Please help - Emission test badly failed - 88 90Q

[InfernoCL]

For these cars, always start at the oxygen sensor, then diagnose as you see
fit.

-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com] On
Behalf Of V. Jokic (via Sympatico)
Sent: Saturday, March 01, 2003 10:17 PM
To: quattro at audifans.com
Subject: Please help - Emission test badly failed - 88 90Q

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I am new to the list... I failed (Ontario) emission test with my 88 90Q
(5cyl, 10v), and the results were classified  (by the  testing  facility) as
"extremely bad".

They even refused to work on it and  give me a "conditional pass" once I
spend $450 on the emission related repairs, since they said they knew
nothing about Audis... Ironically, local Audi dealer (nor any local shop
specialized in European   imports), here in Niagara area, are not certified
by the government to do official  emission related repairs...

Since on a quattro  they can do only a two-speed idle test and measure only
CO and HC ppm, here are the results:

Idle (808 RPM):
CO% : allowed 1%,   measured 9.31%
HCppm: allowed 200,   measured 542

2500 RPM:
CO% : allowed 1%,   measured 4.52%
HCppm: allowed 200,   measured 232

Could anyone five me some idea what might be wrong?

Re CO, I suppose,  I should adjust the mixture, but I am unsure where the
mixture adjustment screw is located on an 88 90Q 5 cyl 10v engine (nor I
have a Bentley manual...). Could someone give me dome hint?

Re HC, I am even unsure where to start from - perhaps oxygen sensor?

Also, does someone know what  the exact purpose of that screw on the top of
throttle (that works as the throttle stop) is? Can it have any influence on
the CO and/or HC  content? I did play with it  one time in the past, and
managed to improve idle stabilization process, at that time, when a  the
throttle would be released, the RPM would dip down to 400 and then bounce
back to about 800, but after turning that throttle stop screw
anti-clockwise, the RPM now  quickly drops to about 1200 and then usually
goes slowly down to 800.

Any help would be greatly appreciated.

Regards,

Joe

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