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Thread: Fuel gauge reading backwards after tank/ pump swap

  1. #1
    Tuner in Training
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    Fuel gauge reading backwards after tank/ pump swap

    I swapped my 2001 gmc fuel tank for a 05+ tank for the larger fuel bucket to run my dual pumps. my issue is my fuel gauge is reading backwards now and i cant figure out what to switch in my tune for it to read properly? i looked at a tune for a 05+ truck but i cant see whats different. any help is great thank you!

  2. #2
    Tuning Addict blindsquirrel's Avatar
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    Swap the two sender wires at the pump module. The '01 gauge is expecting to see 250 ohms full/40 ohms empty, '05 reads 40 ohms full/250 ohms empty. This is not something you can 'fix' in the tune.

  3. #3
    Tuning Addict blindsquirrel's Avatar
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    Wait, no... that won't work. Stupid me. It'll still be the same ohms with the float in the same position.

    If you could mount the sender card upside down, that would work. Well, it would give you the right electrical output.

  4. #4
    At least the gauge is accurate at 1/2 a tank.

  5. #5
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    my buddy told me to flip the markings on the actual gauge lol

  6. #6
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    Quote Originally Posted by blindsquirrel View Post
    Wait, no... that won't work. Stupid me. It'll still be the same ohms with the float in the same position.

    If you could mount the sender card upside down, that would work. Well, it would give you the right electrical output.
    im just going what the guys on the truck forum do when they swap the tanks, they say it can be changed in the tune so idk lol.

  7. #7
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    So i was able to fix it in the tune. i went under "Primary Volume" under the Fuel system tab and basically flipped the values.
    05+ sending unit values.PNG
    Pre 05 sending unit values.PNG