I have a 1989 Jeep Wrangler with a 6 cylinder engine. It has a carburator. I failed my smog test.
At 15mph and 1585rpm the NO was 2004 and failed as a gross polluter, but at 25mph and 2426rpm the NO measured 614 and passed. It seems to me that if the technician had run the higher rpm at 15mph I might have passed. What do you think?
Answer:
You want to check the EGR valve system as well as the CO levels. A faulty
EGR valve will cause high NO, and can cause low CO emissions.
posted by SmogTips Support
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