Failed MOT Emission test

Start by looking for things like cracked/split vacuum hoses. Sometimes something very simple can screw the whole thing up.

I.

A reading of 9 is very smokey! Have you noticed excess smoke recently, or was the car not properly warmed up or not purged before it was tested?

Borderline Diesels need to be fully hot, and preferably run with a strong injector cleaner in the tank leading upto the test, dont forget to give it a goodly thrash to blow out the accomulated carbon from the exhaust too.

A new airfilter and fresh oil are obviously needed to begin with.

Tim..

Long blast at flat out in third till it clears up, obvious stuff like air filter. Fresh oil can reduce the smog a little. Stinking hot when you go for test. If it still won't get anywhere near the magic three, first check the timing then a recon set of injectors (unless recent anyway). If it is very close but not quite, then a bottle or two of cleaner can reduce it a bit, some people even shove some paraffin in the tank for the test (I wouldn't) Other than that, take it to a diesel specialist and ask them, it may need a pump.

mrcheerful

Get the oil and filter changed, and fuel filter and air filter. Then get the engine nice and warm, and take it for a really good blast, running it right up to the redline in all gears, and holding it there for a good while (but for heaven's sake make sure it's *properly* warmed up before doing this). When you get back to the MOT station, leave it idling for a good minute or two after that sort of hard treatment, including driving it gently for the last mile or two, then that should do the trick.

Either that, or a new set of injectors.

That's exactly what I did for my last MOT with my '99 Rover 200 diesel (same engine as OP's 400), and had a PM reading of 0.17 on the test... Mind you, that did include a blat at 120mph on the testing circuit we have at work...

snipped-for-privacy@derby.ac.uk wrote in news:1123587557.363303.107400 @g49g2000cwa.googlegroups.com:

You have a testing circuit at work? You jammy bugger! Got any jobs?

Don't forget to change cambelt if required!

Yep -

I love my job - regular opportunities to thrash Jag/LR/A-M cars to the limits :-D

No vacancies at the moment I'm afraid though!

Andy

Before or after?

Thanks for all the helpfull advice. Someone at work suggested putting 3 litres of petrol into half a tank of diesel ????

Hi

Had a similar problem with my Audi 80TDi Avant (1995). Currently on 145k. Try a can of Forte diesel conditioner straight into the fuel filter resevoir. Change oil and filter (consider using STP engine cleaner) prior to draining) and fit a new air filter. Also double-check breather hoses - as they get quite dirty over time.

As suggested - run the car in 2nd or 3rd gear with high revs. You should see black smoke initially as the carbon/soot deposits are blown out. Double check your timing belt is up to the job - and isn't in need of replacement prior to doing this.

You'll need to replace the fuel filter on completion - as Forte doesn't do it any favours.

Good luck.

Spart

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