1993 Toyota Corolla Failed Emissions - Check engine light o

1993 TOYOTA COROLLA
245,000 MILES • 4 CYL • 2WD • AUTOMATIC
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93COROLLA
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I have a 93 Corolla - 1.8L. My car failed the emission test. HC read 434 and the CO% was 1.96%. The check engine light is off. What could be the problem?
Aug 3, 2009 at 7:02 PM
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STEVEW84
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anything done to the car recently? Any tune-up? What rpm were those numbers at? Did you let the car run long enough?
Aug 4, 2009 at 7:14 AM
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93COROLLA
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RPM = 3179

Spark plugs and distributor cap (with wires) were done last year. I also had the resonator done last year. The car was running all day. Any advice would be greatly appreciated.

Thanks.
Aug 4, 2009 at 6:51 PM
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STEVEW84
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I'm not sure how long the rpm stayed at that, but I'm pretty sure you have a catalytic converter problem. That HC is way high for that rpm.
Aug 4, 2009 at 7:49 PM
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93COROLLA
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If the problem was the cat, why wouldn't my check engine light come on?

Thanks again.
Aug 4, 2009 at 9:03 PM
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STEVEW84
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its obd1 car that has no cat monitor. OBD2 came out in 96. That is why they had to run the car for emmissions. If it was a 96 and newer they would plug into the OBD2 port and check for codes and make sure the monitors are set.
Aug 4, 2009 at 9:14 PM
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CORMECH
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you might want to check to see if the O2 sensor is operating properly. you will also want to check for any exhaust leaks before the O2 sensor. check the exhaust manifold for cracks as this would allow air into the exhaust system fooling the O2 sensor into thinking that the engine is running lean. hope this helps.
Aug 5, 2009 at 7:28 PM
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