71 Vista Cruiser just got 3 months ago, I did not drive it much the first month as I was going though it . I knew the fuel gauge did not work, grounded the feed wire and the gauge went to E, so the gauge is good. After driving it some I noticed the gauge was not pointing at the O in hot it had moved between the H and the F. I put some fuel in did not fill up and it was pointing at the O again it has continued to be consistent , I fuel up when it points at F. I still use my wooden stick just to be safe. I will replace the sender unit this winter.

 

Sender wire and gauge are good. What you are describing is a bad sender.

 

Photo of the gauge?

I can't figure out why there's a "HOT" on a fuel gauge.

Did you ever test the ground side of the sender circuit?

 

The engine temp warning light is just to bottom right of the fuel gauge with the word hot, sorry for the misdirection , ground checked out good

 

With what? A new one? Good luck finding one. While new sending units are available for the non-wagon Cutlasses of that vintage, sending units for wagons are not made, at least not that I could ever find. You might find one on ebay, but the cost could be high.

 

This all could be nothing more than an intermittent ground. Your test of grounding the gauge side of the wire between the gauge and the sending unit is only a partial test. Presumably the gauge goes to F or well beyond it, as you're describing now with talk of which letter in HOT it's pointing at, when you REMOVE the wire from ground with the key on. Given that the needle STILL points to places beyond the F mark when the wiring is connected suggests that you have an intermittent open circuit. You need to check the OTHER wire coming off the sending unit that is grounded to the chassis and make sure that it is securely connected and that the connection is clean and not dirty or corroded.

In the end, the problem might still be a bad sending unit. But you want to rule out all of the other, easier-to-fix possibilities first as removing the fuel tank is no picnic, if you have to do that to get at the sending unit, and, as I've noted, finding a replacement sending unit won't be much of a walk in the park, either.

 

I did check and cleaned the ground all good, I know it is no picnic to r&r the tank, what is strange is the consistly of the gauge reading, I thought at first it was an intermittent fault also. For the sender replacement I have been told you can make a working unit by using parts from both a std and the wagon units by the guys at The Parts Place, I live only about 20 miles away from them.

 

The only way to know whats going on and how far gone the sender is, is to take it apart.

 

The one good thing about the VC tank location is it lends itself to stick check of the fuel level. I think removal of the tank will wait until I get the rear bumper recromed, no real need to put it out of service just for the sender troubles