said.... /forums/images/graemlins/1zhelp.gif
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Official GM "fuel gauge short test"

    Basically, it says disconnect the pink wire, and turn the key to "run". If it reads "full" then replace the gauge (allow 1 minute for the change in reading). If it still indicates empty check/repair pink wire for short to ground, cluster printed circuit, and gauge connections. Replace fuel gauge if pink wires, printed circuit, and gauge connections are good.

    Another test is to take the pink and ground it, then connect it to the ground wire. Both should send the gauge to "E". If fuel gage indicates correctly both times, repair/replace sender. If pink to ground test fails (doesn't read E), check pink wire, printed circuit, and gauge connections. If those are fine, replace gauge. If Pink to ground wire test fails, check/repair the black ground wire.

    The sender test is more complex, as the tester varies the resistance between 0 and 90 ohms which is empty and full, respectively. Basically, if that works the gage correctly, that means the sender is bad.

    You could do this yourself if you pull the sender from the tank (if you are pretty sure thats the problem after other testing). Measure resistance between the pink wire and the ground wire. Move the float arm from bottom to top (empty to full) Empty should be 0, full 90, and everything in between should be fairly close (IE approx halfway is 45, etc). Can't move the float very fast though, have to let it "settle" to get a good measurement.
     

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