Fuel Guage doesn't go below half

Discussion in 'General Chevy & GM Tech Questions' started by jfr1800, Apr 9, 2011.

  1. jfr1800

    jfr1800 New Member

    A friend has a 2007 Chevy 1500 classic and the fuel guage will not read below half tank. We have changed the sending unit, the problem still exists. We sawpped the cluster to see if it was the guage iteself, but the problem is still there. We also swapped out PCM's and the problem still there. The sending unit is giving the PCM a reading of 160 ohms which is a 1/4 tank and by looking in the tank that is about what is in the tank.

    Any thoughts on where to go from here?

  2. SkullMountainRider

    SkullMountainRider New Member

    Did you inspect the float for the tank. It seems that it's sticking at 1/2 tank and won't go any lower. It's the only thing I could see causing that..
  3. jfr1800

    jfr1800 New Member

    Fuel guage will not read less than half tank

    Thanks but we checked the float when we had it out and currently the tank is 1/4 full and the reading to the PCM is 160 ohms which should corespond to 1/4 tank but the guage still reads 1/2 tank. Sawped clusters with another truck but still the guage read half tank.

  4. SkullMountainRider

    SkullMountainRider New Member

    Puzzling is right. The fuel gauge hasn't worked at all in my 87 S10 since I bought it in the late 90's, I just try to keep a full tank in it. At least your friend has an idea of what's in the tank. Better than not knowing at all.
  5. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    The actual gauge in the cluster may not be working then, those can be tested at the dealership
  6. jfr1800

    jfr1800 New Member

    Well we got the problem fixed. Even though the current readings from the sending unit seemed to be what they should be we repalced the complete fuel pump sending unit with one from another truck and the guage worked when we moved the float up and down. After putting the unit from the other truck in the tank and bolting the box back on went to fill the tank but the guage now would not show full, so pulled the box off again and took out the unit from the tank and compaired it to the old one and we noticed that the lenght of the arms on the float were different. Probily because the tanks were different capacity. Swaping the arms on the unit cured the problem. All is right with the world.

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