Gas Gauage 1991 Cavalier

it will help if you tell us what kind of car it is and dose this problem happen after you fill it while the car is running or is it off ?

You probably have a bad sending unit for the fuel level in the tank. this would cause the gauge to be erratic when the level is below 1/2 tank and the float is moving around much more than when full. The oil pressure gauge problem could be caused buy a loose wire connection or a faulty sending unit.

The float is what measures your gas levels. It is controlled electronically. There might be a loose wire or it could be going bad. You can usually get to them by moving the back seat. Others, the gas tank has to be pulled off. I hope this helps you.

sounds like its time for a new sendinding unit, this is the part that hold the fuelpump inside the tank, and has a float arm, this is what tell you how much gas is in the tank, heres a picture of it,this comes with everything even the pump,also make sure to wire in the new connector,these trucks have connector problem,good luck.also check the ground that go to that connector, follow them,may go to rear frame on the leftside, remove and clean them.

I own two 1993 960s and on one the gas gauge sits on 0 until I thump (hard) the plastic lens in front of the gauage in the instrument panel. It is most certainly due to a cold solder or cracked solder joint. Can be a corroided contact.

Thump the gas gauge arrow like I do when it is registering 0. If it does not move then it is the sender in the tank that has a flat spot.

William White

The fuel tank probably got filled too much gas, and the float got bent, or the float was not installed properly, when the fuel pump was installed.

Well that tells me that someone installed the wrong fuel level sensor. Your going to have to drop the tank and pull the pump and float assymbly out. Then go to a parts store and get a sending unit that has the opposite resistance of that sending unit. Just wait until the tank is empty so its a lot lighter. You can call the parts store or go down and see if there is multiple sending units. The sending units work by resistance, when the tank is full the float moves up and turns a wheel in the sending unit, which either removes or increases the resistance causing the gauge to lower. The sending units either give full resistance at full or no resistance at full and then changes as the level goes down until it does the opposite at empty.

it sounds like the level sensor on the sender (fuel pick up pipe in the fuel tank) is getting stuck. the level sensor is a float that is attached to the sender, and you will need to remove the fuel tank to get to it.

hope this helps.

it will be your float in your tank, you have to drop the tank and replace the float.

you have a bad sending unit inside your tank.
the resistance of the potentiometer inside is broke on the half tank part.

you have to replace it.

tnx 4 using fixya.

drcool