Erratic Fuel Gauge
 

I have a 1998 A6 2.8 Quattro Avant ( uk car) with 150,000 miles in very good
condition & full history. Lately the fuel gauge has been playing up, showing
full for 150+ miles then dropping rapidly until it gets to half, if I then
fill it up I can get 50-55 litres in (70 litre tank) so obviously something
is wrong. I have removed the tank cover and operated the float by hand and
the gauge does not go below half even when on the bottom of its travel,
anyone got any suggestions as to whether its the tank unit or the gauge, or
possibly a voltage regulator somewhere, (everything else works fine). If its
the tank unit should I try a second-hand one as I imagine that to by a new
Audi part means taking out another mortgage to pay for it.

Any help would be appreciated

Graham

"Graham Humphreys" wrote
> I have a 1998 A6 2.8 Quattro Avant ( uk car) with 150,000 miles in
very good
> condition & full history. Lately the fuel gauge has been playing up,

This is actually quite common on many Audis. Most of the time, the fuel
sending unit needs replacing. See if this link can help you:

http://www.robsaudiworld.com/fuelrepair.htm


Second possibility is faulty gauge, but I'd start with the FSU first.

Good luck,

Pete

"Pete" wrote

> This is actually quite common on many Audis. Most of the time, the
fuel
> sending unit needs replacing.

I also forgot to mention that in the US, somewhere around year 2000,
there was a whole Audi customer service action that included free
replacement of fuel sending units with the updated ones (apparently the
older ones on '96-'99 model years were prone to premature failures).
This was specifically for the A6. So, you may want to call Audi
Customer Relations in the UK and see if they had something similar going
and if so, they should fix it for free, even if you're no longer under
warranty.

Cheers,

Pete

Ive got the same model tho its a 99 year. 112k miles and had it since new.

The fault is exactly the same.

Audi 1st replaced the sender at 35k miles for free. It failed again at 80k
and they wanted £150 to put a new sender in. Ive just lived with it and
always use the trip meter to calculate tank.

The 2.8 will do 328 miles on a full talk before it splutters to a halt!
(and I know that for sure as it happened to me)

Now I always carry a spare gallon in the back and always fill up when I get
to 300 on the trip meter.

Ive seen the post already shown about the repair, Im just wary of opening up
the fuel tank due to the obvious fire risk. Plus if you dont have the right
tools and dont seal it properly afterwards you will have a petrol smell
inthe car for ever, as the hatch is below the rear seat cusion.

Cheers,
John.

>
> Now I always carry a spare gallon in the back and always fill up when I get
> to 300 on the trip meter.
>
> Ive seen the post already shown about the repair, Im just wary of opening up
> the fuel tank due to the obvious fire risk.

I would be more worried about fire risk by carrying the gallon in your
trunk than opening the tank access.

If it is anything like the tank in my '91 100q (which I think it is)
access is quite easy and wouldn't require any special tools. Just wait
until your tank is nearly empty to do the job.

Plus if you dont have the right
> tools and dont seal it properly afterwards you will have a petrol smell
> inthe car for ever, as the hatch is below the rear seat cusion.

The access has a seal and should not be a problem.

>
> Cheers,
> John.
>
>