I have an 89 Jimmy 4x4 that has a faulty fuel gauge. It always reads empty regardless of how much gas is in the tank. I have been trying to resolve this issue for some time now and have at this point replaced the sending unit, fuel pump, and gas tank. I have also checked and cleaned every ground wire on the sending unit as well as the grounds from the battery to the engine and frame. After all this, the gauge still only reads empty. Here is the odd part, when I had the tank out and the sending unit connected outside of the tank, when I manually move the float arm assembly up and down the gauge works perfectly. I have done this twice now and everytime I put the sending unit back in the tank, the gauge does not work. Any suggestions of help with this will be much appreciated!!!

 

i wonder if its possible that its the wrong sending unit or its going in wrong somehow. if you said it works out of the tank then that means obviously your grounds, signal wire and gauge works its just getting hung up in the tank for some reason

but if i remember with these trucks you really cant put the sending unit in facing another way as it has a notch to line it up

 

you are correct it can only go in one way I have had the tank out 4 times and even reinstalled old sending unit when I did gauge went past full when there was only 5 gal. of gas in tank I am looking for suggestions all help will be appreciated