[s-cars] Stange issue - Fuel Pump?

[Vincent Frégeac]

AFAIK, fuel pump problem will appears at high rpm first, or i twill simply
fail with no warning. I tested the pressure on my old one (original
200Kmiles!) and, while the pressure becomes weak when I rev the engine, the
pressure will jump almost instantly to spec when I turn the ignition on.
Even when I break open the fuel line, i twill take a few seconds max to
build the pressure.

I would rather suspect humidity in ignition. That's a typical broken
insulation on spark wire symptoms on other cars. It may mean that you have
some wire pinched in your 1.8T coils set-up and, with humidity, the pinched
wire short circuit with the block so you're running on 4 cyl only.

BTW, have you checked the codes. A fuel pressure low enough to have an
impact at all rpm will raise a code. Running of 4 cyl. Because of ignition
doesn't, sadly, so you have to hunt the problem cyl. by cyl. 




Vincent.

-----Message d'origine-----
De : s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] De la part de James Shackelford
Envoyé : 20 novembre 2007 01:39
À : s-car-list at audifans.com
Objet : [s-cars] Stange issue - Fuel Pump?

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

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