Mot Fail

19th July 2008, 23:52

My Saxo vtr had been de cated so for the MOT I had a cat fitted brand new but ti still failed the emissions test. Is it the lambda sensor? Does it just want reseting now it has a cat on if so how do you do it.

I noticed they did the MOT straight after putting the cat on and the exhaust was pumping out smoke a bit this has now cleared so could it now be ok? Should they test it 3 mins after fitting a new cat?

If the sensor is faulty would it have shown up in any way before with no cat if so what would I notice?

20th July 2008, 11:09

some 1 reply coz i got the dredded mot on the 2nd of august and i havent refitted my cat yet.

20th July 2008, 12:32

Get the car nice and warm then get the emmissions done................

21st July 2008, 09:29

It will need time to settle, really they should have left it running for 5-10 mins then tested the emmisions, this should be fine also after a good run.

21st July 2008, 09:36

the mot tester knows to get the engine hot, cants dont work till after you have been driving for about 15 mins.

when you take the car there for retest, drive it hard on the way, get it really hot, then hope they dont leave it sat there all day, it will stay warm for an hour or so

21st July 2008, 21:19

Drive with the CAT on from now until the MOT. If it still fails the CAT is a dud or you have anther problem. But the CAT definitely needs sometime on the car.

24th July 2008, 21:03

i always put some octane booster in with my petrol it says on it that it lowers the imisions and its always got me a pass i start adding it to my fuel about 2 weeks before the mot try this carnt do no harm just follow instructions on the bottle and theres loads to choose from you can even get them in tablet form nowadays 2