Fuel Gauge
Home Up


August 2016

After repairing the fuel pump bulkhead connector and putting everything back together, the car ran great again but the fuel gauge wasn't reading correctly.

I read that the sending unit was a 0 to 90 ohm rheostat (variable resistor). So I cobbled together a string of four 22 ohm resistors for a total of 88 Ohms. This was close enough to 90 Ohms to let me simulate the sending unit.

With this string of resistors I could test for:

Empty Tank (0 Ohms)
1/4 Tank (22 Ohms)
1/2 Tank (44 Ohms)
3/4 Tank (66 Ohms)
Full Tank (88 Ohms)

The fuel gauge indicated all five fuel levels. So, this proved that the fuel gauge was working. That's when I realized that I didn't have a proper ground. Once I found a good ground for the sending unit, the fuel gauge began working again.