it sounds like you have an exhaust leak near the front of the car. check all exhaust connections. with the engine cold, start the car and feel for exahaust pressure at all exhaust connections. do not touch the manifold or any of the pipes, just hold you hand near the connections. feeling for leaks is often better than listening when the leaks are small. often times you won't hear them over the engine noise or you won't be able to tell where they are. if it is an exhaust leak: tighten the connection, weld the crack, or replace the part that is leaking.
86' 190e 2.3L 16v