New fuel pump installed...boy is it loud!!!

Fred Munro munrof at
Wed Aug 7 23:59:44 EDT 2002

Hi Craig;

The Czech pumps are noisy and IMO not as well built as the original German
pumps. I replaced the pump in my '91 200q ( I think it's the same pump as
in your car) with a Czech built pump and it was noisy, but not as noisy as
you are describing. I didn't have the 3214 tool, so I took it to the dealer
to have it installed. The tech took a look at the pump and said "Hmm. Built
in my home country. Good luck - it'll be noisy!" He was right.
It sounds like you have a defective pump or something is blocking the pump
inlet or outlet. You didn't leave a rag floating around in there, did you?
You may want to change the fuel filter - you may have stirred up the bottom
sludge trying to clean it out and it may have plugged the filter. If that
doesn't help, pull the pump and check the inlet screen for pluggage. If it
is clear, return the pump as defective. The sputtering engine indicates it
is not getting enough fuel.
I seem to recall a few posts several years back with listers who had
replaced the Bosch pumps with Piersburg?? pumps. Apparently the in-tank
mount had to be modified. You might check out a pump for the UrS4 - I
recall when I was sourcing the pump for my 200q the S4 pump was different
(and considerably cheaper).

Good luck! It's a RPITA when you put the work into a repair and you still
have a problem.


Fred Munro
'94 S4

-----Original Message-----
From:	Craig D. Niederst [SMTP:niederst at]
Sent:	Wednesday, August 07, 2002 9:32 PM
To:	Quattro List; *12V List
Subject:	New fuel pump installed...boy is it loud!!!

I just finished installing the new Bosch fuel pump into my '92 100S. The
3214 tool did the trick in getting the pump out. I cleaned up the screen on
the assembly, and cleaned up as much crap as I could from the inside of the
plastic housing in the tank. Got the new pump installed, reconnected all
hoses and electrical connections, and filled the tank with ~4 gallons of
gas. Reconnected the battery, turned on the ignition to hear the fuel pump
engage quietly (fuel gauge read a tad under 1/4 tank), and after a bit of
cranking, she fired right up. After verifying that nothing was leaking, I
headed to the nearest gas station to fill the tank the rest of the way up.
On the way up a steep hill, the car began to sputter badly, to the point I
had to pull off the road. I shut the car off, and it refired just fine. I
got to the gas station, filled the tank up, and when I tried to restart the
car, it started, but sputtered for about 5 seconds. I drove the car home
with no problems, but in the driveway, I could hear the fuel pump buzzing
very loudly. Upon crawling under the car, the buzzing was incredibly loud
and inconsistent (would buzz with pulses of louder buzzing). My old fuel
pump (also a Bosch unit, original to the car) never made a buzzing sound
like this, and was generally very quiet. When I start the car, the pump
quiet for about 30 seconds, and then the buzzing begins. The tank did have
some crud in the bottom of it, but nothing that could get through the
screen. I did not change the fuel filter (I did it about a year ago @ 90k,
has 99k on it now), but was planning on doing it when I finished the first
tank of gas after the pump change. With the pump sounding as it does, it
sounds like it is going to fail again real soon. Any ideas on what
Bad fuel pump out of the box (it was made in the Czech Republic if that

'92 100S (99k)
'86 CGT (214k)

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