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My car's exhaust smells like rotten eggs
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Question:My car's exhaus smells like rotten eggs when I start it up in the morning. Why is that?
Answer:On some vehicles, a sulfur smell or 'rotten egg' odor may be noticed coming from the exhaust system. The odor
is usually noticed after a cold start, fast idle, extended periods of idling and full throttle acceleration. Sulfur smell
is not an indication of an engine concern and will not cause reduced driveability or durability of the engine or
any of its emission components.
The sulfur smell or 'rotten egg' odor is caused by high amounts of sulfur in the gasoline being used in the vehicle.
Sulfur is normally eliminated during the refining process, but the EPA regulation of sulfur in gasoline differs
from state to state. Vehicles using fuel containing high amounts of sulfur will most likely emit sulfur smell from
the exhaust system.
When high sulfur fuel is burned, there is a chemical reaction in the catalytic converter causing the sulfur to oxidize.
As the vehicle is driven, the oxidizing reaction odor in the converter will decrease with mileage and age.
Replacing the catalytic converter will not eliminate sulfur smell and replacement will just extend the
period of time needed for the converter to 'age' allowing it to reduce sulfur smell to an acceptable