Ford Focus Mk2 1.8L Petrol - Hc And Co Values Very High From Mot Emission Test

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Sat 30 Mar 2013 17:33
Ford Focus Mk2 1.8L Petrol - Hc And Co Values Very High From Mot Emission Test - starfield

Hi All,

I have just returned from the MOT test centre and my ford focus passed the test. However when I looked closely at the emission test result, I was somewhat shocked. It almost failed and the emission deteriorated during the course of the year. The table below shows the emission over the last few years

Age Year CO HC Lambda Natural Idle Test / CO

3 2010 0 7 1.01 0.01

4 2011 0.01 1 1 0.01

5 2012 0.01 10 1 0.01

6 2013 0.198 165 0.985 0.231

The emission got a lot worse from 2012 to 2013.

Does anybody know what could cause that?

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Tue 2 Apr 2013 17:50
Ford Focus Mk2 1.8L Petrol - Hc And Co Values Very High From Mot Emission Test - BenG

Looks like it's running rich. Has the fuel economy decreased as well?

Possible culprits could be a failed coolant temperature sensor (engine runs cold enrichment all the time) or perhaps the Lambda sensor in the exhaust, which controls fuelling. Not sure if a MAF failure would have a similar effect or not. Maybe worth getting fault codes read in case that helps with identifying the cause?

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Tue 2 Apr 2013 18:04
Ford Focus Mk2 1.8L Petrol - Hc And Co Values Very High From Mot Emission Test - unthrottled

Lambda is within spec (0.97-1.03). Probably just an aged cat.

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