405 L4-1905cc 1.9L (1989)
Catalytic Converter: All Technical Service Bulletins
Exhaust - Rotten Egg Smell
BULLETIN NO. 387
HYDROGEN SULFIDE "ROTTEN EGG" SMELL FROM EXHAUST WHILE DRIVING
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:
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.
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.