My fuel gauge is not very accurate. It is the original gauge from 65. I've checked the wiring and connectors. All seem pretty good. I'm thinking it might be the sender but if it is the gauge that is just not working correctly i might have to replace it. Anyway, does anyone know what the OHM rating should read on the gauge? I want to test it but I don't know if it is 0 OHM to 90 OHM (empty vs full tank).

 

I would check your connections with a multi meter. Find a source of power and clip the positive lead onto it. Touch the ground lead to the ground screw for the sender on the back of the cab. Note this voltage.

Now touch the lead to the sender itself. The voltage should be EXACTLY the same as the previous reading. If not, you have a bad connection.

Now check the voltage at the signal terminal on the sender and note this voltage. Then check the voltage at the signal wire on the back of the gauge. Again, the voltages should be EXACTLY the same.

If this all checks out well, let us know and I can dig up a thread on ow to "tune" your gauge to your sender.

 

I don't think the gauge has any such specification since it's responding to voltage changes. At least I couldn't find that in any of my books. So I checked a working sender it was 73 Ohms empty and 13 ohms full. I did find the ohm readings for a 1971 Mustang sender in one of the books and Ford says it should be 8-12 ohms full and 60-86 empty. One thing I did notice when I was checking gauges is the constant voltage regulator makes a difference in the reading on the gauge. I had three regulators and all checked good but all three gave a slightly different reading on the same gauge. You are probably going to have to pull the sender.

 

Thanks guys. I'll get the multi-meter out and see what I can find.

 

Typical range should be around 73 ohms to 10 ohms (73 ohms empty, 10 ohms full).