Ford Focus 02 plate - Another Emissions test fail question - lferr2002

Can anyone offer any advice car has failed its MOT on high CO emissions The test print out reads 1st Fast Idle Test

CO Fail 0.67% 0.30 max

HC pass 79ppm 200Max

Lambda Pass 1.01 0.97 -1.03

2nd FAst Idle test

CO fail 0.63%

HC pass 33ppm

Lambda pass 1.01

Natural Idle test

CO fail 0.88% 0.5 Max

Prior to this test the engine management light had been on for about 2 months after failing test 1st time around (with similar values) it was taken to a diagnostic auto electrician who reset the management light and reported a fault of misfire on 4. He saw no problems with the sensors and suggested a retest .

Plugs changed, air and oil filter changed, new oil put through and taken for adecent run (8 or so miles) but driven normally as in up through the gears then taken for todays retest and FAIL!! (values as above)

Car regularly does fair bit of miles on medium jouiornetys eg work days between 17 - 65 miles each way and weekends tend to be short journeys of less than a couple of miles.

Mot suggested Ford dealer which obviously will have to be considerd but at £72 to just look at car any suggestions very welcome

Thanks in advance

Ford Focus 02 plate - Another Emissions test fail question - Robin the Technician


I think this is your problem:

'taken for adecent run (8 or so miles) but driven normally'.

Before you take a car like your's (regularly fails on emissions) ALWAYS take it for a good thrash. I always do this on my way to MOT - and I've taken a lot of them - and theres never been any problems. Making the engine work hard helps to clean all the crud out of the system built up by those steady drives. By driving the engine hard the hot gases blow through the exhaust burning off the rubbish built up inside.

It works for me - and you'll see reference to it many times here on this forum. It's called an 'Italian tune up' referring to the way Italian drivers thrash their cars.

Hope this helps

Robin the Technician

Ford Focus 02 plate - Another Emissions test fail question - injection doc

I,m inclined to agree with Robin, the readings suggest iether a lazy oxy sensor or lazy cat, but first a good hard drive, i.e. long steep incline in low gear making it really work hard to burn off the cat !

If you can get access to an infared handheld thermometer , you need to get the car hot & whilst still running point the temp sensor at the front of the cat and the rear neck of the CAT. there should be 50 degree temp difference at least with it being hotter at the rear, if not this would suggest the cat has done its bit !


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