Hi,

I have a 1998 STI import.
The Exhaust is decat with 3inch pipe from manifold end to back box.

It's failing the MoT on CO emissions caused by what I presume to be the decat exhaust.
From reading various threads on here it seems most people have to resort to fitting a standard exhaust for the MoT. However, in the majority of cases I have noticed the CO readings are far higher than mine.

Limit is 0.2%. Mine is reading 0.7%.
Prior to this reading it also failed with the Lambda, however I fitted a new one and all was fine apart from CO.

Only thing that I have thought of trying is fuel cleaner followed by a good blast but obviously don't want to do this unless there is a pretty good chance it will work (otherwise will need to fork out for another failed MoT).

Can anyone recommend anything other than having to change the exhaust?

Many thanks,
Ben

 

if lambda is passing then the issue is lack of cat not removing the CO.

is HC passing?

Is it the fast or the slow idle (natural) thats failing?

Simon

 

You should get a free re-test if its within 14days?

 

find a frendly mot station !

 

Either fit a cat or find a friendly place, do you mean 3" from turbo?

 

Thanks for your responses.

Sorry, I meant 3inch from turbo.
Re friendly MoT centre - not a clue how to (for obvious reasons) find one of them.
I do have 10days if it fails but have no backup plan.

Cheers

 

Without a cat mine passes everything apart from the fast idle, with co around 0.7%.

Decat is a pain, but e.g revolution do a 3" sports cat dp, which should pass the MOT.

 

crikey I thought cars prior to 1999 didnt need cats...how stupid am I...

 

Try '93

JohnD

 

Henrik, thanks for the info. Is this the one you mean?
http://www.just-subaru.com/my93-00-r...t-72108-0.html
Bit pricey but appreciate the advice.

Jolly Green Monster, sorry for not replying sooner.
All emissions pass apart from CO.
MoT tester didn't progress on to the Fast Idle test as 0.7% was reading at Idle.

 

Can get a new cat http://www.carparts4less.co.uk/cp4l/...20a2854&000059

 

good man, thanks for the link.
i don't suppose you know what diameter that is?
am guessing it is the standard 2.5inch?
cheers

 

Yes more than likely I didn't think about the 3"