53 STI CAT/Emissions issue
 

My 53 STI has just failed the MOT as the CO reading was too high.

I'm told that this is because both CATS have been removed ( this was done by the last owner and I thought that only 1 had been removed)

Will it pass with just 1 CAT, and if so which should I replace?

Thanks

STi only has 2 cats, one in the downpipe and one just after the downpipe.

Have a look a the down pipe too see if it still has the cat on (will have a big lump in the pipe) if so its probably a case of getting the car stinking hot before the test.

If not you need to find an MOT tester who likes to be bought a 6pack of beer as a thank you gesture ;);)

Perhaps either your cat is knacked or the second one has been removed and not mapped to suit. It should pass on only one, if remapped well. There's lots of second hand cat on fleabay.
Phil

It hasn't got any Cats at all, that's the problem. Sorry if I didn't make it clear.

For a proper MOT all the cats it left the factory with need to be in place. It may pass on emissions just with one in the downpipe, but the tester may well want to see them all in place now it's failed.

Sorry my bad. Find a downpipe from a Sti or an wrx (should be the same). It also should pass on just the centre cat (Scoobyworld use this cat only, for remapping). Or the best route go for a Prodrive sports cat and get the car mapped with it on. Either way will be Mot friendly.

Cheers