divanian

I have an 99 a6 avante just purchased 1st of Nov. After washing the car by hand, I went to start the car but the battery was dead. Had enough juice to run lights, radio, etc. but not enough to crank it over all the way. I noticed that the trip odometer and other functions reset to zero. After I got a jump from Audi 24 hr roadside service, the gas guage suddenly, before my eyes and ears,(buzzer sounded)went from over a 1/4 tank and 80 miles left, to reserve with 15 miles left. Another mile later it jumped down to flat empty with 0 miles left on the odometer. Anyway I made it home, recharged the battery for 4 hours, then tried to start it again, but it was deader than a doornail (not enough juice to turn it over). Obviously the alternator is charging because I wouldn't have been able to drive around with lights on for the 5 miles that I did.

I've heard on this forum of the problems with the fuel sending units going bad. Do you think this is related to the battery problem (varying voltage)or was it just a coinicidence? Why did the computer readings reset themselves to zero?

Obviously the guage was reading too low since I was able to drive 5 miles with zero gas according to computer. I thought the fuel guage problem always showed more gas than was actually in it.

Do the dealers usually stock the faulty fuel guage part? It seems that I have been reading on this forum, the long wait that occurs waiting for parts to arrive.

Allen

Unless your Avante is a Quattro, it probably isn't the fuel gauge. My dealer had all the parts when I took it in. I never had any battery problems only fuel gauge probs. Let us know what happens.

PeterV

I have a '00 2.7T mfg 7/'99 and after filling up the tank the gas guage read full for 3 days. Then went where it wanted to. I have the parts on order My dealer said that the 2.7's havent shown this problem but does know of the problem. The fuel tank has 3 senders in it and a ckt board combines the inputs to give a read out. I understand that the fuel tank is a molded design with a very irregular pattern.
PeterV watching the trip meter carefully.

divanian

Yes it is a quattro. Ccharged the battery overnight and this morning it did barely start. the battery is definitely weak. Gas guage went back to where it was before the problem but I don't know for how long.

JOB

your near-dead battery places such a load on the alternator that, while running, your system voltage is low enough to make some aspects of the car's electronics/sensors/computers somewhat flakey/erratic? I believe that my running voltage (with an apparently good battery) is about 14 - 15 volts (per guage in dashboard cluster).

What's your running voltage? If it's low/marginal, why not replace your battery and see what happens?

(This advice assumes that your alternator is OK, as you suggested in your post.)

Steve Bollinger

I drove my 2.7T for over 20 miles with the gauge on empty and the miles-to-empty reading 0.

The system is rigged to say its empty when it has 2.1 gallons left. It even says this in the manual.

So just because your gauge reads empty and the car still runs doesn't mean the gauge is reading incorrectly.

divanian

The guage always shows around 14.3 to 14.7. Now my Bose concert stereo shows safe on the display and won't let me turn it on. I'll have to look in the manual on how to reset that. the electronics seem to be very sensitive to voltage drops. I hope this doesn't affect some critical electronic components in any way.

divanian

Got the avante back today. Turns out that it was just a dead battery with some dead cells. all of the errant reading on odometers and fuel guage were caused by minor voltage surges and drops. anyway everything checked out ok.