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high emissions failed nct :(

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Joined: Thu Nov 06, 2014 9:11 pm

high emissions failed nct :(

Postby r32bob » Thu Nov 06, 2014 10:07 pm

hi there my altezza failed the other day on outrageously hig emissions on both low and high
here are the readings ENGINE OIL TEMP 89 low idle CO10.74 % HC 754PPM


have the lambda sensor changed and NCT again on next Wednesday but any ideas and suggestions as to why the readings are so high would greatly be appreciated

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Re: high emissions failed nct :(

Postby Tosh21 » Fri Nov 07, 2014 1:16 pm

I may be wrong but doesn't a high lambda mean you have a leak in the exhaust system?

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Re: high emissions failed nct :(

Postby Ciaranfox09 » Sat Nov 08, 2014 2:59 pm

No an exhaust leak would cause a lambda reading of over 1.0 as if the car was running very lean meaning air was getting into the pipe and throwing the reading off.

With a lambda of 0.75 the car is running too rich which is clear to see from the high HC reading meaning alot of unburnt fuel in the exhaust gas and the high co reading.

You need to find out why the car is running rich if the car is mapped or has some sort of air fuel controller the settings could be out, If not i would check the MAF and temperature sensors it possible the ecu could think the car is cold when its not causing the overfueling.

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