Garage Support

Back to Forum

Post a Response

Any - Older vehicles with catalyst MOT question #

Posted by Paul Howd on August 29, 2012, 2:22 pm

Year of Manufacture *: any

In particular this is a 53 plate VW golf TDI, but would apply to any diesel of a similar age.

The cat is noisy, (I havent seen it yet so do not know whether this is a broken up matrix or an actual leak)

But, assuming the former, what is the current MOT position as regards poking the broken matrix out leaving an empty box and then refitting it to the car?

(I understand that even on pre-emission years, if a cat was orriginally fitted it has to be there, but it doesnt have to "Work". Would a poked out box constitute a "non-functional" cat or an "absent" one? even supposing anyone would notice without removing it from the vehicle)

Paul

Re: Any, older vehicles with catlylists MOT question.

Posted by Steve Shaw on August 29, 2012, 8:26 pm, in reply to "Any, older vehicles with catlylists MOT question."
Message modified by board administrator September 4, 2012, 2:14 pm

who would know?
there is no cat testing on diesels at the moment

Re: Any, older vehicles with catlylists MOT question.

Posted by sean savage <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5559' width='330' height='300' border=0 style='border:none;'> on August 30, 2012, 10:15 am, in reply to "Re: Any, older vehicles with catlylists MOT question."
Sean Savage

Steve is correct. they are bringing it into the test that if the cat/dpf is missing on diesels it will fail, but as long as the externals are there we cant fail it. as stated how does the tester know the inners are there or not?

sean

Re: Any, older vehicles with catlylists MOT question.

Posted by aidan birley <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on August 30, 2012, 1:19 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Aidan Birley

hi
I understand that proposed MOT testing of cats will only apply to petrol i.e. vehicles that are required to have a cat emission test.

no plans for diesel cats or DPF's that I am aware of

Aidan

Re: Any, older vehicles with catlylists MOT question.

Posted by Mark Carter <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on August 30, 2012, 3:18 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Mark Carter

From the way I understand it I'm with Aidan.
Petrol only at present.

Mark

Modern cars, Its all wizardry and witchcraft

Re: Any, older vehicles with catlylists MOT question.

Posted by Nick Favell <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3407' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 12:03 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Nicholas Favell

That is correct.

Copied from the manual;

On vehicles that qualify for a full cat emissions test, check the presence of the catalytic converter.

Diesels do not qualify for a full cat test - only a smoke emmissions test.

So a missing DPF or cat is not a reason to fail a diesel car.

Nick

Re: Any, older vehicles with catlylists MOT question.

Posted by Graham McNichol <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2733' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 1:15 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Graham McNichol

So if your car passes a BET test without a cat it doesn't need one because it doesn't qualify for a full cat test.
Graham.

Re: Any, older vehicles with catlylists MOT question.

Posted by aidan birley <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 1:21 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Aidan Birley

graham

Good try !

The BET test is a cat test, so yes ! older / non cat vehicle do not use bet test.

The final rules are not out yet, but expected to be along the lines of cars that are listed for full cat test. This makes sense as there is a definitive list of vehicles to apply the standard to.

cheers Aidan

Re: Any, older vehicles with catlylists MOT question.

Posted by Graham McNichol <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT2733' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 3:34 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Graham McNichol

Just been devils advocate,
It clearly states in the method of inspection (7.1) that we check for cat presence on vehicles that are subject to a 'full cat test', is a basic emmissions test a full cat test or is it something we do after a BET has failed.

Graham.

Re: Any, older vehicles with catlylists MOT question.

Posted by Mark Carter <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 7:51 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Mark Carter

>>> check for cat presence on vehicles that are subject to a 'full cat test', is a basic emissions test a full cat test or is it something we do after a BET has failed.<<<

The way I see it is as follows, The important words in the above are "subject to"

All petrol vehicles (after 92) are "subject to" a full cat test should they fail a BET test.

No diesel is subject to a "full cat test"

Therefore the "presence test" is only for petrol vehicles.

I'm quite happy to be corrected and learn along the way.

Mark

Modern cars, Its all wizardry and witchcraft

Re: Any, older vehicles with catlylists MOT question.

Posted by Andrew West <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5350' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 9:02 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Andrew West

How about a petrol vehicle converted to run on lpg/ I know of several that the cats have been replaced with straight pipes. As I interpret it the lpg converted vehicle is not subject to a full cat test, but others may think differently.
Regards, Andrew

Re: Any, older vehicles with catlylists MOT question.

Posted by Mark Carter <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 4, 2012, 10:23 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Mark Carter

As far as I remember the book tells you to test as presented and issue a pass/fail accordingly.

Mark

Modern cars, Its all wizardry and witchcraft

Re: Any, older vehicles with catlylists MOT question.

Posted by Ed Kaps <iframe src='https://members4.boardhost.com/ukautotalk/info/user=UKAT5536' width='330' height='300' border=0 style='border:none;'> on September 5, 2012, 3:18 pm, in reply to "Re: Any, older vehicles with catlylists MOT question."
Edward Kaps

This is just about as clear as rules that the Motor Sports Association (MSA) brought in last year. I do some scrutineering and we were told that all competition vehicles had to be fitted with a cat when being scrutineered,--No test of exhaust gas,-no check to see if the internals were there,-If it looks like a cat then it must be a cat,-what a joke.

Ed Kaps

Re: Any, older vehicles with catlylists MOT question.

Posted by Nick Favell <iframe src='https://members4.boardhost.com/ukautotalk/info/user=ukat3407' width='330' height='300' border=0 style='border:none;'> on September 11, 2012, 8:54 am, in reply to "Re: Any, older vehicles with catlylists MOT question."
Nicholas Favell

With a few exceptions, any petrol car registered after 1st August 1992 (ie K reg) will require a full catalyst test, so will need a catalytic converter to be fitted.

If a car passes a BET test on the MOT we can safely assume that the cat - or what looks like a cat - is working.

Only if it fails the BET test do we continue on to do the full cat test. The full test includes measuring the engine oil temp to ensure that the engine is up to full operating temperature, and allow a longer warm up period for the cat.

Don't let's forget that the BET test is done to tighter limits than the full cat test. If we could all run cars without cats and still get below 0.2co and a lamda of 1 readings I think a lot more people would.

But to confirm that diesels do not require cats to be fitted for the MOT test

Nick

« Back to index

[ Garage Support ]

Copyright © uk autotalk