Gas gauge problem

Discussion in 'Mazda Truck Forum' started by 1984K30, Mar 23, 2015.

  1. 1984K30

    1984K30 New Member

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    I have a 84 k30 with dual tanks I only use the drive side tank cause the other one leaks.
    My problem is when I get in my gauge is on full(with switch off) when I turn the switch on the gas turns past full like its work but it's not with in E and F so I'm not sure how much gas I have.
     
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  2. MrMarty51

    MrMarty51 Full Member

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    Welcome to the forum K30, good to have You aboard.

    It seems that My 79 K20 developed that problem just yesterday.
    I am not sure of the cause for this but, maybe someone else in the forum might know and, chime in.
    I am thinking that, I am going to remove the clusters covers and, twist the gauge back to the E and then, turn on the ignition switch and see whut happens.
    May or may not be a fix and, I definitely will be looking for the cause.
     
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  3. MrMarty51

    MrMarty51 Full Member

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    I got out the book.
    Try sanding and cleaning the ground connection at the tanks.
    There will be a wire coming from the sending unit to a bolt into the frame. Possibly loose, rusted or broken.
     
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  4. 1984K30

    1984K30 New Member

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    Let me no if that fixs it. I'm going to mess with mine this evening and was wondering if you found the cause. And thanks for the input
     
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  5. MrMarty51

    MrMarty51 Full Member

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    OK will most likely be next week before I can get toooit.
    Please post in what You find out with Yours.
     
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  6. 1984K30

    1984K30 New Member

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    All my wire look good. So idk what to do anyone got any advice ?
     
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  7. 1984K30

    1984K30 New Member

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    So all my grounds are good, do you think it could be my selector value ? I'm not sure how to fix it. I drop my passenger side tank and check it really good, and while I have it off I'll fix the hole. So does anyone no if the selector vaule can effect the fuel hand. If it does how do I check to see if it's working ?
     
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  8. gmctrucks

    gmctrucks Full Member

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    Do what Mr. Marty said sand and super clean the grounds they might look good but a dirty ground can drive one crazy also view some video's on You Tube.
     
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  9. MrMarty51

    MrMarty51 Full Member

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    Those grounding bolts are a boooger to get to. If You are going to drop the tank, remove the valve then, check the electrical circuits with a volt~ohmmeter.
    With the valve removed, switch tanks, Should be able to touch the ohm meter to one of the tanks sender connectors, then, to the body of the valve, should read close to 0.000 on one, switch to the other tank and change the meters lead to that tanks connector, should read about the same. If this is of the old solenoid valve. The solenoid valve has a spring to drive the valve to one tank and then, it needs a constant 12V. supply to keep the solenoid held over for the other tank.

    The motor driven valve could be a bit more tricky, use a jumper wire for the 12 volt source and another jumper wire to ground, try the ohm meter on one of the sender connectors, if no reading, try the other one, should be same as above 0.00 or so. then, use the jumper wire and the grounding wire and, touch the hot lead to one of the tank switching connectors, hold it there for about 30 seconds then, try the other tank sender connectors for an ohms reading. The "Motor Driven Valve" is different from the solenoid valve, a little bigger and a couple of more wires. It takes about 30 seconds of continuous voltage to the selector connector for the motor to drive the valve across to the other tank then, whjen doing the switching from inside the cab, the dash switch returns to a neutral position, no voltage going to the valve.
     
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  10. chevychase

    chevychase Semi-Admin
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    If pegging full either a bad ground..or gauge is bad.
     

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