Quote:
Originally Posted by fc227 (fred)  What do not under stand is why is the NOx so much higher than two years ago? When basically nothing has changed. Unless the EGR vacuum line was unplugged. |
If you look at your co readings, you'll notice 2006 is consideraby richer than 2008. A leaner mixture burns hotter (until about 16.2:1) which causes chamber temps to rise and NOx. In case you dont know, NOx is formed when the chamber reaches 2500* and the molecules in air seperate onto N and O. The richer mixture from 2006 cooled the chamber enough to reduce NOx. You need to a) get the EGR valve operating at a volume sufficient for a given airflow, b) richen the mix a tad, 3) use a 3 way catalyst 4) any combination or all of the above.
Jim
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