Im the guy with the gauge problem,Ive asked questions before,here is where i stand.I had my mechanic try and figure it out,he thinks it might be in the cluster itself,could this be true,Im not getting any reading on my gauge,when I check for power back at the sending unit,i get nothing,I could be doing it wrong,its expensive trying to get it fixed,Im living on disability,Im 100% dis. vet and that doesnt go far,so If anyone could help me,i would sure appreciate it,thats the only thing left for problems on my car,but its a big one, PLEASE HELP

 

Checking for "power" on the fuel sender wire will not work - the fuel level sender circuit works off of resistance to ground. You should find another mechanic...get your money back if you already payed out.

I doubt you have an electrical problem at the cluster but you should check the sender's functionality first. Below is a picture of fuel level/pump assembly off an early c4. The "pink" wire in the picture goes to the fuel level sender - this sender is where the resistance of circuit is altered by the relation of the fuel's actual level (amount of fuel in the tank). You do not need to pull this entire assembly out of the tank but you will need to disconnect the electrical connector that is pictured.

Using a volt meter set on an "ohms" setting you should be able to check for resistance across the sender circuit. Connect one of the volt meter's probes to the "black" wire of the connector and the other to the "pink" wire. Report back what your resistance reading is. You may want to double check in your FSM (factory service manual) to confirm that the wire colors I'm giving you are in fact correct.





Note: about a month or so ago, I had what I thought was about 1/4 tank of gas - the car started missing and cutting out out of no where. I pulled off to the side of the road, cycled the key, tried to restart it, scratched my head and rechecked the fuel gauge....thing read empty all the sudden the gauge was now reading "empty" Turned out I had gotten some really really old watered down 93 octane fuel from a super remote gas station that doesn't sell much high octane stuff due to the current cost of it - anyway the contaminates in the fuel messed with the sender's contacts and gave a false reading. My tank was empty at that point so I through in a can of "heet" and some good fresh gas and everything returned to working like normal.

The reason I shared this story is because it is possible that your problem may be a super simple one - if you have more information (background history/when the problem started) that might be relevant or related to your problem - post it up.

 

Hey Engle I did what you said,I hooked one probe on the black wire on the sending unit and the other probe on the pink wire on the sending unit,is this the way you wanted me to do it,if so it read 0.02 if I did it right. let me know what you think,and than take me to the next step,thanks Engle for your help.

 

~"0" means your cluster's gauge should have been reading "empty" when the tank had fuel in it. It should read 90 ohm when the tank is "full".
Again - if you haven't already, consult your FSM for your specific year to ensure you are on the correct wires

If you had a 50 - 90 ohm resistor you could put that across the ground wire and the wire that leads back to the cluster for the fuel gauge (the other end of the connector) to see if the fuel segment of the LCD shows any change in "level". With the resister in place and the cluster powered up - it will take a few seconds for the fuel level segment on the cluster to register any type of change...this is normal.

If the cluster works then it would be time to pull the fuel pump assembly out of the tank and take a look. It could be that you have a shorted wire(s), a float problem, or/and the sender's contact points need to be cleaned up and/or replaced.

Still haven't heard any history or what may have caused the problem in the first place.