My TDi 1.9 A4 puffs a bit of sooty black smoke from the exhaust usually at gear change. To be fair I think it has done this for quite a few years but a mate drove it last night and as I was following in my work car I noticed it - now it is dwelling on me as I have the yearly car check coming up in early Nov.

One of the testers a few years back said I should rev the engine a few times immediately prior to the emissions test just to 'clear it out', someone else stated to use a fuel additive as to clean the injectors, another said drop in some petrol to 'burn off' any deposits.

As many of you work for Audi I would appreciate your comments/thoughts and advice. I should add that the fuel and air filters were changed by Audi very recently as part of service regime.

 

never put regular petrol in a diesel engine.

im not too familiar with the TDIs in particular but with any car you should drive 'spiritedly' every once in a while, wind it up to the redline a few times. that works better then just reving it. if there is no other problems, i really wouldnt worry about it that much.

 

Thanks Ghost, appreciate it. There are no other problems - car is great.

I am in Sweden and one can get banned for being 20% over the speed limit. Say for instance doing 40 in a 30 limit will earn a few months public transport time! So I have learnt to drive like an one armed granny - probably causing that build up of soot.

Any thoughts on the additives?

 

Additives generally do what they're supposed to so you should be safe to use those. If you have access to seafoam there, I would recommend trying a full treatment and see if that helps any.