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Gas guage fluctuates

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by rockosangel, Oct 22, 2000.

  1. rockosangel

    rockosangel 1/2 ton status

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    Location:
    Round Rock, TX
    Does anyone know what would cause the gas gauge needle to fluctuate back and forth?
    I filled up the tank and the gauge works, it just fluctuated (spelling?) between full and 3/4 when I drove 150 miles round trip yesterday..
    It fluctuates all the time.. plus I hear a clicking noise under the dash when it fluctuates.. Kinda like the turn signal clicker.. any ideas ?
    Thanks in advance.. Rocko

    http://www.rockosangel.coloradok5.com
    http://www.rocko.coloradok5.com
     
  2. riz

    riz 3/4 ton status

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    <font color=purple>My gas gauge is a P.O.S. too..several people on here said it was their sending unit in the tank. Also, you might want to check all of your leads. Let me know if you find out anything else.</font color=purple>

    <font color=purple>L8r,

    .Riz.<font color=purple>
     
  3. Smitty

    Smitty 1/2 ton status

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    If you're hearing a clicking from the instrument cluster at the same time as the needle movement I'd be looking for a bad connection in that area.

    Smitty
     
  4. 90K5

    90K5 1/2 ton status

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    My gas gauge is a POS too! It goes fuller when I go uphill and start from a stoplight and goes lower as I slow down or go downhill. It also goes about an inch past full when its full and I can go a while on empty.

    90K5
     
  5. SilverSolder

    SilverSolder Registered Member

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    The needle on our '82 does the exact same thing (no clicking from under the dash though). The needle is only stable when the tank is completely full. I haven't dug into it yet. Too many other things to attend to. I did pick up a sending unit from a junk yard to try to understand how this might happen. Unless there is some sort of baffle around the sending unit in the tank, I can imagine how gas sloshing around in the tank might cause the float to bobble. One way to smooth the signal would be if a filter were in the circuit. I've looked at the electrical wiring diagram but didn't find any sort of filter. If you get to the bottom of this, I'd appreciate it if you would let me know.

    SilverSolder
     
  6. Goose

    Goose 1/2 ton status

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    Mine started doing this a while back. The gage is still accurate, but just bounces all over the place. It doesn't do it when all the way full or sitting still. I think there were some curcuits on the back of the fuel gage. One of the components is a restrictor of some sort that evens out the signals from the tank. This went bad so the signals from the fuel sloshing around don't get evened out. That's my theory anyway.

    Cruisin in my '73.
     

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