[mainones]

I have a 1973 Plymouth Duster with a 225 slant six. I am having a problem with the fuel gauge. Sometimes it registers and sometimes it doesn't. I tap on the gauge and no change. Car has 98000 miles on it. What are the possibilities is is the sending unit in the tank. What is the best way to test the circuit? I have taken the wire off the sending unit and cleaned it with no change. Any ideas??

 

[dana44]

If it is a work/don't work, check the wiring first. There is a single wire to the tank, the body of the gauge is the ground. If you can have someone look at the gauge and you take the one wire and make a ground from the tank to the wire and the gauge pegs, rules out wiring, only if the gauge isn't shoing it is working to begin with. Basically it will check the working of the gauge itself.

 

[valiant67]

I agree with Dana. if the tank loses ground, the gauge doesn't work. I've had to run a new jumper wire to reground the tank to fix gas gauge issues a couple times.

 

[mainones]

So I finally checked the gauge. When I ground the single wire to the tank the gauge pegs. So my questions are. Does this mean the ground wire to ground the connection is doing its job? ( I had to fix it it was broken ) Does this mean all the wiring is OK? When I turn the ignition to run the gauge moves a little but not much. Is this the sign of a bad sending unit? Sorry with so many questions but I would like to make sure before I drop the tank to replace the sending unit. Also do I need to buy the tool to take out the sending unit or it there a different way I could take it out with common tools. Thanks!

 

[68RT]

Since you stated that it sometimes works, you may have an intermittant grounding of the tank which worked when you tested it. when driving you might lose that ground. Also, you might have an intermittant connection between the gauge and the tank or the sender might be intermittant. Problems that are intermittant are always a hard cure. I would take a wire and go from the sender mounting screw to a good body connection and try it for a while. If that does not work, then try to follow the wire back from the tank to the dash to make sure there are no loose/poor connections and if none found, try a new sender.