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Showing results for tags 'smog test'.
The great state of California and I once again disagree on how well my engine is running. Its an 82 CJ7 258ci with about 2500 miles since complete rebuild. Hesco MOPAR MPI kit added. And to me it seems to run great. But I failed smog due to high NO. All other tests (including HC and CO) passed. The strange thing is, the last time (two years ago) I passed no problem. Since then I have not made any changes. I did check faults and it was showing a code for the O2 sensor. Since I read that it is a common cause I thought I had my solution. Unfortunately when I went for a re-check it still did not pass. The smog guy asked if I drove the Jeep after replacing the O2 sensor to let the computer adjust operating parameters. But I had only driven it a few mile to the shop for a re-check. How far do I typically need to drive to get things to reset? The O2 sensor fault has not returned. Is there a way to know if the problem is gone without spending the money on another check? Lou