Lber657

My S2k has always been close to the red liine during the emission check. I use a bottle or two of cataclean during the month before the mot.
It has always scraped through by the skin of her teeth.

Is there any adjustment that can be made to lower the HC reading for the MOT?
I do have a tegiwa free flow cat, i'm guessing that i need a proper cat for the job sadly!

Nottm_S2

What did it fail on?

Your O2 sensors might be done, you can do your plugs and filter and with a hi flow cat get it red hot before the test

I had loads of pain getting mine through last year but it's boosted. High flow cat. I cleaned injectors, new seals and plugs

Lber657

I was thinking the O2 sensor as everything else is new.

noodels

Always put oem cat back on for MOT to avoid this issue,have wideband and Berk HFC apart from these all standard

BenRNBP

Didn't get an emissions print out from my MOT yesterday (passed - no advisories), but it's always been spot on Lambda and well below all other limits (see link to print below). I have a fairly old Berk cat, SAI delete, K&N FIPK but where I think I've done the good work is clean injectors (DIY ultrasonic clean, new baskets, seals and cushions), spot on valve clearances and a nice clean, freely moving IACV. I did replace the MAP sensor and O-ring too, it was a while ago but the O-rings do get flattened/stiff so that's a cheap replacement you can do.

Might be worth looking at your long/short term fuel trims to see if the ECU is pulling/adding fuel due to one or more injectors with a different flow rate due to a blockage or leak.

Oh, and Esso Synergy Supreme+ 99 fuel only..

https://www.s2ki.com/forums/uk-irela.../#post24852946

Nottm_S2

High HC is unburnt fuel - running rich

Was it idle or fast idle or both?

If running rich just an idle it's one of the O2 sensors.. if both there may be something else but ultimately still running rich

You can see my method here for last year's fail (last page)

https://www.s2ki.com/forums/uk-irela...161318/page36/

But I have a wideband and can see the lambda effectively (AFR) on that gauge. Once warmed it should be 14.5.. mine idles a bit richer than that as it doesn't like spinning the SC

flanders

Just get the cat really hot before running the tests and it shouldn't be a problem.
It' much less effective than the stock one so needs a few 9k runs to do a proper job

noodels

I no like some twat to rev the tits out of my £6k engine,it hurts me

Scigheras

If having to go street racing during working hours in a congested metropolitan area doesn't sound too appealing to you, but still want to have a high flow cat, get one of the sport cats from the JDM brands, they are super clean as they have to be certified to pass the japanese emission checks

noodels

Passed,now to remove rattly oem cat and refit HFC