A8 Question

Fred Munro munrof at sympatico.ca
Mon Oct 28 22:36:21 EST 2002

Hi Frank;

I don't know how the A8 ignition system is set up, but similar problems on
the UrS direct ignition systems (coil over spark plug) can be caused by a
failing POS (Power Output Stage, not the other meaning for this acronym, but
I'm sure it comes to mind when you find out how much a POS costs!). The UrS
fires 3 plugs off one POS, so it has two. It can also be caused by a bad
coil. The problem can be isolated by disconnecting injectors as the engine
is misfiring - the injector(s) which does not make the engine run worse when
disconnected identifies the bad cylinder(s).
FWIR abrasive blasting is not recommended for plugs - it can result in
failure of the insulator at the plug nose.


Fred Munro
'94 S4

-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
Behalf Of FBFISH at aol.com
Sent: October 28, 2002 10:03 PM
To: quattro at audifans.com
Subject: A8 Question

[ Picked text/plain from multipart/alternative ]
Group- I do not see many posts on A8s, but I thought I would give this a
in case someone has had a similiar problem on a late model Audi. The car has
56K miles on it and recently started running rough at start-up only if left
sitting for an extended lenght of time (week or more). The problem seems to
be worse if it is rainy/damp. The car smothes out fairly quickly and will
fine untill left again to set for several days. This has occured on at least
4 occasions. I have pulled the codes after each event which are always
associated with one bank (cyl 5,6 or 7). VAG COM says I am having
and/or random  miss-firing. I have pulled the plugs and cleaned each with an
abrasive blasting, inspected all the wiring and spark plug boots with no
problems I can visualy detect. With no distribuitor, The only common item
would be fuel, but that does not seem to be related to one bank. Any BTDT,
suggestions on what I am overlooking. BTW, is there an A8 site? TIA
Frank Santoro
1990 V8
1998 A8

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