If the turbine is making an odd noise, it is likely that a piece of metal or other debris is floating loose inside the turbine can. Immediately turn the unit off. The turbine will have to be replaced.
If the turbine is smoking, this is likely due to an excess buildup of paint on the turbine filter. Turn the unit off and remove the turbine filter or filters. If this area has not become warped, clean or replace the filter. If the area has become warped, the sprayer ran too long with a clogged filter and the turbine will need to be replaced.