Meanings of the smoke for the upcoming papal conclave:

Black smoke means they're burning oil, which could be a sign of piston ring or valve stem seal wear

White smoke means they're burning coolant and the papal head gasket has blown

@tryst

Blue smoke means they put the capacitor in backwards.

@futurebird @tryst
Green smoke means the copper wiring is burning and someone should really go check on them.
@bruce @futurebird @tryst or it could be the engine throat or nozzle - those are made of copper too