M.O.T- TODAY-FAILED EMISSIONS?????

[wayne1.8t]

Hello again
Car failed it's m.o.t for the 1st time today on the emissions the person said it's fine on fast idle test but on the natural idle it failed giving 4.613%CO
And should be 0.500% ???
he told me to put some additives in with the petrol and bring it back in a day or two or clean my throttle body?
Any clues on what this could be any help would be great?

 

[aragorn]

you dont need additives, you need to fix whats broken.

Vagcom scan is your first step. It could be an airleak or similar, or a broken sensor etc.

 

[DJ_Troopa]

I had this last year and this year mate. Last year i had my exhaust system done with 200 cell sports cat and it failed. I put Wynns injector cleaner in, drove about 20 mins down the motorway and back to the MOT station straight away. As soon as i arrived, wacked it on emissions test and it passed!

My MOT man says he sees this alot with petrol Audi's unfortunately. I've had the car checked on vag-com and it's fine. So next time you go for an MOT, before you go, put Wynns injector cleaner in, go for a drive down the motorway doing good constant speeds for about 15-20 mins there and back, go to the MOT station straight away and watch it pass!

 

[aragorn]

It depends how it fails.

You probably find it was just the long drive that did it, rather than the injector cleaner in your case.

In his 4.5% CO is about 20times the allowed figure. Even with no cat fitted at all you'd expect to see around 0.5-0.7% assuming the engine itself is running properly.

 

[wayne1.8t]

Cheers for the replys guys I'm gona take it for a drive with a bit of cleaner/adds in the petrol and take it back for the retest hopefully will pass so I don't have to pay the£40 again. When got m.o.t gona get myself a copy of vagcom and get it plugged in to see what's what.
I only really use it at weekends so hopefully a good blast might sort it out I'll let u no
Cheers