Late XM V6 24v failed MOT on emissions

[stevelp]

Just had my specialist on the phone. The MOT only (I say only!) failed on CO emissions much to high.
What are the usual problem areas that I should look at to get this passed. I really don't want to have to change the CAT, even if I can find one for a V6 24v.
Cheers
Stephen

[Hell Razor5543]

I wonder if an Italian tune up is in order here? A good blast up the motorway usually helps to clear out the airways and exhaust, and most people I know do this early on the MoT day.

[Stickyfinger]

When I had the ActivaV6 tested it was dreadful and failed with red lines all over .......it needed to get hot so the tester asked me to take it up the road and back....it then sailed thru with really low results that even surprised the tester at how clean and smooth it was running.

I would say as above, it needs to be warm/hot and that should be done before any work.

[xantia_v6]

I have also had trouble with ES9 engined cars with getting the cat warmed up for the test. It is worse in winter.

On my old Xantia V6, after about 150,000 miles, the tester had to "idle" the engine at about 3000 RPM for 2 minutes immediately before the test, and the emissions would come down to near 0. I have had another couple, which while not so bad, would always require a couple of test runs to "warm up".

Beware of the cheap (small) aftermarket cats now available, they have a reputation of only lasting a year or two.

[momag46]

I agree - It needs a good blast.

When I bought my Xantia V6 it had not been used much and probably never been thrashed, it was also low mileage.

It just crawled through the first MOT I had done and the tester said it just needed a blast. The next year it sailed through but I'd took it down a fen road before the test, was it hot, you bet.

Maurice

[DHallworth]

I echo what the others have said, take it for a good thrash and ask the specialist to test it as soon as you get back.

Failing that, if it's a small aftermarket cat that is on the car you'll probably have issues with it. Failing that, it is possible you have a lazy lambda sensor. Sticking the car on a Lexia will confirm this though.

David.

[BX]

Again what is needed is a logical approach. I never give in to the stab in the dark methods. The problem is likely to be the cat BUT the operation of the lambda sensor needs to be checked. Is the engine breathing a lot of oil vapour. What are the spark plugs like? A visual inspection can tell a lot. What is the air filter like?

[CitroJim]

Have you had it on Lexia/ELIT diagnostics and checked the Oxygen (Lambda) sensor is working properly?

I've had an XM V6 and an Xantia V6 that had quite an appetite for them. Be aware that if it has a cheap eBay generic one fitted they often, in my experience, have a short life...

Also, if you have a replacement cat fitted that is much smaller than the huge original These can be a bit marginal and again need to be got good and hot to pass...