Weird Sulfur-like Smell


A woman called in reporting she had a smelly sulfur smelling from her car and asked where she could get better gas. Tom and Ray say the converter has a nickel coating to stop that smell from appearing. What do you think the woman should do about the smell and where can she find better gas?


I think she may need to get another converter. Also I have heard that Shell Gasoline is cleaner and less sulfur. It prevents future build-ups and you get better milage. That is what I have heard and seen in newspapers and of course the commercial. So…I would definitely try that.


My advice would be to ignore it. The condition is generally harmless and it goes away by itself, usually after another tankful of gas. I know, I know, this is not what people want to hear.


Things that can cause a sulfur odor from the exhaust are, high concentration of sulfur in the gasoline, an engine that is running too rich, an engine that doesn’t get up to full operating temperature, using a high octane gasoline in an engine that doesn’t require it, or a defective catalytic converter.



Take that car for about a five mile blast at 85 mph (in most major metro areas you’ll just be running with traffic in the left lane). That will clear the converter out.


In the past nearly all cars with catalytic converters had the rotten egg smell during warm up. The owners manuals even alerted the owner to this, and said not to worry. Unless the car is running rich for some reason, I agree that a fast cross country trip will do a lot to purge the system. Some gas might be a little better than other, but it sounds like the car is slightly bunged up. A diagnostic shop with tailpipe analysis gear could tell you whether the engine is functioning properly form an environmental point of view. If indications are that the converter is not working (poisoned), you should get an new, generic one (after market) or one off a low mileage wreck. A new one from the dealer will be quite expensive.