2001 sunfire fuel gauge issues

It's probably the float on the fuel pump.pull the pump and clean or just replace the fuel pump and float.

The fuel level indicating system is a magnetic type system, which consists of the sending unit located in the fuel tank, an anti-slosh module located on the back of the instrument cluster, and a fuel gauge located in the instrument cluster. The sending unit changes resistance according to the level of fuel in the fuel tank, which varies the current flow through the gauge.The pointer position varies proportionately to the current flow. In this system, the sending unit resistance is low (22 ohms) when the fuel level is low and high( 145 ohms) when the fuel level is high. The pointer of the magnetic gauge remains in position when the ignition is turned to the Off position. On some models, an anti-slosh module is used to dampen out fluctuating fuel signals from the sender. Some vehicles are equipped with a low fuel warning indicator. The anti-slosh module will also actuate the low fuel indicator when the fuel level in the tank reaches 1/16 to 1/8 full.


Do your other gauges/warning indicators work properly with the ignition on? If not, check for power at the fuse panel/fuses.

If they do then partially remove your cluster with connector still installed and check for voltage at cluster connector and gauge. Check continuity of cluster and gauge for ground.

Sometimes the anti-slosh module (if installed) goes bad in the Grand Marquis but not likely.

Sender troubleshooting:

1. Perform test with resistors as follows:

1. Disconnect wiring connector at sender unit, then connect resistor between gauge lead and a suitable ground.
2. Turn ignition switch to On position.
3. With 145 ohm resistor, the gauge pointer should contact the Full mark.
4. With 22 ohm resistor, the gauge pointer should contact the Empty mark.

1. Perform test with fuel sender of known quality as follows:

1. Turn ignition to Off position.
2. Disconnect wiring connector from sender and connect it to test sender.
3. Move float rod away from fuel filter against Full stop position. Wait approximately 30 seconds, then turn ignition switch to On position. The gauge should read on or above the Full mark.
4. Move float rod toward fuel filter against Empty stop position. Turn ignition switch to Off position. Wait approximately 30 seconds, then turn ignition switch to On position. The gauge should read on or below the Empty mark. If gauge works properly replace sender, which involves dropping fuel tank.
   

If the sending unit was connected and grounded, I would guess the gauge in the cluster is faulty.

Ensure that all of the wire connections are clean, secure and corrosion-free.

2 Check your fuel gauge fuse if the gauge's indicator stays on empty when your turn on the ignition. If the fuse is good, join the sending unit connector to ground. Replace the sending unit if the gauge indictor moves to the full line.

3 Ground the terminal located on the back of the fuel gauge with a jumper wire if the indicator doesn't move. If it does move, consider replacing the wire between the fuel gauge and the sending unit. A poor ground is frequently responsible for fuel gauge problems.

4 Release the wire that connects to the fuel tank's sending unit. Confirm that there's no worn insulation that would permit wire contact to the body or frame. A fuel gauge reading of full generally indicates a problem with the tank unit, not the wiring.

disconect wire from temp sending unit
if that stops gauge moving , u most likely need to replace sender unit
they are not expensive
if after replacing sender unit gauge still does it, u need to replace the gauge

at the wiring at gauge you can ground out if gas needle moves it in the float .

I tell you for sure that is the sensor problem from gearbox.the sensor, or the wire. The fuel gauge is connected to the gearbox because is not very nice to corner and the fuel gauge go up and down. Now because the fuel gauge "didn't know" how many miles did you made, he is moving up and down. All recent cars have the same problem, and had the same problem on my girlfriend Golf 4. It was the wire. The mecanic forgot to put it back.

SOUND LIKE FUEL GAUGE IS FAULTY.IF YOU REPLACED FUEL PUMP ASSEMBLY WITH NEW FUEL LEVEL SENDING UNIT.PROBLEM IS IN THE GAUGES.

Hello mcammdf.
To properly test the fuel gauge circuit you will need to check the purple wire at the connector to the fuel tank.
Run a wire from the purple wire at the connector to body ground. If the gauge moves when you ground it the circuit to that point is good.
These cars are noted for fuel gauge problems and most probably the issue will be the sending unit in the fuel tank.

KL

Dashboard gauges have a wiring problem. Most Sunfires have these especially late models. It's a common defect. While the gauges will run fine most of the time, the primary instigator is heat. The more the car heats up inside the cabin, the more the gauges will stick. So keep the inside cool, and you'll be fine. Trying to replace with Chevrolet Cobalt gauges. I'll tell you if they work.