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General => The garage => Topic started by: Mew on 03 February 2009, 15:19

Title: MOT failure - emissions
Post by: Mew on 03 February 2009, 15:19

Just got the Skoda back from it's mot and it has failed on the following:

rear (exhaust insecure) exhaust has a major leak of exhaust gases
co content at idle excessive
co content after 2nd fast idle excessive
hydrocarbon content after 2nd fast idle excessive
lambda reading after 2nd fast idle outside specified limits


Where would be the best place to start? I have absolutely no experience when it comes to cars with cats. I'm guessing the rear silencer issue won't cause the other problems :undecided:

The car is a 95 1.3 spi skoda felicia. I know it isn't a golf, but i assume the principles will be the same with regards to emissions.

Cheers

Title: Re: MOT failure - emissions
Post by: Mew on 03 February 2009, 16:15

So far i have found that the plugs are knackered. Also still waiting to hear from the garage, as they didn't supply the read out for the emissions test so i have no idea how far out it was.

Title: Re: MOT failure - emissions
Post by: Mew on 03 February 2009, 18:10

Right, apparently the exhaust leak was really screwing up the readings, so the guy couldn't take any, yet based on what he got (:huh:) he doesn't think that sorting out the leak will bring it within the limits.

Title: Re: MOT failure - emissions
Post by: JC on 03 February 2009, 19:47

ben, I think you might need a phone number off me  :wink:

Title: Re: MOT failure - emissions
Post by: jettagolf on 03 February 2009, 20:08

fix the exhaust put a full bottle of bottle of injector cleaner/fuel additive(redex etc) in to your tank with about quarter a tank of fuel then hammer the absoulte tits out it to the mot station that should fix it :laugh: i have done this a few times and it would supprise you how it helps

Title: Re: MOT failure - emissions
Post by: Mew on 03 February 2009, 21:31

I've been doing a little research, and it appears i should have gone for a proper thrash before hand the get the engine and cat up to temp.

At the moment i am thinking change the plugs, change the oil and filter, sort the exhaust, test the lambda probe and try some of this cleaner stuff. Beyond that it could get pricey :cry:

Title: Re: MOT failure - emissions
Post by: AudiA8Quattro on 03 February 2009, 21:43

Try using cataclean, in my opinion better than redex. The difference is its designed, unlike redex, to be run with only a small amount of fuel in the tank. It really brings the emissions down!
As for the major exhaust leak, you would be surprised how much that would actually affect the readings.

Title: Re: MOT failure - emissions
Post by: danny_p on 04 February 2009, 09:30

cure the leack first,   old fabia mpi  would hardly run with a blown manifold / cat gasket

Title: Re: MOT failure - emissions
Post by: Mrpug on 05 February 2009, 05:10

A year ago, I had alot of the same problems. Timing,o2 mixture, cat, And o2 sensor. At low speed idle mine fail badly also. Well, come to find out the cat was hollowed out. The o2 was toooo high well over the limit. Good luck lad. the car Gods are with you :wink:

Title: Re: MOT failure - emissions
Post by: Mew on 10 February 2009, 14:24

Passed retest after patching up the hole, oil change, new plugs, tank of 99 tesco stuff and some "emissions reducer".

Not sure what did it, but it needed them all anyway (apart from the emissions reducer stuff)

:smiley: