Karl

        Here’s My .5cent >

                General Rules of Emission Analysis

        • If CO goes up, O2 goes down, and conversely if O2 goes up, CO goes down. 
           Remember, CO readings are an indicator of a rich running engine 
           and O2 readings are an indicator of a lean running engine.

        • If HC increases as a result of a lean misfire, O2 will also increase

        • CO2 will decrease in any of the above cases because of an air/fuel imbalance or misfire

        • An increase in CO does not necessarily mean there will be an increase in HC. 
           Additional HC will only be created at the point where rich misfire begins (3% to 4% CO)

        • High HC, low CO, and high O2 at same time indicates a misfire due to lean or EGR diluted mixture

        • High HC, high CO, and high O2 at same time indicates a misfire due to excessively rich mixture.

        • High HC, Normal to marginally low CO, high O2, indicates a misfire due to a mechanical engine problem
           or ignition misfire

        • Normal to marginally high HC, Normal to marginally low CO, and high O2 indicates a misfire due to
           false air or marginally lean mixture

                From here

http://www.crypton.co.za/Tto%20know/Emissions/exhaust%20emissions.html

http://ricksfreeautorepairadvice.com/fix-high-hc-and-failed-emissions-test/

https://www.smogtips.com/failed-high-hydrocarbons-HC.cfm

http://www.auto-repair-help.com/auto_diagnostics/diagnose_emission_test_failure.php

https://www.youtube.com/watch?v=4st6Hf5-nJ4 <https://www.youtube.com/watch?v=4st6Hf5-nJ4>

> On 31 May , 2023, at 5:38 PM, Karl Ploessl <karl.ploessl@GMAIL.COM> wrote:
> 
> I was driving about 10 miles to DMV and was waiting in line ~ 30 minutes
> with engine idling.
> -----
> 
> Karl '81 Westy "Jenny"
> 
> '91 Westy "Jenny 2" Wilmington, DE
> 
> On Wed, May 31, 2023 at 7:29 PM Eric Caron <ericcaron96@comcast.net> wrote:
> 
>> Wow!
>> 
>> This will be an interesting conversation.
>> 
>> Only thing I’ve heard of is it helps to get tested when engine is well
>> heated up.  Also, basic tune up might help.  But, I look forward to better
>> thoughts.
>> 
>> Eric
>> 
>> 
>>> On May 31, 2023, at 5:41 PM, Karl Ploessl <karl.ploessl@GMAIL.COM>
>> wrote:
>>> 
>>> here are the numbers:
>>> 
>>> low high
>>> 
>>> HC (ppm)
>>> 
>>> readings 145 88
>>> 
>>> limit 220 220
>>> 
>>> result PASS PASS
>>> 
>>> 
>>> CO (%)
>>> 
>>> readings 3.39 2.48
>>> 
>>> limit 1.20 1.20
>>> 
>>> result FAIL FAIL
>>> 
>>> 
>>> CO (%) + CO2 (%)
>>> 
>>> readings7.49 13.24
>>> 
>>> 
>>> RPM reading
>>> 
>>> readings 935 2580
>>> 
>>> limit 500 2200
>>> 
>>> result PASS PASS
>>> 
>>> 
>>> The alignments of the table is somewhat screwed up but it failed CO
>>> emission at low and at high RPMs (935 and 2580). What would be the
>> reason?
>>> 
>>> 
>>> Karl '81 Westy "Jenny"
>>> 
>>> '91 Westy "Jenny 2" Wilmington, DE
>> 
>>