Ssssssssssssssssssmokin
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Colonial

Original Poster:

13,553 posts

236 months

Tuesday 30th March 2010
quotequote all
Slight issue with my S3. Just replaced the MAF as it was gone (bad idle, not running well at all, ran fine when I unplugged it etc) and car runs great again. But now it is running very rich in 4th gear – botted it to get onto the motorway and felt like it hit a flatspot in 4th at around 4000rpm and noticed a fair bit of black (and it was black, no blue) smoke coming out the back.

Only replaced it yesterday, and this is the first time I’ve driven it since so should I wait and see or get something sorted quick smart? And is it a dodgy MAF or something else? It’s a MY01 AMK engine. No chip but running cams, APR R1 diverter valve, N75J valve, BMC CDA, dump pipe and exhaust.

ymwoods

2,194 posts

208 months

Tuesday 30th March 2010
quotequote all
Sorry I know nothing about the engine so I am going to ask the noob question.

Is it petrol or Derv?

If it is diesel then I would hazard a guess that its just the particle filter cleaning its self.

If it has not been driven fast and/or the MAF sensor also did not allow the DPF to clean its self then it will have gotten very dirty and taken the first oppertunity to clean its self once you got up to a high enough speed. Since it was "extra" dirty you would have noticed the extra smoke.

Colonial

Original Poster:

13,553 posts

236 months

Tuesday 30th March 2010
quotequote all
S3 – 1.8 turbo petrol.

It just happens to look like a diesel at the moment.

Still, could be worse, could be blue smoke biggrin


ymwoods

2,194 posts

208 months

Tuesday 30th March 2010
quotequote all
Colonial said:
S3 – 1.8 turbo petrol.

It just happens to look like a diesel at the moment.

Still, could be worse, could be blue smoke biggrin
Very true!

Sorry I couldn't help frown

Tame Technician

2,467 posts

235 months

Wednesday 31st March 2010
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Its was probably just clearing out, after a period of not running right the cat my have been full of unburnt fuel, try it over 4000 revs some more and keep an eye one it.

If it does it all the time then you may have another issue as well as the MAF, I take it you cant hear a boost leak at all??

istoo

2,365 posts

233 months

Wednesday 31st March 2010
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maybe have a double check around the hoses/ cables to the MAF and surrounding area make sure its definately sealed up nicely?

Colonial

Original Poster:

13,553 posts

236 months

Wednesday 31st March 2010
quotequote all
Tame Technician said:
Its was probably just clearing out, after a period of not running right the cat my have been full of unburnt fuel, try it over 4000 revs some more and keep an eye one it.

If it does it all the time then you may have another issue as well as the MAF, I take it you cant hear a boost leak at all??
Oh, it's been tried over 4000 for quite a while now. Still there, but might be getting a bit better - the smoke is getting a bit smaller in volume at least.

It's running really well (actually going over 4000) so I'm not 100% concerned, I just don't like looking like a diesel.

No sound of a boost leak - but the noise of the bmc tends to drown most things out so a little hard to tell. It doesn't feel as if there is a boost leak anywhere.