MOT emissions failure

Berne Leigh

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Mar 4, 2019
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Today my 2008 Golf Match 1.9 TDI failed its MOT on emissions.

The test result gave a mean value of 1.31 [m-1]. But the plate limit on the sticker near the passenger door has a 1.00 in a box and the garage has taken that as the target.

The last 2 years the results have been 1.73 and 1.44 but these have been assessed against a target of 3.0 and hence has always passed.

So I have the following questions.

Is the 1.0 in the square the right number. It has been suggested that because the car is so old that it is not correct to use this number?


It has only been suggested that if the manufacturers plate was not there or not legible then the car would be tested against the default target of 3.0 for a pre 2008 turbo diesel. Surely it is not as simple as removing the plate?

So if the target is right and cannot be avoided what can I do to get the car through the test? The car has historically been used for pottering around but recently drove to Austria so it has had a good run.

I am planning to try Cataclean but what else can be done? I have hear stories of 2 stroke oil?


The car has been recently serviced but could it be a sensor?

I am concerned that if the garage gets hold of it there could be lots of expense with new catalytic converters etc.

Any advice or information gratefully received.

Sam
 

Gazwould

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Try having a 2003 1.9tdi VW with 0.60 VIN stick manufacturers smoke coefficient value !

All very possible , 2 Stroke oil....
 

Pete1

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Friend of mine rocked up in her 2002 Mk4 Golf 1.9 SDI which has a 0.4 figure on the plate; she was worried about ABS light, possible broken front spring and missing engine undertray prior to MOT this month. That smoke figure was my main concern and I advised making it illegible.

The MOT test manual is freely available here: https://www.mot-testing.service.gov.uk/documents/manuals/class3457/
Section 8.2.2 covers diesel engine smoke testing. Refer there for exact wording regarding plate smoke value etc. It strikes me as being a bit vague, and doesn't exactly lead the tester by the hand. I don't know if that document is 'the law' regarding MOT but if it isn't, I'm not sure what is. I can't see reference to illegible/obscured smoke values, which I thought I had seen somewhere - "if it can be found" or words to that effect. Dunno where that was.
 

Pete1

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Drive at high revs in a lower gear than usual for at least half an hour on the way to retest. Try to keep the revs continually high even though you'll be sorely tempted to change gear.
 

Pete1

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Keith, if you look at the title of section 8.2, it is "Exhaust emissions", so yes, diesels do have an emissions test, it's just that the only emission tested is smoke.
 

Keithuk

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8.2.2 Compression ignition engine emissions

8.2.2.1 Exhaust emission control equipment

You only need to check components that are visible and identifiable, such as diesel oxidation catalysts, diesel particulate filters, exhaust gas recirculation valves and selective catalytic reduction valves.

If a diesel particulate filter has clearly been cut open and rewelded, you should reject it unless the vehicle presenter can show evidence that there was a valid reason to cut it open, such as for filter cleaning

Refers to DPF if its been removed not smoke.
 

Keithuk

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Smoke opacity which measures smoke density using an approved smoke meter.

Its not an easy topic to discuss on a forum.

As I asked read the details on the MOT failure.
 
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