HOW???!!!

[phoenixv6quattro]

Hello Gents hope everyones well?! I,ve been absent for a while due to work commitments so my apologies! ...... The 2.8's just been for its MOT. It passed everything with no advisories, HOWEVER, it failed the emmision test. Now it only just failed (the guy said he would have paper passed it if his boss wasnt present). Now I was a bit suprised because 8 months ago it had new cats and a new Milltek exhaust. It has had numerous treatments with injector cleaner as well as the other usual flushes. There is no prob with the cats or the exhaust, they still seem like new! I'm thinking it could be the Lambda sensors (2 of the/ V6), and wanted to know what you guys thought?

Ollie

 

[aragorn]

Either the cats were too cold, one/both lambdas are faulty, or the CTS isnt right. Our old FWD was marginal, failing its first test, but the guy just wound it round to 3000rpm and held it there, after 2 or 3 minutes the figures dropped right down and it passed. Said that sometimes, the cats cool down too much with the car sat idling and become less effective.

Does the car have any fault codes?

 

[phoenixv6quattro]

Either the cats were too cold, one/both lambdas are faulty, or the CTS isnt right. Our old FWD was marginal, failing its first test, but the guy just wound it round to 3000rpm and held it there, after 2 or 3 minutes the figures dropped right down and it passed. Said that sometimes, the cats cool down too much with the car sat idling and become less effective.

Does the car have any fault codes?

Hello Aragorn hope your well mate. No the car dosn't have any fault codes anymore/at the moment. The CTS is defo the correct one and was changed by me approx 8 months ago. I have a free retest booked in for wednesday. I'm going to give it a good thrashing and get the guy to test it straight away so any dramas with cold cats will not be an issue. I bought two sensors today and if it still dosnt pass going to see if they make a difference. Failing that I really will be scratching my head...

 

[millsy]

whip the plugs out and give them a clean up and re gap.ive seen a few times the injector cleaners can leave deposits around the electrodes.good luck with the re test

 

[phoenixv6quattro]

Thanks Millsy but I have already done this.......Turns out it was the nearside Lambda sensor. Changed it up yesterday and the test results were considerably lower. So we have a pass! Next job??......DE-CAT!! ****** to the law (****** treehugging hippies) and ****** to the enviroment (I need a tan anyway).

 

[Audidave]

My 2.8Q is due its mot soon, thinking about a cat gutting session after, let me know how you get on!

 

[phoenixv6quattro]

Yeah will do mate but I'm not going to be gutting mine, just removing the cats completely and welding straight pipe in place.