SULFUR-LIKE SMELL FROM THE EXHAUST SYSTEM (Porsche Technical Bulletin)
Contributed by: Ray Calvo
(For all models)
A sulfur or rotten egg smell might not indicate any problem with the vehicle, but is likely a fuel problem. Sulfur found in gasoline is normally converted via combustion and the catalytic converter into sulfur dioxide (SO2). Under certain operating conditions (when engine is running rich, such as heavy acceleration or under a heavy load), hydrogen sulfide (H2S) might be formed instead, which gives off the sulfur/rotten egg odor. To what extent this occurs depends upon the sulfur content of the fuel and the operating condition of the catalytic converter.
If a car is exhibiting this phenomena, first thing to do is to run an engine diagnostic to ensure that the mechanical and fuel systems check out OK. If no problems are found, it is then advisable to switch gasoline brands.
Porsche has noted that if there are no problems found in the engine or fuel/emissions equipment, replacement of such components as oxygen sensors or catalytic converters will not reduce the smell, and will therefore not be considered a warranty matter.