Fuel Gauge

[leeboy]

I have a problem with my fuel gauge. Ive done the search and found some answeres. The part on the computer that tells me how much fuel is left in the tank can vary about 100 miles lol, if im coasting or rolling it goes up a lot, and vice versa if im accelerating. Is this normal??

Also the gauge its self. I just bought the car so its all a bit new to me. It read about 1/4 tank when i bought it, but showed i had about 300 miles left in tank. put about 15 quid in to drive it home, it when up, down, up down lol all the way home. Didnt use it for a while, then when i tried it again it wouldnt move. I read some posts on here and seen the one about the tank sender, so thought, ahh, must be this, no worries, ill do it when i get time. filled it up then and it took about 30 litres, not sure of the tank cappacity, guessing its about 50 or 60 litres. The gauge wouldnt go above 3/4. Ive done about 150 miles since the fill and gauge stays in the red!!!. So i banged the dash, and it went up a bit, but not to about half or 3/4 or something but to the 1/4. The previous owner had the speedo changed due to the face falling off. So im guessing that the fitter must have damaged some wires.
Is this an easy job to do?. is my fuel computer working as it should, or is my tank sender ******ed?.

cheers

lee

[4WheelDrifter]

If the needle is sticking, then it is most likely the dial face peeling.

And yes. The range will go up and down depending on driving style.
The computer obviously calculates the range as if you will continue the way you are currently driving.

[leeboy]

cheers for the reply. Are the fuel gauges available to buy, from a non audi sorce

[HPmuirt]

I have a problem with my fuel gauge. Ive done the search and found some answeres. The part on the computer that tells me how much fuel is left in the tank can vary about 100 miles lol, if im coasting or rolling it goes up a lot, and vice versa if im accelerating. Is this normal??

lee

The computer calculates average speed, fuel consumption, range etc, based on speed readings taken every 30 meters - I think there is also a max refresh rate of once per second as well (which explains why as you coast up to your house the reading changes more slowly, but at motorway speed the change more frequent)

As for range calculation, this based on the measured fuel remaining in the tank at the time of the measurement, compared with your average fuel consumption over the last 20 miles (30Km). Therefore, to vary the range reading, you need to change your driving style for a several miles, for that new average fuel consumption to be used in the range calculation. Booting it or coasting occasionally will have no effect.

Hope this helps

Cheers n

Si

[leeboy]

nice one, thanks very much

lee

[Markarina]

IIRC the fuel tank capacity is 72 litres, which means if you let get really empty when petrol prices were high and then filled it up to the top, you needed to ring the bank quick to get the overdraft approved

[leeboy]

72 littres, holly cow lol. It shows my gauge is well screwed then lol if i could only get 30 litters in.
Today for instance the computer is saying that theres 85 miles left in the tank and ive done 160ish miles after the fill up. Even if the gauge was sticking should it still read this?

lee

[HPmuirt]

All Coupes run a 70 litre tank (about 15.4 Gallons I seem to remember).

Most folks see between 16 and 22 MPG on an urban cycle, depending on the level of lead in the right foot and their average traffic cycle: at 20MPG you should see just over 300 miles to a tank. I get between 260 and 320 miles per tank, but I have had it as low as 180 (miles fast driving and a track session) and as high as 395 miles (100 MPH cruising across Europe)

I don't normally fill up until I am well into the red and regularly take the gauge below and out of the red. My record is 30 miles after the range display on the computer said 'E' (the needle was miles below the red ) When I then brimmed the tank it took 67 litres.

The other thing to mention is that the fuel gauge in the main display can be calibrated to read full when the tank is brimmed AND the range setting on the computer display can be calibrated. That can be done from the know on the dash if you are lucky and it connects properly, otherwise you will need to dismantle the clocks to get at the pots. I seem to remember seeing an article on this somewhere...probably S2Central

Cheers n

Si

[leeboy]

thanks for the posts guys, youve clarified a lot of info

cheers

lee