Hopefully i can help..
What colour is the smoke?
Any warning lights or any unusual noises from the engine itself prior to fault or at present?
Hi..there thanks for getting back..
Ok..there maybe a few reasons but of course the obvious areas would need to be checked in regards XXXXX XXXXX restrictions you can see in reagrds to the intake / intercooler system pipe work especially and any obvious issues you can see in regards XXXXX XXXXX system - by making sure they are all fully connected and dont show any signs of tears or splits - if you hear a hissing noise then it most likely thats whats ahppened and would be a case of folowing the intake intercooler system pipe work route checking as you go - one other common could be a failed MAF but again usually those do flag up a warning light if faulty so maybe have that checked out - Another area to maybe try cleaning is the EGR valve "exhaust gas recirculation valve" - This can be a very common area to cause the above syptoms if the valve has become stuck or simply too clogged up with soot or has a flow issue,those can be removed and cleaned aswell as the oriface in which the valves fits too - and then refitted and then see how that goes - so again this would certainly be one of the areas aswell as above to be checking anyway...the usual causes for black smoke from the exhaust can be down to either.the fuel system is delivering too much fuel into the engine or there is not enough clean air (oxygen ) either due to problems in regards XXXXX XXXXX as above,loose pipe work - Faulty injectors "check oil level / listen for any missfiring" / Faulty injector pump "prob unlikely" / Restricted airflow or dirty air cleaner/ Diesel Fuel Filter / Turbocharger "listen for any obvious issues from that" high pitched noises etc" or intercooler faulty / clogged up due to faulty EGR (exhaust gas recycling unit).so as above those are usually the most common problems we often see that can cause black smoke on these..I do hope this helps