He said the voltage is fluctuating at the wire. You would think if grounded there would be no signal.
It fluctuates because the voltage limiter cycles on and off. The gauges have a bunch of averaging in their design.
Thats why I daid if the wire between the gauge and the tank was grounded the poster would not have the voltage fluctuation. If it was grounded he would have no voltage at the tank sender plug. I agree with the voltage fluctuation the limiter is working. Quick Ohm test like I suggested will tell him something.
Yes you're right. I was thinking he was checking at the gauge
I agree.
If the wire was pinched he would not be seeing fluctuating voltage at the plug on the sending unit. If that wire was pinched to ground it would kill the signal. If he ohm's the sending unit that will give him an idea. On the other hand if he did not have fluctuating voltage at the senders plug I would agree that the pinched wire to ground was causing the gauge to peg.
It is an aftermarket sending unit.
The things Pnora are telling you are accurate, and good advice. If everything he says checks out, then I wouldnt be too surprised to find that the sender is shorting internally (ohm readings are inconsistent, or inaccurate).
Then with the wire unplugged Ohm the sender and tell us what it reads.
It should be easy enough to check. If there is power to the sending unit then a test light will light if you connect one end of the test light to ground and you put the probe into the wire socket at the tank making sure to disconnect the sending wire first. After that hook one end of the light to power and probe the sending unit socket again. If the wire is seeing ground the test light should light up. I’ll also check the wiring diagram in the service manual later to see if I can verify this. Too bad that this issue didn’t come up a few weeks ago when I was having issues with my gas gauge. My problem was that the gauge wasn’t working at all. Turns out the float was full of fuel. Luckily I had a new float from National Parts Depot from a Ford Mustang that’s a little shorter but was made out of thicker brass and that fixed the issue for me. FYI, I still haven’t found the leak in the old float although there’s still gas trapped inside. I’ve even heated the float and it still didn’t leak.
The voltage limiter is the original thats all I know
The reading I get is 66.4 the sender is in the tank The tank is almost full.
