Fuel gauge still only shows FULL

[69dodge383]

Gas gauge ALWAYS goes to full and stays there...even if I ground the tank to the chassis, body or anything on the car. I have used a small wire with alligator clips, same result. I even tried the negative side of a set of battery cables. Still shows full. At one time or another about a year and a half ago my brother in law came over to help me and grounded the tank while I was in the car and the gauge started to come in line and read properly. No matter what I have done since then it seems I cannot get it to ground and read properly.

Any ideas to get this to work?

Doug

[tan top]

 pull the blue wire off the fuel tank sender unit  , & see if the gauge still reads full

[69dodge383]

Just went out. Grounded tank. Put key on. Gauge went to all the way full.

Pulled wire from sending unit, gauge went all the way past empty slowly, but went past empty.

Doug

[histoy]

Sounds like you have a bad sending unit in the tank.

[69dodge383]

Sending unit was new when installed. Whats the chance it has gone bad? 

How would it have gone bad?

Thanks

Doug

[John_Kunkel]

Use a multimeter to check the resistance between the sender terminal and the sender body, if it's near zero when the tank isn't full the sender is bad (grounded internally).