Black smoke from an engine is caused by unburnt fuel.
The most probable cause is combustion of a rich mixture of fuel.
Black smoke coming out of the exhaust of a car is usually due to oil being burned in the engine's cylinders. This can be caused by a worn piston ring or rings.
Black smoke in your exhaust is a sign of your car burning oil. You should have a qualified mechanic inspect your car and make the proper adjustments.
one of the causes of all three symptoms is a bad fuel injector
white smoke can be either your car overheating, or smoke from an electrical issue
Unburnt fuel
take it to the car shop
to much fuel. gm jim Fuel to air mixture too rich or choke stuck on.
blue smoke is oil. white smoke is water. black smoke is unburnt fuel
condensation
Unburnt fuel
Thick black smoke can be produced by a variety of things, including the burning of some kinds of plastic.