Failed MOT on emissions? any ideas

[QuattroFever]

...Oddly enough this years MOT on the S2 the tester said the ABY engine could legitimately be passed on the older test; he spoke to VOSA - told me it was something to do with it being listed as a 2.3 opposed to a 2.2. Aparrently the ADU was listed correctly though

Anyone know anymore about this? Just failed and told him this. The MOT tester is having none of it!

Co. 0.090 - 0.300 swings around alot.
Hc. 180-500 again swings up and down.

[Ross]

Can't remember the exact details, fella was Richard @ Blakes Services in Stroud if you want to search it... he seemed pretty surprised at the time, but was adament that due to some discrepancy with the ABY engine detail, it was correct for him to do a generic emissions test. He tested my RS2 a couple of months later and exected it to be the same, and was then surprised that actually the ADU was listed correctly, maybe something was updated?

[QuattroFever]

just dealt with vosa about this.

apparently in their big book of cars my vehicle and i guess all other s2's are listed as homologation purpose vehicles. interesting! Mine was registered not in the uk then reg'd uk later. They had no details on where it was first reg'd but DVLA will shed some light on that. All very interesting finding the old girls history...anyway.

all vehicles reg'd post 1992 are subject to a right across the board standard BET test and then a CAT test.

the BET test applies first
flat idle co. - 0.3
fast idle 2500-3000rpm co. - 0.2 and Hc - 200
lambda 0.97-1.03

if it fails they go on to do a CAT test...a failure on a BET is no grounds to refuse cert.

CAT test
flat idle -> co. - 0.5
fast idle 2500-3000rpm -> co. 0.3 and Hc. - 200
lambda -> 0.97 - 1.03

if it fails that as well then it is refused cert. looks I have some fettling to do

200cell sport cat and 3" turbo back thought I would be safe, hydrocarbons are killing it really. No smoke and she has excellent compression so....

[Jamo]

Is it mapped correctly though? could be a timing issue causing it, what about fuelling?

IIRC a lean mixture cause high Hydrocarbons

[QuattroFever]

timing is spot on and flat around idle, also fuelling is the same.

Seems to be that it cant hold it very steady. it sort of waves around where it needs to be but doesnt settle anywhere at idle. AFR sways between 13.5 and 15.5. I've tried bringing EGO in to steady it but it cant hold it. Seems to be related to my unsteady idle which i've been chasing for several months.

I've turned everything off that can interfere, removed the IAC, turned the throttle stop in a little and just running an "MOT map" with reduced ignition around idle to steady it, about 10 degrees (was 16) and aiming for a perfect 1.0 lambda all the way up the revs. Im gonna drop it in tomorrow and hope it'll be ok.

[prj]

Try 6-8 deg ignition, target lambda 1.01 and make sure you have injector latency and engine VE dialled in correctly so it does not hunt around, also turn off lambda feedback completely.

[Cymru1]

i was told once by an Mot tester that the regulation states
"engine emissions" post a certain year (1992?).
NOT registered vehicle emissions which is different.

i.e a 2010 Yaris with an old chevy/rover lump would not
be tested but an old 1970's chevette running modern 16v
unit would be tested.

dont know if the above is 100% tho!

tell him your engine blew and your running a 1990
unit.

[20Vcqdriver]

The Cq failed emmisions this year but was thanks to a cheap Lambda off e-bay
Also, as the Cq is 1986 it doesn't need a CAT and passed easily with new Lambda fitted as I think the limit for a 1986 car is about 5-7% Co and 1200 hydrocarbons.

[benntenn67]

Already mentioned, but I swear by cataclean & their other products (Kalimex)

http://www.systemproducts.com/

http://www.kalimex.co.uk/index.html

[rfsteel]

My 95 ABY with 192k failed today on emissions, the best Co they could get was 0.6%.

She also boiled over when they tried to get hotter exhaust gasses, and was also a bit smokey at fast idle.






Thing is, last year the head was skimmed and gasket replaced along with the, plugs, water pump and cambelt being replaced. I've also recently had the Turbo Oil return gasket replace along with fresh oil, and sport cats fitted.

Apart from the recent sport cats, she is standard as they come.

I'm back to the exhaust place this week to see what they can do to hopefully get me through the MOT, but any ideas where to look if there is anything they can do to help ?

[chiefmechanic]

Mot test

My 1993 s4 with an aan engine has passed tha emission test two years in a row and the figures are 0.7. No cats and a Ss exhaust front to back. Only one box in the system. Was told it could be done under older figures because of the engine type.

[Rikki Kitto]

My 95 ABY with 192k failed today on emissions, the best Co they could get was 0.6%.

She also boiled over when they tried to get hotter exhaust gasses, and was also a bit smokey at fast idle.






Thing is, last year the head was skimmed and gasket replaced along with the, plugs, water pump and cambelt being replaced. I've also recently had the Turbo Oil return gasket replace along with fresh oil, and sport cats fitted.

Apart from the recent sport cats, she is standard as they come.

I'm back to the exhaust place this week to see what they can do to hopefully get me through the MOT, but any ideas where to look if there is anything they can do to help ?

Depends how far away from London you are, if you can pop down we can help

[rfsteel]

Depends how far away from London you are, if you can pop down we can help

SW London, Zone 4, so not too far from London. How could you help ?

I've ordered a replacement Bosch Lambda probe as a precaution and will speak to the exhaust fitters tomorrow to see what can be done with the CATS, if anything and if they emission tested her after fitting.

MOT is due this Friday, so looking for all the assistance I can get.

[moggies]

Have a read through this, may confuse things more

https://www.gov.uk/government/publications/in-service-exhaust-emission-standards-for-road-vehicles-18th-edition

[rfsteel]

Have a read through this, may confuse things more

https://www.gov.uk/government/public...s-18th-edition

I see that the ABY engine code is listed in the Annex, which allows a max of 0.5%, but is
only listed under the Couple and not the Estate bodyshells.