what causes black smoke on diesels,got an old 2.8 td pajero you notice it more at nite with head lights behind you , see it most when u boot it, its got a kind of screetch from turbo when on boost could this be related?

 

Normally just unburnt diesel

 

what causes it to have unburnt fuel though ???

 

Running rich, its soot.

Petrols do the same to a lesser extent.

 

seeing as its an old diesel id hazard a guess at a worn or sticking injector, allowing fuel to drip into cylinder.

 

Black smoke as said is fuel but may be your turbo as you say it sounds noisy, so not making the boost, so you are having a richer mixture with the result being black smoke chucked out the back.

Martin

 

clogged up air filter can cause black smoking too IME, as less air flows.

 

Diesels will kick out black soot when you boot it, as it cleans the system out to an extent.

 

its deff got a strange noise from turbo , and only seems to be bad when on boost,like when on kick down to go up hill, its almost like a fan belt screatch, people i have spoke to about it ask if its loosing power but its hard to tell as there slow as shit anyway !

 

i serviced it mate changed air and fuel filter

 

unburnt fuel.

Ive smoked out a few people when theyve been unwise enough to stand behind my landrover on start up

As has been mentioned, its due to a number of contributing factors

usual service items like airfilter, fuel filter

Worn items like fuel pump, injectors.

Also things like a cracked or small leak on a turbo vacum hose, even a pin hole size can have an effect.

I wouldnt worry too much, unless is very heavy smoke. Like those old transits you see doing a james bond smoke screen down the dual carrigeway.

If its just on start up and under heavy load dont worry. Even brand new diesels will puff away if you floor them.

 

thanks guys

 

Diesels put out particulates that petrol engines don't, the light of a car headlight illuminates this really well, will happen when all is well, as well as when overfuelling, happened on mine even when on 100% bio, no turbo, no overfuelling.
tabetha