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Fuel gauge

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by AZK5, Mar 16, 2000.

  1. AZK5

    AZK5 1/2 ton status

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    I have a 73 K5 and the fuel gauge reads way past full no matter what the gas level is. Has anyone ever had this problem and found the cure?
    CB
     
  2. delta9blazer

    delta9blazer 1/2 ton status

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    there was a thread along this line a little while ago.
    if i remember correctly, the gauge receives an electrical signal from the sending unit. if you show way past full, its either disconnected, or shorting.

    <font color=purple>delta9blazer</font color=purple>
     
  3. Boss

    Boss 1/2 ton status Author

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    Dude,

    I got the same problem with my 75'. The thing reads way past full and then when I'm driving its going crazy on me going left and right. But I do notice that when I put it in nuetral, it will tell me exactly where it is. Wierd.
    Boss
     
  4. delta9blazer

    delta9blazer 1/2 ton status

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    got a short in your steering column?
    maybe the wires to your gauge are getting pinched. does it read true in neutral if you turn the wheel back and forth?

    <font color=purple>delta9blazer</font color=purple>
     
  5. Boss

    Boss 1/2 ton status Author

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    Delta9,
    I don't think so, but I'm not sure b/c I didn't pay too much attention. But I think it reads true when I just put it in neutral, I don't think I turn the wheel. I'll check after work.
    Boss
     
  6. Blazer79

    Blazer79 1/2 ton status

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    My Blazer used to read past full all the time. Got underneath and found the sending unit cable cut. Problem solved.

    <font color=purple>////////
    Drive it like gas is </font color=purple><font color=red>$2.00/gal!!!</font color=red>
    [​IMG]
     
  7. **b**

    **b** 1/2 ton status

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    Dont even get me started
    with those dam Sending units!
     
  8. Waxer

    Waxer 1/2 ton status Author

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    Mine used to read past full all the time when I first bought her. I had to replace the fuel tank and sender cause they were toast anyways and that fixed the problem.
     
  9. Steve88

    Steve88 1/2 ton status

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    we all know it isn't from the tank being full!...damn gas prices....! [​IMG]

    <font color=red>Steve88</font color=red>[​IMG]
    88K5 Silverado
    thunderdog@metallica.com
     
  10. **b**

    **b** 1/2 ton status

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    wax...
    yeah, the baffle in tank became
    loose and wiped out the sender...
    needle went to the right... right?
     
  11. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    It could be the gauge itself, too. I had to replace the gauge in an 83 Chev 1/2 ton that used to read inaccurately. Might be worth checking before you start pulling your gas tank......
     
  12. AZK5

    AZK5 1/2 ton status

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    I tried replacing the gauge first because a friend of mine was parting out a 1976 K5. The new gauge read exaclty the same spot as the old. It reads about 20 degrees past the full mark all the time. I've checked the connection at the tank and followed the wire back to the firewall, but haven't checked the wire under the dash.
    CB
     
  13. Goose

    Goose 1/2 ton status

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    AZK5:
    You will have a tan wire that connects your gage to your fuel sending unit. There will also be a black ground wire coming from the sending unit to a ground. Your gage is basically a ohmeter. The higher the fuel level, the higher the resistance and the higher the fuel gage reads. For the gage to work, the circuit has to be complete, or it reads max resistance(full tank). Make sure the black wire coming from the tank is grounded, check all the connections of the tan wire. It will go into the firewall junction box, the out of the fuse box directly to the connection on the back of your gage cluster. First check all the connections that complete the circuit. Are all the other gages working correctly? The gage cluster is grounded with a black wire as well. If it's loose some other gages may be acting weird or your dash lights may be dim. If all connections are good, it has to be either the sending unit or the gage itself. The wire should run up the passenger side frame rail and passsing close to the passenger engine mount where it enters the wiring group at the same place as your stater wires. Good luck

    the Goose
     
  14. Boss

    Boss 1/2 ton status Author

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    Delta9,

    Just to let you know about the fuel guage reading correct while in neutral. No, I don't have to move the steering wheel around. I moved it and the fuel level stayed the same.
    Boss
     
  15. Waxer

    Waxer 1/2 ton status Author

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    Yes it used to be all the way to the right (Past Full).
    Sometimes which are very rare, it will do it. Read past full when there isnt a full tank. Guess I maybe have a short or ground working its way there.
     

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