Failed MOT - carbon monoxide emmissions too high?
Discussion
Need help on likely causes please.
My 500 pre-serp (all 3 cats still present) has emmissions >1000 instead of <200 suggesting it's running very rich. I have replaced the AFM, lambda's and plugs in the last year and had a RR session to try and find the cause of running rich but to no avail.
Any thoughts as to what to do next please?
My 500 pre-serp (all 3 cats still present) has emmissions >1000 instead of <200 suggesting it's running very rich. I have replaced the AFM, lambda's and plugs in the last year and had a RR session to try and find the cause of running rich but to no avail.
Any thoughts as to what to do next please?
You've not got the story quite right here at a guess.
Carbon monoxide (CO) is measured as a percentage - for the Griff it has to be less than 0.5%
What you seem to be talking about is the hydrocarbons in the exhaust gasses. These should be less than 200 ppm.
My car played this trick last year:
The lambda sensor and the MOT test machine said the mixture was spot on, the CO was a little high (not surprising - I had no cats at all!) but the hydrocarbons were well off. It turned out to be the exhaust valves leaking during combustion - resulting in a top end rebuild.
Carbon monoxide (CO) is measured as a percentage - for the Griff it has to be less than 0.5%
What you seem to be talking about is the hydrocarbons in the exhaust gasses. These should be less than 200 ppm.
My car played this trick last year:
The lambda sensor and the MOT test machine said the mixture was spot on, the CO was a little high (not surprising - I had no cats at all!) but the hydrocarbons were well off. It turned out to be the exhaust valves leaking during combustion - resulting in a top end rebuild.
Edited by dnb on Monday 2nd July 15:56
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