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Registered
Join Date: Jul 2002
Location: Milton Keynes, UK
Posts: 59
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Emissions results on 3.2
Hi all,
I am in the UK and I just had my car pass its MOT. (Yearly test for safety and emissions). All was well but one thing intrigued me. My car had CO of 1.5% and HC of 74ppm. This is well within the MOT specs so no problem from a legal point of view (UK limits are 3.5% and 1200ppm) but the testing guy pointed out that his chart showed a 3.2 as having an ideal of CO 1.25% +- .25 and HC of 800ppm. Now, I'm not worried (should I be?) but what should the 3.2 emisions be. Maybe his chart is plain wrong? I had a figure of 77ppm last year from a different shop so I thing his tester is probably accurate. Can a low figure for HC be a bad thing? I thought this was essentially a measure of how much fuel is being burnt and therefore the lower the better. This is for a UK 3.2 without a CAT so any US measurments would presumably have to be upstream of the CAT. Cheers Andy |
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08-02-2004, 08:02 AM
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Registered
Join Date: Jul 2002
Location: Milton Keynes, UK
Posts: 59
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One more try...
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08-03-2004, 12:58 AM
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Fuchs w h o r e
Join Date: May 2003
Location: Vancouver, Canada
Posts: 644
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Those numbers are excellent for an engine without a CAT.
The CO is a measure of how you (or the ECM) have adjusted the mixture. The HC is a measure of what your engine does with that mixture. A low HC means your engine is burning the mixture very efficiently. Any engine pushing less than 100ppm of HC without a CAT is doing very well. I can say without doing a leakdown test your valves are sealing extremely well. A lot of people don't realise how valuable an emissions test is as an engine diagnostic. |
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08-03-2004, 01:42 PM
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