Fuel Gauge Problem
 

I have 02 Quattro coupe with 67K miles, which I bought used (I'm third owner). I've had car for 9 months, and drive it about once a week. Instrument cluster was replaced by Audi dealer just before I bought the car in Mar. At one point a few months ago after topping off, and while at idle, the gauge dropped to zero and an alarm sounded (steady beep). After five seconds or so, the alarm quit and the gauge returned to full (position before the alarm). From that point on, gauge is inaccurate. Now, after filling, fuel gauge reads full for about 200 miles, and then will move slowly to half-full. For the next 100 miles, needle will drop to 3/8 full and no further. I just topped tank and it took 14.4 gals. I've gone through car's maintenance history and it's never had a fuel gauge problem. I'm unsure what to do. I hate to have to take it to the Audi dealer. I have a local mechanic but if there is any chance this is due to the instrument cluster replacement then I suppose I do have to take it to the dealer. Any help appreciated.

Sounds like the senders need cleaning or replacing. They get corroded (ethanol in the fuel is a culprit). And it's not just Audis. My Ford pickup has this problem.

You can try the "techron fuel system cleaner" trick . Add a couple of bottles of this stuff to a several full tanks of gas. It sometimes cleans up the senders.

Remove both senders and clean with a pink pearl eraser. About half way down the page. If you DIY it's a couple of gaskets.

https://www.audiworld.com/forums/sho...php?p=16766762

FYI: Vag.com is a great piece of software to have if you plan on keeping your car for any length of time. VAG.com can test the cluster for you.

FSU's
 

In my Roadster, I have had the Fuel sending units out (x2). Dont forget to buy new gaskets prior to opening your tank. Your existing ones will NOT reseal.

The fuel sending units get worn from the float arm rubbing on them constantly. Once you remove the arm and FSU from the tank sometimes you can clean them. Be careful! The FSU is made by VDO and is printed on ceremic and is easy to break. If you pull it out and see that the pads are gunked up, just use a light abrasive like scotch brite and water to clean. If the pads are worn off, you will need to replace.

Good luck.

Thanks
 

AudiMick and CartoonDog, I appreciate the information. I'll use the Techron now to see if I'm lucky. Maybe it will do the trick. I've sent the information you gave me to my mechanic. If we have to pull the sending units then he'll know exactly what to do. He'll also be able to run Vag.com check for me on the instrument cluster. If it's bad I can take the car to the dealer. I checked with them today and the cluster is still under warranty. You recommend that I purchase my own Vag.com, which I will do since I plan to keep this car until I kick the bucket. But can you recommend to me what or which to buy? I'd rather bypass the learning curve part of this process and use whatever it is that you recommend. Again, thanks for your help. Invaluable.

Vag com
 

The Ross Vag com is nice, and it will allow to easily test your dash/fuel gauge. I would get the USB version. I have an earlier serial version which is kinda a pain, but does work. The Vag com will help you solve problems yourself instead of guessing or taking it to a mechanic and have him guess at your expense. Do note, it is not a magical oracle and will require some trouble shooting and experience. One of the best features is that you can clear faults- if they come back you have a problem, if they dont your good!

I would just plan to change your FSU, and save yourself some bucks. Its about a two beer job, say 3hrs. All said and done, no more than $300 bucks including parts.

Goodluck.

Mine did that.

Would show empty with 5 gallons in tank.

First time they replaced fuel sender.

2nd time they replaced cluster under recall.

Its doing it a third time, my guess is they will replace cluster with a stock cluster that has the same inherent problem.

It will work for a while then go bad again.

You said they replaced " fuel sender".

There are (2) on a quattro, is your TT FWD?

Follow-up re my problem with fuel level sensors: Fixed!!! The Techron did the trick. I actually used two bottles of the Techron and two bottles of a Gumout equivalent, filling the tank with Chevron gasoline each of the four times. Again, thanks for the tip. Without the Forum I would have had to have these sensors replaced unnecessarily.

SOrry for late follow up.

I did not know there were 2 fuel senders.

I had it replaced again and it fixed it. Between cluster and FS it required 3 repairs in 3 years. All under warranties thank goodness.

Does anyone know the part numbers for the gaskets that need to be replaced?
My car does the exact same thing and I would like to try and pull the senders to see if I can clean them.