could be relay 109 that needs to be changed, could also be a dirty injector (mainly number 3) or the timing is off, or the injection quantity is too much causing extra diesel being sprayed in at a cold start... All of these give excessive with smoke on a cold start that disappears as soon as the engine starts to warm up (smoke is there for about 1 minute but the car idles fine)
PS worst case scenario is a leaking head gasket but that means you will have white smoke all the time and the exhaust fumes will smell sweet rather than smelling of diesel.