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Honda Civic 1997 failed smog check after CAT & O2 sensors replaced.

Emissions Test failed after CAT & O2 sensors (2) replaced. 1997 Honda Civic HX (190K miles) Car failed the Functional Check portion of the Smog Check. Sensor Monitors Incomplete. The repair shop replaced the CAT and both O2 sensors and the Sensor monitors tested complete except the CAT monitor. But the shop said that one incomplete should not cause the Smog Check to fail. The 2nd Smog check failed the Emissions portions by having High NO gas levels 15MPH:118 to 946 and 25MPH:104 to 882. Did I get a bad replacement part? Thanks
Answer:

Your smog technician is correct in terms of being able to pass the smog check with one incomplete monitor, so long as that monitor is not the Catalytic Converter. As far as the NOx emission failure... we can only suggest conducting a fuel feedback test in order to ensure the ECU is in proper fuel control. A feedback test can be conducted in a few different ways. The idea is to disrupt the air/fuel ratio by adding fuel (usually in the form of propane) to the air/fuel mixture and monitor the oxygen sensor voltage output to reflect the increase in fuel. This is step one. Step two involves ensuring the ECU receives the oxygen sensor signals and adjusts fuel delivery accordingly. posted by SmogTips Support

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