Re: Fuel pump roulet

[QSHIPQ@aol.com]

In a message dated 97-10-14 13:11:31 EDT, you write:

<< All this talk about fuel pump noise, convinced to me to change mine on the
86 
 >5k. The beast ran fine for the first few days but now I have trouble
keeping 
 >it going after its been parked over night, after about 15 minutes of 
 >operation every thing seems to be normal which is about the same amount of 
 >time it takes me to get to my mechanic. Does the saying "If its not broken 
 >don't fix it" come into play here ? 
  >>
And another writes:
>>So...the law that "a noisy fuel pump is a fuel pump that is
>>about to fail" is one that may need to be taken with a _large_ grain of
>>salt. Certainly some (most?) fuel pumps run quietly and get noisy shortly
>>before failure, while others probably tend to run noisily for very long
>>times.
>Of course, a "very long time" for one person may be a major PITA for
>another. But since in one sense all fuel pumps can be considered as being
>"about to fail...

Some interesting thoughts, not sure I'd be content with that advice.  A fuel
pump that is noisy after install can mean one of two things.  1) the fuel
pump is noisy from the get go or 2) you have another problem in the system.
 The risk of running a 175 dollar fuel pump till it fails is this R&R (btdt
to one):
*  Rebuilt fuel head 63X = 750USD
*  New fuel injectors = 450USD
*  All Fuel lines/ pressure accumulator purge = 3hours
*  New FP regulator
*  Fuel tank drain and clean
*  remove and clean Control Pressure regulator = most wrenches won't, just
R&R
*  3 Fuel filters in 1000 miles

Sound expensive?  Guarantee, and a major PITA, I wouldn't want to be at
either end of that repair again.  So, how bout some FP basics to help those
now parnoid, and the naysayers.
*  FP past 100k are on borrowed time
*  FP are cooled by gasoline that is in the tank, no fuel = no cooling.  Good
idea for warm weather folks to keep topped off tank
*  FP work extra hard if the Fuel tank return regulator is clogged or not
functoning correctly.  On CIS cars, this is the 16mm nut on the front of the
FD, careful on R&R there are springs and o-rings in there.  A clogged or
otherwise defective assbly, sends more fuel back to the tank than is being
demanded by the CIS
*  ALL in tank fuel pumps should have the lower screen removed per Audi TSB
covering 1986-1991 5k and 200 model cars, ck archives, I already posted the
procedure.
*  A fuel pump has a baseline noise.  Listen to it.  If it gets louder over
time, there is a problem.  Find it.  The above repair is the risk, time is
the bet.  Best to ante early.
*  As a rule, if you bought a used car, replace the FP, you don't know it,
why risk?
*  Make sure you have good voltage at the pump, many Urq owners have already
found this and relayed under the rear seat.  As with all vw/audi wiring, that
is a pretty small wire that runs almost 16feet from the FPR to the FP.
*  Check system and Control pressure before and after pump R&R
*  R&R of FP should be accompanied by a system and CP ck, as well as a CO
adjustment
*  Save some diagnostic hassle, replace the FPR and the FF with the FP as
baseline

ANYONE who tells you that pump noise is "normal", isn't betting anything but
the keyboard he's correct.  Most of the symptoms that have come to my
attention is a recognition by the owner (some who wouldn't even know how to
change oil), that this is a new or increased level of noise.  THAT is an
indication that something might not be right.  Without the above baseline
assurances, I wouldn't tell anyone that noise is normal.  For Mr. Flynn,
first make sure your CO is adjusted post install, then ck system and Control
Pressure.

Trust your ears folks.  One that gets louder when it's hot out or under
certain conditions is different from one that is getting progressively
louder.  Also, my understanding is that a later model fuel pump (motorola I
believe) supercedes the Bosch one at the dealer.  This is supposed to be a
"better" pump design.  Also about twice the price of the good ol Bosch unit.

HTH
Scott
QSHIPQ@aol.com
'87 5ktqwRS2
'87 5ktq
'86 5ktqw
'84 Urq