I've heard that smoke from exhaust on rotaries is normal and i know its some to burn oil, but my car doesn't smoke at all unless i reach about 5-6k rmp then it won't smoke till i let off the gas. As soon as the rpms start to drop a cloud of smoke leaves the tail pipes. Its not sweet smelling so i praying its not burning coolant. If anyone can help please tell me what to do/try or what it could be. Just for the record i am running 3 inch pipe off the stock exhaust manifold with not cats to a racing beat cat back sytem on an 86 non-turbo.

 

Sounds like either a decleration system failure (ie: Injectors not cutting fuel) or bad Oil Control Rings inside the engine. If you've got quite a few miles (120,000+) then it's probably the OCR rubbers going bad, which require a rebuild to fix.

the only other thing that I think it could be is a bad Metering Oil Injector (actually, they function more like a "dripper").

Have a friend stand by the side of the road and do a "drive by." Make it smoke close to him and have him describe the odor of the smoke. If it's sweet, it's coolant. If it smells like a dirt bike (or any old American car's exhaust), it's oil, and if it feels like he's being maced, it's gas. If the smoke is white, it's coolant. If the smoke is blue/black, it's oil. If the smoke is dirty-white, it's fuel.

 

your oil control rings are worn
put some MMO in your oil
and switch to a slightly higher weight