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rotten egg smell

rotten egg smell

Postby bradman0087 [OP] » Mar 01 2012, 2:31am

some times after i back up in the drive way i notice a rotten egg or sulfur smell.. I was always told this is a sign of a partially clogged cat convertor.. what is your experience? dont we have 2 cats? how do i know which one?
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Re: rotten egg smell

Postby 1500VHO » Mar 01 2012, 3:21am

Hi Bradman,

My experience and after discussing with my mechanic friend - Josh...

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 drive-ability or durability of the engine or any of its emission components. You mentioned when you back up. I'm assuming the smell is after a start-up... Plugged cat converters do happen, but today's Catalytic's are much better than yesteryear... Another check you can have completed, is your O2 sensors.... But if your check engine light is NOT coming on, I'll assume they are Ok.

The sulfur smell or "rotten egg" odor can also be 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 may 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 level, if it is the gasoline in your area having more sulfur.

1) Switch to a different brand of fuel and drive the vehicle for at least 100 miles. Monitor the decrease or increase in sulfur smell.
2) Do not add any type of "fuel additive" as this could add sulfur to the fuel and cause/increase the odor.
3) Try to avoid extended periods of short trip driving or aggressive acceleration, if possible.
4) You could request information from your local fuel dealers on the amounts of sulfur in their gasoline. Try to use fuel containing the lowest amounts of sulfur.
5) Visit the EPA and gasoline company websites to stay informed on any changes in fuel or environmental regulations for your area.

I hope this helped, :D
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