exaust that smells like rotten eggs

[98outbackpdx]

my grandparients had a 99 fozzy "s" and the exaust smelled like rotten eggs, they kept taking it back to the subaru dealer and the dealer could not find anything wrong with it. it is a mute point now since they don't have it and they replaced with '05 LL bean fozzy, but i remembered that smell and car and am wondering what caused that smell. it was not the cats they had them checked. any ideas?

[rudgers73]

gotta be the cats. Or I guess if there was some sort of issue with incomplete combustion or something it would be a root cause. Rotten eggs = Sulfur-based compound. That only happens when gas is burning wrong or a cat isn't doing it's job.

[skippymo]

gotta be the cats. Or I guess if there was some sort of issue with incomplete combustion or something it would be a root cause. Rotten eggs = Sulfur-based compound. That only happens when gas is burning wrong or a cat isn't doing it's job.

cats, are really the only egg smell that would come out of your car. rudgers73 couldn't say it better myself.

[ouch1011]

Our shitty gas in the US has high levels of sulpher in it. The cats filter out most of the smelly stuff from the exhaust, but doesn't do anything with the sulpher. So when you get a lot of fuel in the cats (or just generally a lot of exhaust flow, such as high engine load, driving up a steep hill, passing a car, etc), the sulpher smell is all that is left.

If it only really happens at or shortly after having high load on the engine, its normal. If it happens all the time, it can be an indication of a problem.