Emissions Problems

Henry A Harper III hah at alumni.rice.edu
Wed Jun 12 01:24:57 EDT 2002

Hi Tom,

What "minor adjustments" were performed along with the new spark plugs? (5@
$20 list each is $100 right there, for the proper Bosch F5DPOR plugs) There
isn't much to adjust, the computer controls it all...did he ask the
computer if anything was wrong? Did he pull codes with his
VAG1551/equivalent? (or little LED from Radio Shack) It sure sounds like he
doesn't ever want to see you again! Did that look like it was your last
hundred dollars?

High CO, ok HC sounds like lean running to me - somebody correct me if I'm
wrong. Cause of lean running could be vacuum leak (too much air) or clogged
injectors (not enough fuel), compounded by lazy O2 sensor perhaps. Put a
voltmeter on the O2 sensor signal and see if it bounces around (changes
readings) several times per second at idle. That indicates properly
functioning closed-loop operation...slow responses llike every couple
seconds don't give the ECU good enough feedback data to control the mixture
enough to prevent...failed emissions tests.

Are these the same kind of test results that led you to hand $100 to your
mechanic in the first place? From my casual scanning of the web for
emissions topics a year ago, I would gather that a high HC would indicate
rich running or a misfire which might be helped by new plugs; plugs aren't
going to fix a lean problem though...but what do I know. $100 doesn't sound
like much of a boat payment :)

I'm not familiar with the testing protocol there in CT (from cold start,
rolling road, whatever), but this is something that helped me with a failed
high HC from cold catalytic converter (January) here in Boise where you
drive up to the testing van and the guy sticks a sniffer in the exhaust and
counter on a plug wire: before the test, hold rpm at about 3000 for a
minute out of every two or something like that to keep the cat toasty warm.
This was for the CIS-E GTI, worked like a charm; driving towards work and
then idling waiting for the testing guy didn't warm up the cat enough for
it to work well. The Motronic Audi runs very clean even without this step
(given a lively O2 sensor) but is still cleaner (barely measurable by the
specified test equipment) with warm kittys.

Henry Harper
http://www.henry-harper.com hah at alumni.rice.edu
1991 200 quattro, 116k
1988 GTI 16v, 228k

On Tuesday, June 11, 2002 9:54 PM, Bayviewtom at cs.com
[SMTP:Bayviewtom at cs.com] wrote:
> Hi Folks,
> I'm back after a long absence. I live in CT, and am having an awful time
> getting my car passing emissions. I brought the car in a couple weeks
> and failed the test. I took the car to my mechanic, handed him the test
> results, and let him have a go. $100 later, new sparkplugs and some minor
> adjustments, I immediately took the car to be re-tested. It failed again.
> My time to retest without being fined is running out. I phoned my
mechanic to
> tell him the car failed to pass. To my astonishment, he told me he had no
> guess as to what the problem is, and I had better take the car to the
> Audi dealer. Trouble is, I hate the local Audi dealer.
> To those of you who are emissions savvy, here is what passed, and what
> HC: Pass
> CO: Fail
> NO: Pass (barely)
> Catalytic Converter: Pass
> Fuel Cap Seal: Pass
> I guess I'm just shocked that the guy who's been caring for my cars for
> years is sending me off to the dealer. I plan on looking for another
> but any suggestions from the list that could point me in the right
> would be appreciated.
> Tom
> 91 200 20V Q
> 99k Miles! Oh, and she's for sale
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