HC levels on emissions test.... PASSED, good ole Metro Nashville Options

[malcolm2]

'75 1911 L-Jet with about 7000 miles on it, and a fresh oil change this week. Fresh injectors before the first test. Probably running 87 oct E10 gas today. Might have been 93 100% last year.

12 months ago I passed the state county sniff test here are the results from 10/2013:
HC 399 limit 500
CO 0.65 limit 5.0
CO2 11 no limit listed

and from just moments ago 10/2014:
HC 428 limit 500
CO 3.83 limit 5.0
CO2 11.53 no limit listed

2 different inspection stations, not sure if that matters.

The CO seems to have jumped. I did tweek a few teeth on the AFM between the tests. IIRC I have moved it 9 teeth.

Plus the HC is getting close to the limit. I can't remember the RPMs during either test, but they tend to be about 1000, a bit high.

It passed but I want to be pro-active, any thoughts about the CO jump and pulling the HC down for next year?

Clark

[GregAmy]

Interesting you have to go through emissions...even the Socialist State of Connecticut exempts everything older than 20 years...

I had a Nissan with an imported Japanese market high-compression, variable-valve-timing engine in it, and I was able to get the thing through emissions every two years. We do a rolling-road test here, not an idle test, somewhere around 3000 RPM. To pass the test, I'd back the base ignition timing 7 degrees to lower the NOX, and I'd add two gallons of denatured alcohol into the 10 gallon tank (with top off) to get the HC down. Passed with flying colors.

On the other hand, these tests are so inconsistent year-to-year and station-to-station that I'd not even worry about it if you're below the limits. I don't see anything that makes me worry about a latent problem.

GA