Emissions revisited

Phil Rose pjrose at frontiernet.net
Fri Dec 12 07:51:59 EST 2003

I recall a recent discussion--I think on the V8 list--concerning the 
functioning of the throttle damper (I think that's the term for the 
pneumatic plunger device that prevents the throttle from closing too 
rapidly when released). This damper is intended to prevent excessive 
emissions occurring just as the throttle closes shut (comes to idle 
position). Is that damper adjusted/functioning properly in your car? 
It's the little plunger that contacts the throttle lever shortly 
before it comes to the "rest" position. I believe the Bentley has a 
test procedure for the operation.


At 11:12 PM -0500 12/11/03, Paul Luevano wrote:
>Hi all-
>Looking for some help.  My 200 failed Mass. emissions again.  :(  I'm guess
>there is something "wrong" since this seems to be a reoccurring issue.
>Apologies for the long post.
>Here is my original post from 2 years ago, to save making this even longer a
>And then a follow-up:
>It eventually passed, but I don't know what the final numbers were, 
>I think they
>just wanted to get rid of me, which was ok with me.
>I think there is something definitely wrong with the car, just need to figure
>out what. At 2500rpm, everything is ducky.  Its just at idle where the problem
>is.  The car is obviously running rich at idle.
>Here are the numbers (2001 test and 2003 test):
>Pollutant       Reading ('01)   Reading ('03)   Limit
>---------       -------------   ------------    -----
>HC PPM Idle     393             308             220	<---FAIL    
>HC PPM 2500     105             82              220
>CO% Idle        0.61            0.63            1.2
>CO% 2500        0.60            0.73            1.2
>For the test this year I was running a mix of 1:3 gas:dry gas.  Car 
>now has 170K
>miles on it.
>Now, any suggestions on reducing HC's at idle?  I've been told that there is a
>potentiometer in the MAF sensor that controls the idle mixture.  Anyone know
>about it and how to adjust it?
>I fear that this might be a result of my Stebro "High Performance" 
>cats.  But I
>really feel that this car should pass emissions even without cats.
>Any suggestion and advice welcomed!  I'm heading to a friends shop who has
>access to a 5 gas analyzer, so any advice before that would be great!
>Also wondering if anything like this might help:
>I'm usually VERY cautious of these types of things, and would rather find the
>root problem, but I also want to get my car past the test!  The 
>example emission
>test provided on that site are pretty impressive.
>Paul Luevano            |   AMA * MSF   |'99 CBR 600F4  (Racebike)
>http://teamdaemon.com   | USM * CCS #898|'97 CBR 1100XX (Streetbike)     
>Waltham, MA USA         |  NMA #116657  |'91 200TQ20V   (Winter)
>_____"The purpose of man is to live, not to exist."-Jack London_____
>200q20v mailing list
>200q20v at audifans.com


Phil Rose
Rochester, NY
mailto:pjrose at frontiernet.net

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