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Mystery of fuel gauge / sender

Discussion in 'The Garage' started by DieselDan, Oct 18, 2003.

  1. DieselDan

    DieselDan 1/2 ton status

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    OK, this is really starting to baffle me. My DD jimmy was parked for a week. I come back and is reading almost empty. Fast forward a month later and I'm finally getting time to fix this (ran out once due to guesstmation of fuel level /forums/images/graemlins/blush.gif )

    I can get my hand to connections, pulled the hot (pink) lead. Fuel gauge to max full. Alright, gauge still works. So last night I pulled the tank (PITA doing this w/o an extra pair of hands)("jeez, I thought this was almost empty!"). Take the sender out - looks OK. Connect the sender back up (out of the tank), move the sender up & down - nothing. Open up the inside, clean out alittle crud. Assembly sender, bench test it with multimeter - IT WORKS. Put everything back together, wrestle tank back between rails. Turn key on - gauge still reads empty /forums/images/graemlins/angryfire.gif

    WTF am I missing? I cleaned the connections up. Somehow I'm shorting (little to no resistance) when I connect up the sender. Fricken senders are expensive, this ones about a year old /forums/images/graemlins/mad.gif
     
  2. Confedneck

    Confedneck 3/4 ton status

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    you sure the float arm isnt broken or bent?...maybe you have a pinched or chafed wire in that harness between the tank and gauge..
     
  3. DieselDan

    DieselDan 1/2 ton status

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    Nope, float arm looked fine. Had the sender apart, not much to it. I'll be checking again for a bad wire, but if the wire was shorting-out it should read EMPTY even when disconnected, right? /forums/images/graemlins/thinking.gif
     
  4. mojo-jojo

    mojo-jojo 1/2 ton status

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    I think it might be a bad ground. If I'm not mistaken bad ground= empty, bad positive= full
     
  5. Ryan B.

    Ryan B. 3/4 ton status GMOTM Winner

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    When you bench tested the sending unit and it came out okay...
    You should've grabbed that brown wire going to it: with the key on, ground it, the gauge should read empty, open the circuit and it should read full... that will test the gauge and the wiring to the sending unit.
    I'll bet that brown wire is grounded out on the frame somewhere, maybe near the exhaust.

    /forums/images/graemlins/grin.gif
     
  6. DieselDan

    DieselDan 1/2 ton status

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    My hot wire is pink. I didn't try grounding it against the frame, but when I disonnected it my gauge did go FULL.

    I can get my hand to connections, pulled the hot (pink) lead. Fuel gauge to max full. Alright, gauge still works.

    I'll be checking the wires again tomorrow. But if I shorting out, why would it go to FULL when I disconnect from the sender. It would be still shorted, right? /forums/images/graemlins/rolleyes.gif
     

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