what's happening?

I believe that is the Catalytic converter making that smell.

Correct, that's what an overheated catalytic converter smells like. At least, in my experience.

I'd have to concur with Omicron, I've had a number of cats start to smell either "sulphery",(if that's a word! - my English prof would have a fit), or worse, like rotten eggs. Have your cat checked.

Originally posted by Omicron
Correct, that's what an overheated catalytic converter smells like. At least, in my experience.

Actually, it's what a NEW catalytic converter smells like. After a "burn in" period, the smell goes away.

phewww

thanks

Originally posted by MP3Guy
Actually, it's what a NEW catalytic converter smells like. After a "burn in" period, the smell goes away. True, usually. But I had an '86 Celica GTS for a while that always smelled like that, for 85000+ miles.

But in your case flatso, I agree, it probably will go away.

I noticed the smell, then it went a way. A day or two later, CEL came on. Diagnosis: CAT needs replacement. Ascribed cause: prior flooding episode. See the new TSB on flooding, which tells you to disconnect something before trying the start-it-yourself method.

There is no sulfur in a new cat. converter. The sulfur comes from the fuel you use (oil companies too cheap to remove all of it). It builds up in the converter as SO2 and other compounds. Try using a different brand of fuel. The sulfur will destroy O2 sensors and is not good for the cat (can eventually plug it - but this usually takes 5-10 years).

As for the cat. failures in RX-8s, please explain to me how the small amount of fuel added during a flooding event overwhelms the amount Mazda had going through trying to keep the cat cool enough (black grunge in tailpipe dripping out is kind of a hint!).
I think blaming cat failure on flooding is a poor excuse for an originally mistuned car causing it!

I would never be on the other side of a technical argument with David. (Would be like bringing a pillow to a gunfight.) Note my lawyerly use of passive language, "ascribed to." Just pointing to what the March 11 TSB suggested. http://www.rx8club.com/showthread.php?s=&threadid=22989

yes the TSB mentions flooded fuel burn off damaging the cat.

I have been using 87 octane I wonder is that has anything to do with it? I used 93 today and did not notice the smell even when really reving it.

i find i get the smell like poo when i slightly burn a lil bit of clutch any one else think so

Since getting my car back from being reflashed, I have a sulfur smell from the cat. Should I be worried?

that is excessive fuel burning inside the cat. too much and you'll need a new cat. but you shouldn't worry, heat the cat up and it'll eventually go away.

clutch doesn't smell like rotten eggs. fuel soaked cats do. so does battery acid and brake rotor shavings.

I believe when the mixture is wrong, a different catalytic reaction takes place, and one of the by-products is the production of H2SO4, or rotten egg gas.

It shouldn't normally happen when the car is running properly, and closed loop is doing it's job.

Cheers,
Hymee.

I have the same problem as well. It started after I had the car at the dealership for a new air bag.

I assume they would have had the car re flashed. On my first drive after picking up the vehicle I noticed a slight rough idle...which has now settled. However the rotten egg smell has remained.

I wonder if I should take the car back.

skc

Gear oils also have a high sulphur content.

Hymee, H2So4 is Sulphuric Acid....Sulphur Dioxide SO2 is probably what we have here.

Where is labrat when you need him....

O - 4 give me.

I got that wrong. At least I got the symbol correct for the Oxygen. :p

OK, "rotten egg gas" is in fact Hydrogen Sulphide - H2S

My mistake.

Cheers,
Hymee.

You guys got all that chemistry right :) I'm a lab rat too, I guess ;)

HELP...
all i know is that i was driving and as soon as i switched to 2nd gear i heard a snap under my foot... from then on i ouldnt switch gears..... but i could turn the car on and off....
MAZDA dealership is saying that it is my clutch bracket (clutch pedal assembly) .... i have only had the car for 4k miles... they say that they have neva seen nething b4 so they dont know if it is covered under warranty or not.... nor do they know how it couldve happened.....

HELP...
all i know is that i was driving and as soon as i switched to 2nd gear i heard a snap under my foot... from then on i ouldnt switch gears..... but i could turn the car on and off....
MAZDA dealership is saying that it is my clutch bracket (clutch pedal assembly) .... i have only had the car for 4k miles... they say that they have neva seen nething b4 so they dont know if it is covered under warranty or not.... nor do they know how it couldve happened.....

And how does this relate to a sulphur smell?

And could someone please decode it for me :0