Fuel Gauge Question 89 Comp

[jwelniak]

I have an 89 Comp with a 351. One day this past summer the fuel gauge went all the way to the empty side and has not moved since. What are the possible causes of this? I'm sure that we will check the wiring first but what other things could cause this problem? Any info is appreciated. Thanks.

[OUI]

It's one of four things: 1) The sending unit is bad; 2) The guage is bad; 3) The wires going to the guage are bad; 4) No power going to the sending unit.

The gauge is a volt meter. Power goes into the sending unit and the power is read at the fuel guage. The sending unit is a variable resister which increase power as the float rises in the tank. So, check to make sure there is power going to the sending unit. If there is, then jump the power to the wire going to the guage -- if the guage goes to full then the sending unit is bad, if not then the gauge is bad or the wire going to the gauge is bad. Also make sure you have a good ground going to the tank.