Enes : Hello and welcome to our web page here my name isXXXXX a Certified Volvo Car Expert Mechanic.I'm going to try today to answer your question.
Enes : you must check maf sensor ,temp sensor and oxygen sensor using scanner monitor see if they work correct
Enes : also check vacuum air leaks
Enes : but best way to help is using advanced scsnner you get more Infi
Enes : What cause black smoke in diesel engine?Black smoke is usually too much fuel or not enough air It may be as simple as a dirty air filter. Start with the easy stuff first.
Enes : Most common causes of black smoke are faulty injectors, a faulty injector pump, a bad air filter (causing not enough oxygen to be supplied), a bad EGR valve (causing the valves to clog) or even a bad turbocharger. Some of these are easy fixes.xx
Customer: I have checked the air filter and that looks new and had sensors checked so will get it checked for air leaks thanks
Enes : All you can do visual at home check
Enes : all other test you need gauges and scanners