K Series & MOT lambda limit

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john milner
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K Series & MOT lambda limit

The car has just passed the MOT but I noticed something a little odd. Using my car reg the lambda max limit on the test equipment was 1.03 but the official DVSA limit is 1.09. The engine was coming in at around 1.05 so was failing. I had a copy of what it should be so the tester entered all the specific engine details (1.8 VVC engine type RC) and it passed easily. I had the details with me because every year it struggles with lambda and thought it would be a good idea to arm myself with the correct numbers.

https://www.gov.uk/government/publications/in-service-exhaust-emission-standards-for-road-vehicles

Wrightpayne
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Mine is a '98 K self build (pre SVA) and only needs a visual check.

StevehS3
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My 2012 K MOT cert. says a limits of 0.97 and 1.03. I can't see the reference to 1.09. My actual was 1.017. The previous year it only just passed but that as due to a faulty heater in the lambda sensor. 

John Vine
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I can't see the reference to 1.09.

The Caterham list is on pages 23-24 in the DVSA PDF referenced in #1.

Interestingly, all the models listed have 0.95-1.09 except for the VX 2-litre.

At my last MOT, I took along this list for my R400D.  I was glad I did because the tester (or, more accurately, his gas analyzer) insisted on applying an upper limit of 1.03. (I was coming in slightly higher.)  With the help of the list, he was able to select an engine type with the 1.09 limit.

What puzzled me was that, although the tester had input the VIN, the machine was applying an incorrect lambda range.  I'd assumed that it would have been programmed to implement the DVSA values.

JV

john milner
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Exactly my point. Those numbers should be 0.95 and 1.09. Check the link.

john milner
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Same as me the VIN was not pulling up the correct parameters.

John Vine
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Re #6:

Ah, so it's not just me. I think I'll ask DVSA. I'll report back.

JV

Tazio
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The references to the VX, one shows 2.0 efi, the other 2.0i, so what about those on carbs?
StevehS3
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I see now. I also notice that the CO limit should be 0.30 whereas the MOT test report says 0.20 for my K series, so that is wrong too. I wonder which is wrong, the list or the analyser

John Vine
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...what about those on carbs?

Good question. It's not clear to me but I guess it would depend primarily on year of manufacture?  What age would a typical one be?

I wonder which is wrong, the list or the analyser

Another good question.  My money's on the latter, given that DVSA themselves publish the list.

JV

John Vine
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Re #10:

I wonder which is wrong, the list or the analyser

Looking at the relevant pages of the MOT Manual (Section 8: Nuisance), I don't think either is actually "wrong".  It looks as though the 0.2% CO figure is part of the Basic Emissions Test.  If the car fails that, the tester moves on to a more specific test.  There's a very informative flowchart in that section, too.

JV