This just happened.Working fine until the car was down for a month or so for some brake work.Now the guage registers EMPTY.God I don't want to drop the tank!!This is on an 82

 

I had the same proplem with one of our 77's . crawl under your car at the left rear. near the antenna. you will find a wireing conn. comeing off the top of the gas tank. unplug this two wire conn. insert a jumper wire accross the two wires heading back to the car. with these two wires hooked together you will have grounded you fuel gauge if all wireing is good. turn on your ign. your gauge should read over full. If it does not you propably have a bad ground. follow wire from conn. to frame behind tank. If your gauge does read over full wireing and gauge are working fine. Pull tank and sending unit.

 

I don't know how different the sending unit is on an '82 than an '80, but I pulled my sending unit through the gas door with no problems. Just have to be slow a patient.

 

Sometimes a few sharp jolts can get things like this going again ... try rattling the car over some rough RR tracks etc.

 

Don't need to drop the tank. Its either the float or the wiring. the yellow thing is the float.

 

This happens on all 82 vettes.
The float gets hung up on the blatter inside the tank.

The only thing you can do to is fill your tank all the way up and keep it full until the gauge frees itself and reads full.

Your gauge will now work from full to about half a tank, or until it gets caught on the blatter again.

~ Or buy a new gas tank, but brand new ones do not exist.

 

Mine is pegged past FULL.Should I replace the pump.I've got a NOS 84 pump still in the box and it reads for 84 Vette only.I'm guessing it's the same pump as my 82.Should I just go ahead and get an 85 pump.You are right tho',when I was able to get it working it would work until half tank and get stick again.I'd fill it up and do a couple of Nascar back and forth to get it working again.I'd hate to replace with an 85 unit just to have it work until half a tank.I keep my tank full because I know that pump life is extended by keeping enough fuel in it for lubrication.

 

I had this issue years ago. I would first check the wiring under the rubber boot of the filler neck. If that is ok it could be the plastic bladder inside the tank has collapsed slightly. This causes the fuel float not to rise. To remove the fuel pump and float assembly first remove the gas filler door. Then remove the rubber drain boot from the filler neck. Cover the back area of the car with a plastic cover. Cut a hole in the plastic around the filler hole and use duct tape to attach the plastic to the inside of the filler hole. The reason you do this is to protect the paint from gasoline that may spill onto the back spoiler area.
Remove the wires and hoses from the float assm. Remove the bolts that attach the assm. to the tank. You should be able to pull the assm upward and out with a slight turning motion. You can now test the unit out of the tank. Reconnect the wires and turn the key to the first position of the ignition. Do not start the car! Move the float slowly through its travel and watch the fuel gauge through the rear window. If the gauge in the car is now operating than it is probably the plastic bladder in the tank. To resolve this issue I simply shortened the distance between the end of the float and the point where it pivots. Between these two points there is a bend in the float arm. Bend it in this area slightly so that the float will clear the plastic bladder where it collapsed in the tank. To test this in the car before you put the unit back in the car get some fishing line and take the end through the filler hole and attach it to the float. Connect the wires and install two or three of the bolts to the tank. Turn the key on again and by pulling up and letting down the string watch the gas gauge once again through the rear window. If it is now working or you can feel the float getting hung up when pulling the string than you are in the right area. If non of this is working I would suggest getting a GM shop manual for the 82. This manual is expensive but is worth every penny. I hope this may be of some help. Let us know.
Good Luck
Steve