1992 Toyota Camry High NOx Fail

1992 TOYOTA CAMRY
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BAKERDAVIDW
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  • 2 POSTS
1992 Camry Ct Emission test failed
Car failed for high levels of Nox… about twice allowable
I have 230K miles on it. It has some issues but still runs well.
Question: Is it EGR system or three-way converter?
Check light works, No codes, Runs smooth at idle, and still has decent gas mileage, Low Hc’s and Low Co2’s.
At first his would seem to indicate an EGR problem.( Running too lean) but with out fault codes?
Question: How much reduction of Nox does the converter provide? (If EGR system is working within parameters)
Jan 16, 2007 at 5:24 AM
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RASMATAZ
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Inspect and test the EGR and the cooling system thoroughly. As for the Cat you can test ahead of it and after for conclusion

EGR can give a tech a good curve ball.
Jan 16, 2007 at 6:23 AM
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BAKERDAVIDW
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Thanks.. The car seems to run cold as in no heat...well little heat. thermo?... coolant sensor..no code/
Jan 16, 2007 at 6:29 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
[quote:c83334d346="BakerDavidW"]Thanks.. The car seems to run cold as in no heat...well little heat. thermo?... coolant sensor..no code/[/quote:c83334d346]

Try the 2 for a start- The EGR 's job is to reduce the combustion temperature and preventing excessive oxides of nitrogen
Jan 16, 2007 at 7:02 AM

Suggested Repair

Inspect and test the EGR system and cooling system thoroughly, including the thermostat and coolant temperature sensor given the weak heat. Also compare exhaust readings before and after the catalytic converter.

Conversation Summary

A 1992 Toyota Camry with 230,000 miles failed an emissions test for NOx about twice the limit, with no codes, smooth idle, decent mileage, and low HC and CO. The owner asked whether the EGR or three-way converter was at fault and later noted little cabin heat. The expert advised testing the EGR and cooling system, comparing readings before and after the converter, and starting with the thermostat and coolant sensor because EGR lowers combustion temperature to control NOx.

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