[s-cars] Strange issue - Fuel Pump?

[Tom Green]

Usually someone riding in the back seat is helpful in diagnosing a
fuel pump problem if you don't hear any change in the noise level.

Before diving into the fuel tank, I would check for codes, since high or
low fuel pressure wreaks havoc on the ecu's ability to manage the f/a
ratio, with even a low tank quantity sometimes causing a check engine
(MIL) light to flicker.

I would change the fuel filter and fuel pressure regulator if they  
have the
miles and years many have on them, or if the problem started right after
one was replaced.  That includes a look at the the vacuum and fuel lines
to these parts as well.

A 20% failure rate for fuel pumps around 100K miles creates a lot of  
list
traffic, but that leaves 80% that haven't caused a problem, so don't  
do your
troubleshooting based totally on list traffic.  It is inconvenient to  
change a
fuel pump just any time or place (not a roadside job) so if you have any
symptoms and/or travel to remote areas, a pump replacement might be
advisable in your preventive maintenance plan.

Tom

> Date: Mon, 19 Nov 2007 23:57:25 -0700
> From: "James Shackelford" <93urs4 at rovershack.com>
> Subject: [s-cars] Strange issue - Fuel Pump?
> To: <s-car-list at audifans.com>
> Message-ID: <81294401B1C847A68CD792ECB56327B8 at JamesHP>
> Content-Type: text/plain;	charset="us-ascii"
>
> Hi all,
>
>
>
> My 95.5 S6 Avant has been exhibiting some strange behavior lately,  
> I am
> wondering if it might be the fuel pump getting close to it's last..
>
>
>
> Right after starting up, and only if it's been sitting for 10-15  
> minutes
> (cold, after shopping, etc, but not after just jumping out for a  
> minute)
> there is a span of maybe 20-30 seconds with no power.. The engine  
> won't even
> rev past 3000-3500 (with no power either, no boost or anything),  
> then after
> that 20-30 seconds it's fine.  Thoughts?  I was thinking maybe the  
> fuel
> pressure is taking a while to build or something.  After this  
> period, it's
> fine.  I think I remember someone having the same problem  
> recently.  FYI, if
> I start it and let it run for a couple of minute before taking off,  
> the
> problem doesn't appear...
>
>
>
> Fuel Pump?
>
>
>
> No engine mods except 1.8T coils
>
>
>
> Thanks for your help.
>
>
>
> James Shackelford

>