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Hc And Co Values Very High From Mot Emission Test


starfield
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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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Hi

Coked up oxygen sensors etc

Cooked Catalytic converter

Clogged Injectors

Blocked Air Filter

It could be any of those above,

Was the car serviced before the mot,

Do you take the car for a blast before the mot

Jamie

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Sounds like general gumming up due to normal wear and tear.

Have you thought of giving the car a Terraclean service?

It was used on Wheeler dealers and took an MOT emissions failure back to nearly zero emissions.

It's being rolled out around the country now and Edd China is even endorsing it on TV (planning to give it a go on my car soon).

http://www.terraclean.co.uk/

(i'm not affiliated with the company or anything like that, I just believe it sounds like a great idea and will save a lot of people the fear of failing the emissions section of their M.O.T)

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any idea how warm engine was when tested, if it wasnt up to operating temperature i wouldnt be concerned with the figures.

otherwise..

if not had recent service, give it a once over, even old oil would be enough to effect emissions...would need to renew oil/filters/plugs anyway before trying to find any further fault

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The car had an oil and oil filter change two weeks prior to Mot test

I did not take the car out for a blast before mot as suggested by James_60

The test was done last Thursday at 0800 and the outside temperature was reading -1.

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any idea how warm engine was when tested, if it wasnt up to operating temperature i wouldnt be concerned with the figures.otherwise..if not had recent service, give it a once over, even old oil would be enough to effect emissions...would need to renew oil/filters/plugs anyway before trying to find any further fault

Outside temperature was -1

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outside temp wont have any significant effect on emissions beyond time it takes for engine to reach operating temp.

put another way, engine oil needs to be around 70/80 degs before you can accurately measure exhaust gasses, in order for oil to reach that temp, thermostat needs to be fully open, probably to the point cooling fan cuts in.

its perfectly ok to carry out a test on a cold/warm engine, as exhaust gasses may still pass the emmission test...

if they had failed then next stage would have been to measure the oil temperature untill it reached the recommended min temp for that engine,once reached then gasses are measured again.

so the figures quoted on your car test may have been measured on a relatively cold engine, no further measurements needed as they passed.

only way of knowing if you have a pending problem is either ask if your engine was hot at time of test, or run it up to temperature and get gasses measured again..

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  • 1 year later...

Hi everyone,

My 1999 Focus 1.6 has just failed the MOT on emissions, (it barely scraped through last year) with Co reading after 2nd fast idle test of 0.7 and Hydrocarbons in excess of 300. The Lambda reading was also outside specified limits (sorry I only have the failure notice and not the emissions printout). The car runs great and has a very smooth idle. Mileage per gallon is pretty good at about 26-28mpg on average and much better on a long motorway run. I have renewed the air filter, and done an oil change with the correct synthetic 5w30 oil as part of a full service just a few weeks ago. The car does not smoke but there is a lot of soot in the exhaust tailpipe.

The guy at the garage, whom I have used for years and is trustworthy, said he suspected something sinister such as a leaking valve, worn bores etc etc, but when I removed the spark plugs to check for any mixture/ oil burning issues, the plugs were clean with only light tan/grey deposits, and this is after 12000 odd miles since they were last changed. Like I said, the idle is smooth and there are no hints of a misfire at any speed.

The only thing I can think of is that the "dealer" I got it from 18 months ago had to replace the exhuast after a few days 'cos it was blowing. I now suspect he used a secondhand exhaust and possibly also a second hand Cat. Is it possible that the cat was coked up and the high emissions reading is from deposits within it being burnt by the hot exhaust gasses? as the clean spark plugs don't indicate and bore/valve/mixture issues. MOT runs out on wednesday so any ideas anyone?

Many thanks

Rob

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