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Fuel gauge issues

Discussion in 'CJ' started by Rotorhead, Feb 21, 2020.

  1. Feb 21, 2020 at 7:38 PM
    #1
    Rotorhead

    #1
    Rotorhead [OP] New Member

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    First Name:
    Jeff
    Vehicle:
    1983 cj7
    Painless performance wiring harness
    I’m having fuel gauge issues on my 83 CJ7. Have just finished rewire with a painless performance wiring harness. Everything is connected/wired correctly according to both the painless wiring instructions and the diagrams shown in the chilton manual. Tank is 15 gallons and has around 2 gallons in it and gauge reads just over full. This is the second gauge to do this and sending unit is new as well. Gauge will read off the charts full when float is in full position. Anyone have any ideas on what could be the issue here?
     
    Rotorhead, Feb 21, 2020
    #1
  2. Feb 22, 2020 at 6:22 AM
    #2
    kowdog

    #2
    kowdog Member

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    Steven
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    89 YJ
    Converting to 91 4.0L 5-spd. Bought a wrecked 91 Saraha 65k miles.
    clean the grounds on both, and check the connector on the tank. Most likely a bad ground, check doe a good tight clean connection on the grounding lug.
     
    kowdog, Feb 22, 2020
    #2
  3. Feb 22, 2020 at 3:38 PM
    #3
    Jim Beam

    #3
    Jim Beam Well-Known Member

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    1986 CJ7
    Fuel Injection, Dana 44s, T18, 4.10s w/lockers
    A good place to ground the fuel tank sending unit ground wire is to the battery negative post, normally it is grounded to the frame. I remember many years back there used to be a guy on one of the forums named John Strenk who was pretty much a Jeep CJ guru. I found some info here that might help: https://www.bing.com/search?q=john+...s=n&sk=&cvid=d212d4ecdb8845098108561864cd8272. Although, you might have fried the gauge.
     
    Jim Beam, Feb 22, 2020
    #3
  4. Feb 23, 2020 at 8:02 AM
    #4
    kowdog

    #4
    kowdog Member

    Joined:
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    Gender:
    Male
    First Name:
    Steven
    Vehicle:
    89 YJ
    Converting to 91 4.0L 5-spd. Bought a wrecked 91 Saraha 65k miles.
    I had an issue with the ground located on the fuel pump housing. The ground lug was loose where it clipped to the housing near the pump inlet/strainer. I replaced the connector, no issues since. I agree with JB, suspect the gage at this point as well. Look on u-tube for videos relating to testing the gage, it is rather easy to do. On the float, the readings will change with the movement of the float, put your multimeter in omms, one lead to ground, the other to the hot wire on the float. If the reading changes with the movement, it's ok. The gage reads somewhat the same way. Have fun, enjoy the journey..... that's why you got the jeep, right??
     
    kowdog, Feb 23, 2020
    #4
  5. Feb 23, 2020 at 4:44 PM
    #5
    Jim Beam

    #5
    Jim Beam Well-Known Member

    Joined:
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    Member:
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    Messages:
    596
    Gender:
    Male
    First Name:
    Donald
    Vehicle:
    1986 CJ7
    Fuel Injection, Dana 44s, T18, 4.10s w/lockers
    I have seen a few articles where a small door is installed in the CJ or YJ bed for easy access to the sending unit. For a more accurate reading there is a screwdriver adjustment on the back of the CJ gauge, I am not sure about adjusting the later model Jeeps though.
     
    Jim Beam, Feb 23, 2020
    #5
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