Posted this on VVOC as its for my Vec B - but as there are some knowledgable people here - thought I would also post here too :
Ok - so my problem that is driving me bonkers! lol:
Car is a Vec 2001 2.2 150 Sri (z22se of course) as you know..
Basically - I keep getting the eml with: P0420 - Catalyst System Efficiency Below Threshold (Bank 1)
I clear the code and then 10 - 30 or so miles later it will come back.
What has been done so far to recap:
- When I bought the car it had a brand new exhaust from the manifold back - so new cat, mid and rear box. This was producing the code as above
- I changed the rear box for a letterbox irmy exhaust. This was still producing the code - although I didnt expect this to change
- Bearing in mind the cat was brand new - I got two brand new Genuine VX Lambda sensors and fitted them. This was still producing the code as above, no change
- Knowing that the cat was not a genuine VX one and was a aftermarket cheapy one - I got a genuine VX one (all be it second hand) which had the pre cat removed and fitted that. This was still producing the code as above, no change.
- I then fitted a EGR cheater and blank from z22se.. this made a big difference to pickup and idle. But still the same code as above.
So I am now at a loss.. In a nutshell I have done everything I can think of to resolve this yet still its present.
It does seem to come on after a good 'enthusastic' drive, but never straight away - it seems to be after between 10 - 30 miles of the last eml reset.
I do run it on V-Power petrol only, and have never used anything else since I got the car.
So really after some help chaps as this is getting VERY annoying and the car is so nice to drive this lets it down.. MPG seems reasonable and there are no running issues.