Its MOT time
 

Checking the mechanical bits is not a problem, the bits that can effect emission is a tad more difficult, so where do I start. I know that I can change the air filter but what else can be done, for example, is there anyway that I can check the MAF without having to use diagnostic equipment, is there any way that a MAF can be cleaned. What about the injectors, is there anyway these can be checked, You input would be appreciated.

Seems that there is not an answer to this question :shrug:

To check all the things you want to check you would be best with a T4 diagnostic session, but to be honest if the car seems to be running ok, doesnt smoke, and pulls well through the rev range then there is probably nothing wrong with it.

I wouldnt worry if you dont have to. my car has 190,000 miles on it and in 14 years I have never had it near a T4. When the MAF's failed it was always pretty obvious from the loss of power in the low rev range.

There is a huge margin of safety below the smoke limit in an MOT. Mine have never come close to failing usually coming in at less than half of the limit.

thundercat, to answer your question, well, the MOT tester currently does a smoke test, not an emission test (as such). There is no reason on these cars to worry about emissions as long as your car is not visibly smoking and is running correctly without hesitation or power problems. Yes you can clean the MAF if you want to but only if your having any of the problems I've mentioned.
If not, then leave well alone. Apart from as you say, a filter change and possibly a fuel filter change ( which should be mandatory if it's serviced regularly ) there's nothing else emissions wise you can do. I have in the past when I had a 25 TDI, took it out for a good revving boot session down the bypass before an MOT and cleared a lot of soot!!. But the L series is a completely different animal to the M47R lump so don't worry and good luck. :}
Regards DaDragon (roger)

David Lawrence, you can type quicker than me, guess you've answered this? :}
Regards DaDragon. (Roger)

Yes just beat you. For reference i also do the booting it down the bypass trick as well. And use shell diesel as well, that helps

Thanks for your input, I shall just change the air filter as its due for a change and leave it at that

Put half a bottle of decent injector cleaner on 1/4 of a tank and give it a good blast will clean your injectors and help it run smoothly. Will help with soot too.:}