Vectra C Emissions Test Fail

[Baker7]

get cataclean for petrol and drive it like you stole it for at least an hour or so before the re-test... that should do the trick if it doesn't pass it just means you are driving around with dirty oil,a dirty oil filter, cheap fuel and an old dirty air filter... and if that is the case you might want to put in new sparkplugs also... go for a re-test and pass with flying colours ...

because readings like that in most cases are down to neglect.... and i am sorry to say they did the right thing.... something to do with the engine and usually it is neglect.
@nikroc, he probably brought the car back after the week they give you for a re-test, and if that is the case they'll re-test the complete car.

Yes it was neglected before I got it I only had it 9 months but has been looked after since I have had it. Yes you are right it was about 4 weeks later.

[Baker7]

You might have a problem with the front lambda sensor, or an exhaust leak at the manifold, or crack. I had an Astra that failed emmissions and I did everthing including the Lambda, but turned to be a crack in the exhaust manifold, got feed up with it and scrapped the car.

Like I said it defiantly had a leak at the manifold as since last time it failed I have checked the exhaust and found that the bolts on bottom of the manifold was not tight and was quite loose and air was escaping as there was bubbles coming from it till i tightened them up

[Baker7]

You shouldn't use Cataclean just before the MOT for two reasons. One, you would want it to have finished cleaning the cat, not still be in the process of throwing dirt out of the exhaust. Two, Cataclean needs to be used in a high concentration, so you would not want the engine to be running on Cataclean whilst the emissions test is being done. It's a cleaner, after all, not specifically a fuel.

In addition, I don't know how the 1.8's ECU reacts to sustained high throttle use, but the Z20NET, for example, would run a richer and richer fuel/air mix, which is not ideal for an emissions test. Ideally, Cataclean should be used a week or so prior to the test so that there is time to flush it completely out of the fuel system, and the "drive it like you stole it" should be done a few days prior to the test, so that you then have the chance to drive the car gently for an hour or so before the MOT which will give the ECU time to switch to a leaner an leaner fuel/air mix. The more air and less petrol being burned, the cleaner the emissions, surely.

That might be where I’m going wrong as I basically filled the tank quarter way with premium petrol and then added the cataclean and drove it for about 15-20 minutes at high revs this was all the night before I took it for the test and tested it with the same fuel it still has it in now I haven’t filled up since doing it.

[northpole]

I might be wrong about how cataclean does it's work but I used it with succes, granted I drove it like I stole it but did that a month before the actual mot was done... result was an emissions reading of absolute 0... and that is a result and a half on a DTI. Especially since on the previous mot it just about passed the emissions test.

[nikroc]

Personally id ask some straight questions and go to the local DVLA centre..the things it failed on should,imho havre all been picked up on in the first MOT. you paid for ..FFS

[MrF]

MAF could be dirty, had a yaris that barely scraped through the emissions, took out the MAF, sprayed some cleaner on it, tested again passed no problem. Dirty MAF means it can't accurately read the air flow volume so overfuels.

[jasonkurtsdad]

i used cataclean then went for a good hours thrash.....bottle into 1/4 tanks...worked a treat