2001 Hyundai Accent Smog test failed

2001 HYUNDAI ACCENT
83,000 MILES • 4 CYL • 2WD • AUTOMATIC
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ACKPACKET
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I have a 2001 hyundai accent with 83,000 miles. Just took it in for smog and it didn't pass. The NOX was in the high 600's, around 670-680, for both 15mph and 25mph. It failed the NOx at 15mph, and the CO, while passing, is far above average. Sparkplugs are over a year old.
Sep 12, 2008 at 9:43 PM
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RASMATAZ
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NOX failures are usually EGR-related, since the EGR system is primarily responsible for reducing oxides of nitrogen. But NOX emissions can also be caused by a bad three-way converter or a computer control system that remains in open loop.

High CO On newer vehicles with electronic carburetors or fuel injection, the system may not be going into closed loop because of a bad coolant or oxygen sensor. Rich mixture
Sep 13, 2008 at 6:13 AM