IIA
09-16-2017, 11:40 PM
My fuel gauge has been acting funny - reading full when full but empty when there's still fuel in it. So, after checking the sender and the voltage stabilizer, I tested the gauge today. The results were off so I want to make sure my test was reliable before I order a new one. Does this sound right:
I removed the gauge and connected the terminal nearest the F side to the positive terminal of a reliable 10v power source. I connected the E terminal to one side of an adjustable resistor (to simulate the sender) and the other side of the resistor to the ground of the power source. I ran 10v through the gauge at various resistances from 0 to 260. I got those numbers from a chart in another post. Below are the results I got. All the numbers are rough. I estimated what I think the gauge reading should have been on the percentages in the chart and a 12gal tank.
Ohms
Gauge
Should Be
260
Below E
E
207
E
~1/4
135
~1/8
1/2
72
~3/8
3/4
42
~5/8
7/8
10
F+
F
0
F+
So, assuming my test setup was OK, the next question is whether the gauge can be fixed (it's a Smith - probably original).
I removed the gauge and connected the terminal nearest the F side to the positive terminal of a reliable 10v power source. I connected the E terminal to one side of an adjustable resistor (to simulate the sender) and the other side of the resistor to the ground of the power source. I ran 10v through the gauge at various resistances from 0 to 260. I got those numbers from a chart in another post. Below are the results I got. All the numbers are rough. I estimated what I think the gauge reading should have been on the percentages in the chart and a 12gal tank.
Ohms
Gauge
Should Be
260
Below E
E
207
E
~1/4
135
~1/8
1/2
72
~3/8
3/4
42
~5/8
7/8
10
F+
F
0
F+
So, assuming my test setup was OK, the next question is whether the gauge can be fixed (it's a Smith - probably original).