Exhaust - Rotten Egg Smell

90peugeot05 BULLETIN NO. 387


DATE: JUNE, 1990
SUBJECT: HYDROGEN SULFIDE "ROTTEN EGG" SMELL FROM EXHAUST WHILE DRIVING

MODELS: ALL VEHICLES

With today's newer more efficient 3-way catalytic converters, there is a greater tendency to store sulfur on the catalyst material during steady-state driving conditions, such as highway cruising, slow moving heavy traffic, etc... This sulfur can then be released as hydrogen suffide during transient periods of fuel-rich operation such as heavy acceleration. This sudden release of hydrogen sulfide can be characterized as a smell of "rotten eggs".

Since this is a normal occurrence, no attempt should be made to replace catalytic converters or other fuel injection components to alleviate this condition. However, there are a few suggestions you can make to your customers who occasionally experience this odor:

1. Premium fuels generally contain considerably less sulfur than regular fuel. Therefore, a switch to a higher octane gasoline may somewhat reduce the level of hydrogen sulfide odor.

2. The ability of these catalysts to store and release hydrogen sulfide is reduced with age. Therefore, as a vehicle accumulates mileage, this condition will most likely correct itself.