[s-cars] 1.8T coil odd behavior

[djdawson2 at aol.com]

That too is interesting.  I have also wondered what role the 1.8 coil pack could play in the actual ignition timing.  I am running Hap's old ignition chip, which was designed around a larger chamber volume in the cylinder head.  Since my head is stock, and I'm not running a thick headgasket, I often got significant detonation in 2nd gear at high boost levels.  However, since the swap, the detonation is gone.  So, I'm left thinking that either the coil packs play some role in the timing equation, or my old stuff was just really bad.
 
Almost seems like it would be interesting to do a before and after timing curve map.
 
Dave
 
-----Original Message-----
From: calvinlc at earthlink.net
To: djdawson2 at aol.com; s-car-list at audifans.com
Sent: Wed, 31 May 2006 23:04:11 -0600
Subject: RE: [s-cars] 1.8T coil odd behavior


Dave,

This is extremely interesting.  The reason I say this is because what you
describe is EXACTLY the same behavior I was having on my 2.7T A6 and a
couple of friends were having on their 2.7Ts as well.  In doing some
research on Audiworld I found a few people who had the same behavior and one
gentleman had a good result by getting the ECU re-flashed with a firmware
update at the dealer.  After much consternation and suggestions from the
stealer that I use LOWER OCTANE fuel I finally got them to re-flash my A6
with an update and the problem went away.

The reason I mention this is because my guess is that the coils on the 2.7
are probably not too far from those on the 1.8's.  I wonder if there is
something about the coils needing a longer dwell time or something before
they reach operating temp.  I have no idea what the re-flash from the dealer
changed in my ECU, but my gut tells me that if you can track that down
through some contacts you might be able to figure out what you need to do in
order to fix the problem on your UrS.

I don't think it could be the 02 sensor, since that is not even in the loop
until well after this time period, if I am reading your symptoms right.  I
used to think the problem with my 2.7 was a fuel enrichment problem...but
the coil warm-up idea almost makes more sense because the thermal inertia of
whatever is causing the problem, assuming its related to being cold, has got
to be pretty small to go away within 15/30 seconds.  Good luck!

--Calvin