CO emmission still quite high - despite new type approved Underfloor CAT

[sean135]

hi folks.

my car failed its MOT on CO emmissions. Mine is a 1.6 16V SE - vw bora - 2000 plate - eng code AZD.
I got kwik fit to re- replace the old shoddy one that they put in , with a type approved one. they did an emissions test thereafter and it sailed through.

the following day, at the MOT retest, after a good slog of the school rat run, it only just passed i,e got 0.199 , with a max CO value of 0.200.
Ive had a EML light onfor about 8 years and in that space of time have replaced about 4 lambda sensors ( my car has 2 CATS and hence 2 lambdas),, the EML light just keeps coming back, so have left it , assuming that the ECU is naff - have heard this is a well documented issue.

My Q is what else could i do in future to keep the CO reading down?
HC i.e hydrocarbons and the Lamdda readings at the MOT retest were all good and sound, so its primarliy at CO issue.

would a high octane fuel prior to the MOT help?
what about an additive or so to squirt in the MAF flap vlave prior?

thx

[belfastmark]

Hi Sean.
It's time to google for terraclean.

Good luck

[zollaf]

a terraclean is not going to put an em light out. there is an underlying fault that needs correctly diagnosing, not just throwing new lambda sensors and cats at it because thats what the computer says.

[belfastmark]

Fair enough Zollaf.
Though terraclean wouldn't do any harm, quite the opposite infact. Worth doing when the EM light problem gets sorted ?

[zollaf]

snake oil.
use some fuel treatment if you want.