Smoky CDi

[daveandfleur]

My Vito 108CDi has gradually become more smoky over a period of a few years but has always passed the MOT to my surprise. It has never used a drop of oil so I'm assuming diesel smoke. The MOT is coming up soon and I'm convinced it is too bad to pass again. I'm leaving quite a cloud behind on hard acceleration. It's done 150,000 and is very rusty so it's not worth spending much on it but has anybody any ideas of likely cause? It runs perfectly and I've not touched the diesel system since I bought it five years ago at 100,000. If I can get it through for another year without spending a fortune then I'd be happy.

Any suggestions welcome.
Thanks
Dave

 

[Danny DeVito]

Stuff called Dipthane i think it is, add to diesel . A friend used it on ford mondeo and it took about 60% off emissions . Maybe it would help

 

[wemorgan]

I've read that some people highly rate Millers diesel additive.

 

[jaymanek]

Yes you need some diesel cleaner in a strong dose... Should clear it out enough for the MOT.

 

[Gedly]

You say you haven't touched the derv system, does that mean fuel filter is the same one? I would advise changing the fuel filter and air filter as these can cause smoking issues. What you should do is get a new fuel filter and get an injector cleaning treatment from a motor spares shop and fill the fuel filter with it when you fit it as this will give you a more intense clean to start off. Smoking can be caused by a poor spray pattern (poor attomisation)from the injectors if the nozzles are carboned up. Also not enough air coming through the old air filter will lead to the same kind of fault as not enough air to fuel ratio.

 

[daveandfleur]

Thanks for all the replies folks. Have changed air filter but never fuel filter. Will give that a go filled with additive as suggested. I somehow think it will be more than just an additive needed. There's a lot of smoke!

Dave

 

[Tony Russell]

http://www.mbclub.co.uk/forums/engine/72585-vaneo-diesel-1-7-cdi-excessive-smoke.html

Try the stuff I did - clean out the oil separator and the EGR etc.

I also found that if I drove about with the dipstick up slightly, the smoke stopped - like there was pressure building up somewhere and forcing bad material down somewhere. The dipstick releived this.

 

[Baron_Samedi]

Good Points Tony.

Oil sloshing around the EGR is often the cause of smoking.

 

[Gedly]

Usually if you have to pull the dip stick out abit your engine is breathing heavy and you may find your piston rings are worn letting the compression into the sump. Some times they have a breather filter in the system which may need cleaning.

 

[daveandfleur]

Thanks to all. Surprisingly I found the air filter to be the culprit, even though it had been changed about a year/6000 miles ago. Tried running without it and virtually no smoke at all. Doesn't look particularly dirty either. Can't remember where it came from but wonder if it was substandard quality.
Dave