Dual fuel pumps, was: Re: C'mon, man-help!

[Andrei Talalaevskii <andrei@insti.physics.sunysb.edu>]

I have a first-hand experience with both pumps on my Golf that has this 
dual pump system.

Contrary to the wide-spread opinion that in-tank pump fails first, my
main pump failed while in-tank was fine. It was about three years ago.
"Luckily" my friend had just totaled his Fox and I put his pump to my
Golf. The Fox's pump is a little different from Golf's but we managed to
fit it. It is still there (knock on wood). 

This fall my main pump started buzzing like hell again. I thought that
it's time to pay the price for installing a used pump three years ago and
was prepared to spend about $200 for a new pump. One thing puzzled me
though. The buzz and the car seemed to work OK when I topped of the tank
and stayed this way till I used some fuel (1/2 to 3/4) when problems
returned. People who I usually turn for advise where also puzzled since
they were Audi nuts (like Phil) and didn't know about this two pump system
used in VW's (like Phil :). The pressure the pump gives is incomparable to
the pressure difference caused by several cm of gasoline. So, why would 
that be?

I described the symptoms to Rick http://www.importpartsspec.com (a place I
highly recommend btw) and he told me that these are typical symptoms of
failing auxiliary fp. ($40 from him). I still feel a little guilty because
I put the pump from the same Fox in my Golf and Rick didn't get any extra
business for giving me such a helpful advise. Well, he is one of the first
I turn when I need to buy something for my Golf or 4kq.

Hope that story was amusing...

Andrei