more fuel gauge probs.

me and you are in the same boat, it reads above full all the time, except when im low on gas then it goes down almost to E. i about to go tinker with it in my new acquired work garage, good luck!

According to my diagrams there is a slosh module located somewhere on the instrument cluster assembly, but I don't know the symptoms of a bad module. Maybe you have a bad/loose connection at the gauge itself?

Hey mine used to have a bad attitude where I would work fine for months! then it would go right to empty or it would be full and old read half a tank, or be completely bone dry and read 1/4! lol There have always been ghosts in the machine!

waht i did was i filled up my mustang reset the trip meter, then ran it till she started to stall on me (indicating low gas) and noted the miles on the trip meter.......... it gets me darn close most of the time, cause it ussually takes about the same amount of gas each time i get around that number on my trip meter.


my family is cursed with cars that have gauges that don't work, every car my dad has owned has had the same problem and all 4 that are in our household are all shot

i am having this exact problem and i hate ditching the 100 bucks for a sending unit and all the time to do it when it may not solve the problem... anybody ever figure anything about this out....

Here's some help, but not much. I still haven't figured out a 100% accurate test for the anti-slosh module.




The red/yellow wire (power supply to gauge & sender) should have 12 volts when the ignition is in the start or Run position.

All resistance measurements should be made with the power off.

Note from bstrd86 - 86 and older fuel tank sender units are 73 ohms empty, 8-12 ohms full.

The yellow/white wire will show a voltage that varies with the movement of the float on the sender unit. To test the sender, set your Ohmmeter or DVM on low Ohms. Then disconnect the sender and connect the Ohmmeter or DVM to the yellow/white and black wires from the sender unit. Move the float arm while watching the Ohmmeter or DVM. You should see the reading change from 22 to 145 ohms +/- 10%.

If the Ohmmeter or DVM resistance readings are way off, replace the tank sender unit.

Use extreme caution if you do the next step. Fumes from the gas tank can easily ignite and cause a fire or explosion.
With the sender unit out of the tank and connected to the body wiring harness, turn the ignition switch to the Run position. Move the float arm and the fuel gauge indicator should move. If you are very careful, you can use a pair of safety pins inserted in the connector for the yellow/white and black wires to measure the voltage as you move the float arm. The voltage will change, but I have no specs for what it should be.
Do not short the safety pins together or to ground. If you do, you may damage the anti-slosh module or crate a spark. A spark with the fuel tank open could cause a fire or an explosion.

If the voltage does not change and the tanks sender passed the resistance tests, the anti-slosh module or gauge is bad.