MOT emissions query

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Thu 21 Aug 2003 21:59
MOT emissions query - smokie
The Omega MV6 went for it's MOT today, and I'm pleased to report it passed.

Comparing the emissions figures with last year, I see that it's taking a turn for the worse (2002 figures in brackets)

Fast Idle Test

CO - 0.18% (0.02%)
HC - 49 ppm (25ppm vol)
Lambda - 1.01 (1.000)

Natural Idle Test

CO - 0.03 (0.01)

Is there anything I can read into this? Imminent catastrophe? Or is it just a "wear and tear" thing? The car had just been on a 90 mile motorway journey immediately prior to being dropped off today, and has covered 19,500 miles since last year.
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Thu 21 Aug 2003 22:57
MOT emissions query - Andrew-T
May be just that the test machine needs recalibrating?
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Fri 22 Aug 2003 08:51
MOT emissions query - Adam Going (Tune-Up)
Nothing to worry about IMHO. Andrew-T could be right, or different atmospheric/temperature conditions can play a part, or possibly simply that they had not fully warmed the car up, or the car has had more short runs just prior to test. Either way, I would't loose too much sleep on this one !

Regards, Adam
Whatever is rightly done, however humble, is noble.
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Fri 22 Aug 2003 10:14
MOT emissions query - SpamCan61 {P}
My 2.5 V6 omega was very close to the emissions limits last year (0.29 on the 0.3 spec for CO) However this year I gave it a thorough Italian tune-up before the MOT; and the CO had dropped to 0.08 on the MOT. As Adam states; more to do with how the car has been driven than a worrying long term trend.
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Fri 22 Aug 2003 10:41
MOT emissions query - Sooty Tailpipes
A few years ago, I had an MOT, passed the emmissions by a long way, went to a garage I kept driving past which said "Free Emissions Tests", the results were as different as yours but still well within the limits, so I would put it down to margins of error, catalyst temp, equipment, fuel etc...

Your Lambda value is good, so I wouldn't worry.
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Fri 22 Aug 2003 10:54
MOT emissions query - Andrew-T
Adam - on a related query, I put my 99T 306 HDi throught the test this week after it had lain idle since the start of July. It had a few vigorous miles before the test and seemed to be running well. It passed easily enough, but I was surprised to find the readings increase from 1.7 to 2.2 during the test - usually they drop as soot is blown out. Any explanations?
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Fri 22 Aug 2003 22:18
MOT emissions query - DL
Variable throttle depressions on behalf of the tester account for this I'll bet...
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Tue 26 Aug 2003 21:12
MOT emissions query - Adam Going (Tune-Up)
Andrew, Sorry for delay in replying - a few days offline does you good !!

No real explanation here. DL could be right. Or perhaps if testing had been continued it would have come down again.

Regards, Adam
Whatever is rightly done, however humble, is noble.
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