206+ anthems late

Hello friends. When I start my 2011 model 1.4 hdi 206+ vehicle, I immediately stop and then start and start for 3 5 seconds or even longer. Meanwhile, it is also that black smoke is exhausted from the exhaust. what's the problem

injectors - fuel filter and hoses - crank speed sensor - diesel pump - sender etc. My teacher may have trouble with one or more of these. Make the most beautiful vehicle with the original software. Possible crank speed sensor. otherwise my other articles will be checked one by one.