"Out Of Fuel" warning lamp at +1/4 tank...what the f*?

[Gerard <gerard@poboxes.com>]

Hi!

I've been an owner of a 1990 Audi Turbo (South African Audi 200
Turbo as far as I can tell) for the past 3 months. The car is not in
the best of shapes, but I'm working on it and haven't saved a penny
since I got it.

The problem I'd like to find a solution to is as follows. These cars
have an auto-check system in the middle of the instrument cluster,
between RPM-dial and speedo. It just checks electricals and other
stuff and displays the appropriate warning on the LCD screen. When I
got the car I could see the LCD panel was working, but its back
lighting wasn't. This I've had repaired (and that in itself is another
long story. :)). But for the past few weeks (or a month in fact) I
have been getting the little fuel pump symbol. This happens when I get
to just over 1/4 tank of fuel left. Below 1/4 tank it will happen on
almost every left hand turn. The fuel gauge, separate from the auto-
check system, works fine. It doesn't over-read, by that I mean if it
shows 1/4 tank it is in fact in red which would mean the auto-check
was working but the gauge wasn't. It in fact does work as I have driven
the car in the red for a while (a scary thing I do very often as I am
right on the edge of bankruptcy (sp??) 'cos I bought my Turbo a week
before I got my job ;-> ).

Some people have told me to replace the entire auto-check system.
Others have said it might be a problem with the float in the tank.
One guy who works for a motor electrical company told me he can fix
it for US$125, but he is about 400km away and he wants me to remove the
cluster unit and send it to him for about 3-7 days, which means I either
have no transport for a while or I drive without instruments (that'd
be fun! :)). VW/Audi South Africa want US$2,500 for the auto-check
display system and the circuit board at the back of the instrument
cluster, this does not including the instruments. A 2nd hand instrument
cluster can be had for US$125 to US$250 from a boneyard and a
Audi/Porsche dismantler, respectively.

Now, the guy who said he could fix it if I sent it to him told me that
there is just something at the back of the cluster/auto-checker that
has to be adjusted as the auto-check system should then monitor the
signal from the float in a different way so that it doesn't go off so
soon. But for US$125 it seems a bit extreme for doing such a simple
thing.

So, has anybody else on this list had problems with the fuel-pump
sign coming on with the fuel gauge needle well away from the empty?
Oh yes, funny thing is that the "estimated fuel range" on the display
computer reads in accordance with the fuel gauge. I mean, when the
fuel-pump sign "out-of-fuel" comes on the fuel gauge is sitting over
1/4 tank and the estimated fuel range is over 200km.

What at the back of the instrument cluster controls when the
"out-of-fuel" signal fires? It has to be some rheostat of some sorts,
doesn't it?

Any help would be appreciate. Thanks. :)

Cheers!

G.

-- 
"a thousand miles from here, there is another person smiling"
name   : gerard van vught
tel    : +27-57-912 2658 (w) / 082 923 9609 (cell)
url    : http://www.acenet.co.za/homepages/gerard/
e-mail : gerard@poboxes.com  / han.solo@galaxycorp.com
         gerard@acenet.co.za / van_vught@frg.issi.co.za