Re: Fuel Gauge Woes....

Posted by BigKev On 2010/3/26 16:13:15

If you have an electric fuel gauge then it works pretty simply. The sender on the top of the tank contains a variable resistor coil attached to a float arm. Power is applied to the dash gauge, and the ground wire from the gauge is attached to the sender back at the tank. The ground path travel through that variable resistor and then grounds at the tank body. So basically as the float in the tank moves, it changes the resistance to ground, and that make the needle move on the Fuel gauge.

The most common cause of a gauge not reading correctly or at all is either a bad ground at the tank, or a corroded connection on the wire between the gauge and the sender. Also if the wire gets shorted to ground this can cause the tank to read always empty or full. So clean and retighten all the electrical connections.

The other possibility is that the float in the tank has developed a pin-hole, and the float is full of gas, and has sunk to the bottom of the tank.

If all of those check out then you would have to check the sender to make sure the variable resistor is still in the correct range. If that checks out then the dash gauge is probably bad.