fuel pump story - long

["Jason T. Douglas" <jdouglas@mitre.org>]

Here's a problem that stranded me twice.  I've not read about on this 
list before.

After reading this list for a coupla years I've reached the point where I 
feel pretty confident about what failures are likely to occur on my '86 
5000S.  You know, the usual page long litany of woe.  Well, I've been 
there and done most of those.  What with all these typical Audi problems, 
it is always a surprise when a normal failure, that is a failure in a 
normally robust part or system occurs.  It is almost as if Audis have 
their standard afflictions and are not supposed to break in the ways that 
other cars do.  Well, it ain't necessarily so...

About two months ago I was driving through the I-64 tunnel coming out of 
Norfolk, VA.  It was Friday afternoon and I was looking forward to 
getting home to see the family after a week away.  The engine just died 
at 60 mph.  My car is a stick, so I started cranking it before stopping 
and got it running again.  Then it died again.  This happened twice 
before we got to natural daylight, and I can tell you that the folks 
behind me weren't too happy. :-(

As a long time Audi owner and list reader, I had two tool boxes in the 
trunk.  The obvious thought was a fuel problem, but there was enough 
pressure at the filter input to shoot gas over the front bumper when I 
barely cracked open the fuel line.  No fuel came out of a randomly 
selected injector line, however.

Trick - jumper the fuel pump relay (you can use a paper clip!) 
and go listen to the in tank pump (stick your head under the bumper).

After replacing the filter, there was still no luck.  To make a long 
story short, the pump had failed and was pressurizing the fuel, but not 
at a high enough pressure (5+ bars).

The sequel to the story is that the car died on I-95 in North Caroline 
yesterday afternoon with exactly the same symptoms.  I had to get towed 
40 miles to get it to a shop competent to work on it.  Once again, the 
pressure was insufficient, but the fuel that came out of the pressure 
test port on the fuel distributor was *foamy*.  It turns out, to my 
greatest embarrassment, that I was merely out of gas (and a hundred 
bux!).  The tank was perfectly empty even though the guage said 1/4 (I 
don't usually run it that low, but I was running a bottle of techron 
through it at the time).  As far as I can guess, the shop that replaced 
the pump bent the arm the fuel guage sender float rides on, so that the 
guage reads 1/4 when it is empty!

BTW, the list price for a pump is something like $350, but you can get 
them through the mail for half that.  

Jason Douglas
jdouglas@mitre.org
(703) 883-7016