Exhaust fail on MOT
 

My car went for an mot today. All passed, except the exhaust emissions. I have on the car hayward and scott turbo back exhuast with an 100 cell sports cat and an 4.5" jap canon style back box. It failed on the lambda reading. The man said its because on the back box tail pipe its to big, and its suck little air back in to the exhaust.

I was wondering has anyone had this problem on their car, when it came to mot time?

Any info and help would be appreciated.

Thanks ian.

Was the engine warm pre-test? I've heard 100 cells need a good warm up before testing to allow the cat to perform more effectively? Might be wrong though?! 200 cells usually pass ok from experience.

Yes had this problem last time, mot guy said it was way off, running Ninja 100 cell sports cat

He said just take it for a run, so drove it bout 5 miles quite hard, came back and passed

Yeah I took it for an long run 15 miles to be exact. Still can put my finger on it, last year it passed with the scoobysport back box. The only difference this year is new back box. Had the car check over all is running perfect. Mapping , engine etc.

Can the exhaust tip really be the problem? Im begining to think the mot man is being to strict and fussy.

I doubt it's due to the backbox, probably just the cat wasn't warm enough. Have to say that's part of the reason why a decat is tempting, if you're going to be hit and miss with the emissions anyway then you might as well save the cash but i digress.

Can't see how it's the bloke being strict/fussy, the emissions limits are layed out in black and white. There's no grey middle ground on that one.

Get them to shove the probe right up the backbox, not just clipped on the end.

Its happened to me before, but never a problem when shoved right up! if you get my drift:lol1:

sounds wrong on many levels :Suspiciou

Or right:norty: