Mechanics

NISSSAN NOX FAILURE MASSACHUSETTS

1993 Nissan Altima

My nissan altima has failed the nox part of the emssions test (limit 2.50 - mine 3.21) I've changed the bpt valve, vacuum solenoid controller and oxygen sensor. The car runs great - no codes - whole exhaust system two years old.
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Dianemarie
May 19, 2007.




If you failed the nox you may just be running lean. Check for change your oil, check for vaccum leaks; especially around the EGR, which is usually the problem. Also change your spark plugs and wires to be safe. If none of that works you may have to retard your timing a little bit and some people even like to dump in a bottle of octane booster before the test, which does often work to lower the nox reading, but not always

Tiny
KaMo
May 20, 2007.


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