Which is bad, Fuel gauge or resistor?

[leftybass209]

I thought my fuel gauge was functioning properly as I had about a quarter tank, and it read a quarter tank. After I filled it past 3/4 I noticed the fuel gauge still read 1/4 tank.

I verified the sender is correct, reading 1.5 ohms empty, and about 92 ohms full.

When I operate the sender by hand, the fuel gauge will go to empty with the float, but will only stop at 1/4 tank when the sender reaches roughly 20-23 ohms.

Wiring and grounds are all great!

I have the fault isolated to the gauge, or the resistor on the back of the gauge, but I'm uncertain how to check which it could be.

The gauge will read empty when the terminal is grounded, but only reads to about 1:30- 2 o'clock position with the wire unattached.

Any ideas where to go from here?

[leftybass209]

After finding some Ohm readings to compare the fuel gauges (I have two) I found that both my fuel gauges aren't even close to spec when measuring resistance from either left or right post to ground, with or without the resistor on the back of the gauge.

I ordered a new gauge, hoping that it will cure this issue. fingers crossed!

[TBONE1964]

Very common when the resistor goes bad. It will not allow the gauge needle to move past 1/4 tank.

When you take the resistor off, the ohm reading across the resistor should be somewhere around 100 ohms give or take a few.

If you have bought a new aftermarket gauge, it will have a built in resistor and there is no need for the external one.

If you need a resistor for your OE fuel gauge, send me your address on a PM and I will drop one in the mail for you.

Curious to see how this turns out.

Hope this helps,
Tom

[67-72lover]

[quote=leftybass209;7317138]After finding some Ohm readings to compare the fuel gauges (I have two) I found that both my fuel gauges aren't even close to spec when measuring resistance from either left or right post to ground, with or without the resistor on the back of the gauge.

I ordered a new gauge, hoping that it will cure this issue. fingers crossed! [/quote

..

[Duner97]

Originally Posted by TBONE1964

Very common when the resistor goes bad. It will not allow the gauge needle to move past 1/4 tank.

When you take the resistor off, the ohm reading across the resistor should be somewhere around 100 ohms give or take a few.

If you have bought a new aftermarket gauge, it will have a built in resistor and there is no need for the external one.

If you need a resistor for your OE fuel gauge, send me your address on a PM and I will drop one in the mail for you.

Curious to see how this turns out.

Hope this helps,
Tom

Reading through old posts after finding out my fuel gauge, which has never worked, is missing the resistor. Doesn’t seem as though those resistors are easy to come by online, could I get away with an old school, plain ol 100 ohm resistor?
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