'67 Fury III fuel gauge questions???

Early C Bodies - The Slab Side Years

  1. John Reddie

    John Reddie New Member

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    My '67 Fury's fuel gauge is acting up recently. I put about 10 gallons in it and the gauge went to almost 3/4 on the gauge. Next thing I knew (a few minutes later) it was reading just above empty then up to 1/2. Then next day it was not reading anything while driving, like it would when the switch was off. Then after a short while it was up to just a whisker over 1/4. I got underneath and cleaned up where the ground wire connects so that is secure and shiny. I removed the wire from the sender and checked for power with the switch on. My test light blinked on and off like a directional light would. Is this what should happen here?
    Before replacing the sender, I want to remove it and be sure that the float isn't messed up. Any tips or suggestions are truly welcome. Sorry for the long post but I want to fully explain what is occurring. Thanks again.
    John
     
  2. Davea Lux

    Davea Lux Old Man with a Hat FCBO Gold Member

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    The cluster voltage regulator will make the test light blink if it is working properly. I suspect that your sending unit float might be fuel logged. Remove the sending unit and check the float for fuel intrusion by shaking it. You need to have the tank as empty as you can get it before removing the sending unit. If the sending unit is badly rusted, the resistance wire in the assembly is probably corroded and that could also cause your erratic readings to the fuel gauge. Be sure to save you existing lock ring for the sending unit, the replacement ones that come with a new sending unit are a POS.

    Dave
     
  3. John Reddie

    John Reddie New Member

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    Thank you Dave. I will do what you suggest.
    John
     
  4. HWYCRZR

    HWYCRZR Senior Member FCBO Gold Member

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    Check the resistance at the sender with an ohmmeter
    unplug your wire from the sender. Clip the black ohmmeter wire to a ground and the red to your sending unit.
    Empty is around 74 ohms, half tank around 23 ohms and full tank around 10 ohms.
    If that looks about right Based on how much fuel you think you have then you can have someone bounce the car. If It is wildly erratic then it is likely your sending unit. If everything seems normal, plug the sender in and go up under your dash to the sending wire and see if you get the same result.
    I fought my original sending unit. Sitting still it read fine when I took off the fuel level dropped about 1/4 tank. It turns out my sender was a little twisted from a previous removal plus the wiper was worn out so every bump would get me a different reading.
     
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  5. John Reddie

    John Reddie New Member

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    Thank you for your response.
    John