It's always nice to know what was the final outcome to an issue. Thanks for the update.
Michael Agusta > Date: Tue, 1 Mar 2011 00:43:29 -0800 > From: Charles Slayman <[email protected]> > Subject: [alfa] Final Update on '89 Spider CA Smog Test > > Hi, > > I finally passed the bi-annual California Smog Test. Thanks to all who > provided suggestions and inputs. As a recap, I failed initially for high CO > but passed HC and NOx. The data is in the table below. (If it doesn't come > out in email, I will resend in simper text form). > > The tell-tale indicator was that O2 level was at 0%, indicating there was no > more oxygen left to convert CO to CO2. I found a useful article from > Toyota with a graph showing the relationship between CO2, HC, NOx and CO vs > air fuel ratio - www.autoshop101.com/forms/h56.pdf > > The oxygen sensor was new and putting out a variable voltage. So high CO > indicated a rich mixture and could be explained by 1) leaking fuel > injectors, 2) bad temp sensor causing ECU to run rich or 3) Air Flow Meter > out of adjustment. The temp sensor was OK (using Handsome Eric's L-Jet Tune > Up procedures at http://www.hiperformancestore.com/Ljetspider.htm ). I opted > to go after the spring setting on the AFM rather than pull and check the > injectors. By going 7 notches tighter (leaner), I went overboard and FAILED > for high NOx (Table below) the second time. I backed off to 3 notches > tighter (leaner) and PASSED, barely on the third time. I was bumping up > close to max HC at 15mph and max CO at 25mph. I could probably go one more > notch leaner, but NOx is dangerously high at 15mph. > > Here are the results (not sure if this will print properly): > DATE 2/5/2011 2/23/2011 2/28/2011 ODO 222151 222597 222608 > Note Standard > AFM setting 7 notches lean 3 notches lean *15mph Test* ** *FAIL* *FAIL* * > PASS* ** RPM 2801 @15mph 2834 @15mph 2829 @ 15mph <2829@%2015mph> > HC(PPM) max > allowable 124 124 124 avg for passing vehicles 31 31 31 *HC actual* *95* * > 43* *122* ** CO (%) max allowable 0.78% 0.78% 0.78% avg for passing > vehicles 0.10% 0.10% 0.10% *CO actual* *0.78%* *0.05%* *0.69%* ** ** > CO2 (%) *CO2 actual* *14.50%* *15.00%* *14.60%* ** ** > O2 (%) *O2 actual* *0.00%* *0.10%* *0.20%* ** NO(PPM) max allowable > 815 815 815 avg for passing vehicles 237 237 237 *NO actual* *477* *1599* > *729* ** ** ** ** ** ** *25mph Test* ** *FAIL* *FAIL* *PASS* ** RPM 2870 > @25mph 2853 @ 25mph 2847 @ 25mph <2847@25mph> HC(PPM) max allowable 98 98 > 98 avg for passing vehicles 20 20 20 *HC actual* *48* *33* *65* ** CO (%) max > allowable 0.66% 0.66% 0.66% avg for passing vehicles 0.09% 0.09% 0.09% *CO > actual* *0.78%* 0.05% 0.66% CO2 (%) *CO2 actual* *14.50%* > *15.00%* *14.70%* ** ** O2 (%) *O2 actual* *0.00%* *0.10%* > *0.00%* ** NO(PPM) max allowable 754 754 754 avg for passing vehicles 199 > 199 199 *NO actual* *274* *1424* *287* > > > Two final notes: > 1) In theory, the ECU should be able to make the correct air fuel > adjustments with input from the O2 sensor. But in reality, it appears that > the AFM signal sets the fuel metering and the ECU does fine tuning around > the O2 sensor output. If the AFM is too far off, then the fine tuning won't > be within range. Hence, adjustments to the AFM spring are required on an > AFM that has over 200K miles racked up. > > 2) The smog tech knows to pre-heat the catalytic convertor prior to starting > the test. And the two tests were run in 1st and 2nd gear to keep the RPMs > high and the cat hot. So it looks like my cat is nearing the end of its > life. > > Cheers, > Charlie > '89 Spider -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
