1960 Buick fuel gauge

[60 Buick]

Hi there I have just acquired a 60 Invicta, the fuel gauge  sits at full  all of the time, I found the sender wire needed tightened then the gauge came down to 3/4 full but next time I  started back at full again, Does it need a earth wire from tank to chassis ? Thanks for your help , just an idea maybe my float is full and only came down to 3/4 after I dropped the tank abit to reach wire gauge is always at full

Edited April 23, 2021 by 60 Buick (see edit history)

[Bloo]

1 hour ago, 60 Buick said:

Does it need a earth wire from tank to chassis ?

 

Every old car with an electric gas gauge needs that but very few got it from the factory. The GM system is extremely sensitive to this because "Empty" on the gauge results when you have 0 ohms from the gauge wire to earth. If there are screws holding the sender into the tank, that is the best place to connect the earth wire from the chassis.

 

If you disconnect the gauge wire from the sender, the gauge should peg because it needs at least 30 ohms to make "Full" and a disconnected wire is nearly infinity. If you short the sender wire to earth, the gauge should go to "Empty". If it will do both those things, the wiring and the gauge are likely fine. Try a nice clean earthing point on the chassis to make the test, so you don't get fooled. If the gauge and wiring pass the test, and the earthing wire doesn't help. the problem is most likely with the sender in the tank.

 

 

Edited April 23, 2021 by Bloo (see edit history)