high CO

[Jay Negrin <jmnegrin@domain.elided>]

Tess (and anyone else who may be listening in)

The carbon monoxide (CO) level is indicative of incomplete combustion.
Complete burning leaves carbon DIoxide (CO2).  Incomplete combustion
happens when there is a rich condition.  Too much gasoline for the
amount of air in the cylinder.  Richer combustion tends to be somewhat
cooler (this is all relative) than combustion that is balanced, or
slightly lean.  The hotter the combustion, the more oxides of nitrogen
(NOx) are produced.  So, if you have high NOx, due to running lean, you
fail the test for that, but the CO emissions are virtually gone.

That's it for the chemistry.  I'll leave the catalytic converter
operation, and how it related to O2 sensors for someone else.

My Alfetta GT failed smog, due to high CO last time it went in for a
check.  My mechanic leaned out the mixture on the SPICA, so that it
passed.  It all made sense to me, at least, when it was done.

Ciao

Jay Negrin
76 Alfetta GT - Sunny, overcast, warm, and then cool, Southern
California
Season changes can be interesting, even if it is happening WAY to soon
this year

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