Diesels starting and especially when cold are most likely to have a black tinge until the fuel supply is properly managed by the governor system.
Diesel smoke (like blowby and oil use) is a worrying engine symptom At cold start, blue smoke is often evident, and can reflect reduced oil.
There are many common causes for diesel engine smoke from burning oil, fuel or plugs during cold startsand/or the use of a flushing solvent to remove engine.
Ltr Turbo Diesel engine produces a lot of whitish smoke when starting up I wouldn't bother (unless you're doing a 'red arrows' impersonation). Has the engine got a fuel pre-heat system for starting in cold weather?.
I make clouds of white smoke on startup, until the throttle is given full burst for a Cant really see how it can be steam from a cold engine and exhaust! didnt bother when my old Perkins engined diesel Montego used to do it!.
I do notice that on cold starts ( to - 30) it will pump alot of white smoke for 10 or a winter diesel blend that I think may contribute to some of the smoking. If you let the truck idle at a low rpm the fuel will actually wash the oil off the cylinder walls. . At 20F, I wouldn't even bother plugging in even if my espar isn't running.