keefski

i just recently got a 2000 S4 and noticed some strange things about the gas tank/gauge. i filled up the car the other day when the gas light turned on (tank was almost empty). i couldn't get more than 13 gallons in the tank. pump kept cutting off. i get in the car and the tank reads full. it take me 200 some miles to empty the tank. which was about 17 mpg (OK). this has happened to me whenver I fill up. is my gas gauge just wrong and i still have 4 gallons even when the gas light is on? what could be this problem

DocSlow (Mini Pig)

I filled up with 15 gallons yesterday and the computer said 10 miles left

O.W. Kenobi

Run it past zero miles left a few times and watch how much gas you can put in. Anything close to 16 gallons, and you're finally running it close to empty.

You think this car is bad? I used to drive 60-70 miles all the time when the needle in my old 1985 Saab 900S was resting on empty.

keefski

so you think that even though the computer tells me I have 10 miles left, there could still be 3 gallons in the tank?

so i prob shouldn't worry about this then?

Toy_Guy

I'm the experimental sort, and have run the tank out at least 4 times.

Please correct me, knowlegdable folks, but I think the nominal is 16.3 gallons capacity.

I filled up with 16.828 gallons last January, but I've seen as much as 17.5 gallons due to pump inaccuracies, no doubt. The gas stations will always be on the borderline of non-conforming. It's obvious.

The deal is: the computer runs a running average of the fuel mileage and at 35 miles to go, the fuel light comes on. If you've been running hard, you have more gas remaining. If highway/easy, you have less remaining. It tries to predict.

In NO case will you run out of gas at the zero mark. It seems to range somewhere from 13 to 25 miles beyond zero based upon my experience...somewhere a little bit less than 1 gallon after zero.

Normal way-below-zero fillup is at 15.5 gallons, so your experience jives quite well.

Craig<ul><li><a href="https://forums.audiworld.com/s4/msgs/1128944.phtml">https://forums.audiworld.com/s4/msgs/1128944.phtml</a</li></ul>

Mark P

and thus sometimes it'll come on when you have 25, 30, 35, etc miles remaining. If you've been driving hard over the previous 20 miles (I believe that's the measure), you'll be averaging a low MPG, so when your light comes on saying you have X gals of gas left, it'll correspond to a lower miles remaining. Whereas if you have been driving conservatively, you'll have more miles remaining on that same X amount of gas since you've been getting better MPG for the previous 20 miles.

I'll have to keep an eye on this, but I'm almost positive it's the case since I recall wondering originally why my light came on when I had different numbers of miles remaining

DocSlow (Mini Pig)

I believe you are correct. Sometimes mine comes on with 25 left and sometimes with 35 left.

Toddorbert

most I ever filled up was 14.5 gal, and that was after driving 15 miles after 0.

AxelS4

as far as I know, all US S4s had the 64 liter (16.4 gallon) tank. The early European S4s had the old A4 2.8q tank which was smaller. The mystery you describe most likely is a corroded contact on the fuel sender. The sender itself is ok, just the stupid contacts corrode and therefore make the ECU think you are running out of fuel. The is a tech section that describes how to remove and reinstall the fuel sender.