1995 Audi 90 Q Fuel Cluster Guage always empty

[95Audi90Q]

I'm having problems with my fuel sensor always being on empty. I have read and think I understand that there is a part that goes into the gas tank that will have that sensor on it. I'm trying to figure out if the problem is inside the tank or in the lines to my driving cluster. My initial intention was to see if I could find where the sensor comes out of the tank and then connect it to the frame. I was hoping that would cause the circuit to complete and put my gas guage on Full. This way I can tell if it's inside the tank or outside the tank where the problem is. am I going about this the right way? Photo.jpg has a picture of my car from the passenger side rear wheel. I hope the metal container in the middle is the gas tank where this piece will be that I'm looking for. Photo(1).jpg has what I guess to be the hole from the gas tank that runs to the engine. Is this the piece I need to take apart to find the sensor to make my fuel gauge work? Thanks a lot for your help

[maineman]

Everytime I've had an issue with my fuel gauge it's been a ground in the cluster or the ignition switch.
Take your cluster out and tighten all the little nuts on the back.

Or, when you fill the car up set your trip odometer to 0 and when you get to 300 miles you should start looking for fuel.

[95Audi90Q]

Originally Posted by maineman

Everytime I've had an issue with my fuel gauge it's been a ground in the cluster or the ignition switch.
Take your cluster out and tighten all the little nuts on the back.

Or, when you fill the car up set your trip odometer to 0 and when you get to 300 miles you should start looking for fuel.

Hello maineman. How do I take out my cluster to tighten and make sure everything is corrected? Is there a DIY guide? I'm new to the car world.

Thanks

[grillage]

This post has directions for cluster removal - welcome to the car world...

http://forums.audiworld.com/showpost...23&postcount=6

[95Audi90Q]

Originally Posted by grillage

This post has directions for cluster removal - welcome to the car world...

http://forums.audiworld.com/showpost...23&postcount=6

Thanks for your help grillage! Sadly after taking out the cluster I noticed that the gas component doesn't have any input to give it any response to display. I think I'm missing parts inside their.

Do you guys have a guide I could check out or look to compare my car to the "correct" version?

[grillage]

Here's how a gauge works...

it is a really simple thing actually.

Here is a gas gauge next to a gauge with no faceplate...


The only connections on this thing are the same two posts and nuts that hold it in place...


when a current is put between the two the gas gauge moves up. I would guess that there is a potentiometer that sends a certain level of voltage depending on the level of the gas tank. If you test your gauge and it works, the next step is the level sender or perhaps as maineman said above, the ground on the cluster itself.

I used a 12v Ryobi drill battery as my power source and connected clips to the two posts for a test. click on the photo below and it'll take you to a video...

[egp320i]

The fuel level sensor is on top of the tank by the pump, access is through the black round plate inside your trunk.
This item is electronic and measures per the float device your amount of fuel and relays it to the dash.
The part is dealer only, wholesale it is around $130, retail over $200.

I have no idea what the failure rate is of this device but judging by how few have replaced it the rate must be extremely low.

With most electronic devices it either works or not. If you say your gauge is always on E this part might simply have failed.

[95Audi90Q]

Originally Posted by grillage

Here's how a gauge works...

it is a really simple thing actually.

Here is a gas gauge next to a gauge with no faceplate...


The only connections on this thing are the same two posts and nuts that hold it in place...


when a current is put between the two the gas gauge moves up. I would guess that there is a potentiometer that sends a certain level of voltage depending on the level of the gas tank. If you test your gauge and it works, the next step is the level sender or perhaps as maineman said above, the ground on the cluster itself.

I used a 12v Ryobi drill battery as my power source and connected clips to the two posts for a test. click on the photo below and it'll take you to a video...

Thank you very much for the detailed explanation. If the charge comes through the bolts on the back of the gauge, which makes sense, then my car is broken in the sense that there is nothing connected to my gauge. Do you know where I could look or try to find the two wires that send a charge to my gas gauge?

[grillage]

Remember, those posts are threaded through the circuit board. One post picks up the ground and the other the charge from the level sender.

Both come from the blue wire harness