Fuel gauge wont work

[65cobra]

Ok, I have a 92 LX and the fuel gauge reads empty all the time, and to you smart asses yes it does have fuel in the tank . Today I dropped the tank to install a holley fuel pump, while I had the tank off I replaced the sending unit thinking this was the problem. Well it wasn't because It still reads empty. Does anyone know what the problem could be? When the car is off the gauge reads 1/4 tank, when it's running it drops down to Empty. Any help would be greatly appreciated.
Thanks

 

[HISSIN50]

i will toss an idea out - im not sure if the mis-function of the anti-slosh module would create the problem you have. im sure someone knows, but i wanted to suggest it for the smarter folks to contemplate.
also, could the sender wire be shorting out?
good luck.

 

[393Bird]

The guage movement is dependent on the amount of resistance to ground the sending unit allows. Late model Fords use 20 ohm for Empty, and 130 ohm for Full. To prevent eradic movement, there is a anti slosh board that requires a steady reading from the sending unit for a preset time, before the guage responds. This complicates trouble shooting it. The problem could be a defective anti slosh board, or a bad wire or connection. You will have to chech it at each connection. You need to know which wire is the hot wire from the guage to the sending unit, and which is the return ground wire.

 

[65cobra]

I know in some cases the sending unit gets stuck in one position and this will give you a false reading. I guess there could be a short in the line but I was hopeing this was a common problem with an easy fix.

 

[bullitstang1313]

393Bird is correct. According to Mitchell On Demand, an automotive repair program i have, you can test to see if your gauge is the problem or if its your sending unit. You can test the sending unit by measuring the resistance with an Ohmmeter. Its should read 22 Ohms when empty and 145 Ohms when full. According to the tech, you can hook a 22 Ohm resistor to the wire that goes to the gauge between harness connector Yellow/White wire terminal and ground and the gauge will read empty. If you hook a 145 Ohm resistor to the gauge it will read at or above full. If the gauge does not respond as indicated you may need to replace gauge. If the gauge does not respond correctly remove instrument cluster and inspect flexible printed circuit for opens. If circuit is okay remove anti-slosh module. Using a jumper wire, connect the resistor directly to fuel gauge "S" terminal on rear of cluster and connect the cluster to the 2 harness connectors. If the gauge reads correctly then the anti-slosh module needs replace. Doing this test can actually calibrate the fuel gauge, so this may solve your problem. I'm getting ready to do it to my 87 stang. Good luck to you, hope this helps.

 

[Notchbck93]

Where is this anti- slosh module located? I have a 93 notch with a fuel gauge that works when it feels like it and its driven me nuts

 

[HISSIN50]

393 and Bullitt, great info.
i think the anti slosh module/board is behind the fuel gauge (in that vicinity). im sure the experts above will know for sure. good luck.

 

[glock]

I just had this fixed. The slosh module is a little chip that plugs into the back of the instrument cluster. it's about 1.5" square and has, by today's electronic standards, some large chips and components on it. It's purpose is to take the varying readings from the sender and to average them out so you don't see needle jump when accelerating etc. When mine wasn't working, it would bounce slightly, but not vary more than 1/16th of a tank. If your gauge is really bouncing, then it might not be the slosh module, perhaps a faulty connection etc. Hope this helps.