Sulfur Smell. Cat Issue?

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So on and off, I have noticed a sulfur smell when driving the Focus on hills. I just assumed it was from other cars that I was following.

Last night I was unloading some bikes from the back of the car with it running and I could smell it again. Decided to sniff the exhaust (I'm sure my neighbors thought I lost it ...) and it's a pretty strong sulfur smell coming out of the exhaust.

Does this mean it's running really rich (gas mileage is reasonable, I think) or that the converter is on its way out?

With 47K on the car and only 3.5 years old, I believe this should be covered if it's bad.

I'm guessing this would be a result of all of the short tripping I did when the car was new?
 
Currently gasoline in the US doesn't have all that much sulfur, so you should not be smelling it, unless you filled up with some gasoline of questionable quality.
 
Try a few tanks of Top Tier gasoline in the recommended octane level. Sounds like a fuel problem.

If it continues check your warranty. Emission controls should have a longer factory warranty. Check your owners manual if the problem persists.
 
I think its a combination of fuel type and fuel map. There is a span of Toyota vehicles, circa late 90's to late 2010's, that are VERY prone to that smell when under a heavy load like climbing a hill. To the point that I smell it in traffic and I tell my wife 'I smell a Toyota or Lexus ahead,' she looks up and finds the car 3 ahead of me, and tells me I'm a strange freak.

But regardless of the fuel map, the sulfur has to BE there in the fuel, so maybe try a different brand for a while. The law sets an upper limit, but I think many brands have even less than that.
 
I'd try a different brand of fuel for a while to see if it clears up. Back in the 90's, it seemed like Shell gas caused my vehicles to emit a sulfur smell. I know specs have changed since then, but changing gas brands is a cheap first-step, IMHO.
 
I have been using Sams club gas pretty much exclusively for the past 10 months. It is delivered by the same trucks that deliver most of the fuel around here "Terpening" company.

I will trying switching gas brands. I usually end up filling up around 1/4 tank on this, so I'll let the tank run lower than I feel comfortable and try a different brand.

So, it's not a definite sign of a failing cat?
 
Isn't there a sensor behind the cat that would throw an error code or check engine light if the cat was not working correctly?
 
Originally Posted By: Quattro Pete
Isn't there a sensor behind the cat that would throw an error code or check engine light if the cat was not working correctly?



Only if it's below efficiency or not coming up to temperature.
 
Is your tail pipe carboned up?

Maybe need an italian tuneup to burn off crust on the catalyst surface- otherwise its related to fuel sulfur content. Most fuel in a locale comes from the same terminal the only difference being the specific brand additisation.
 
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I have experienced that sulfur smell coming from my 04 V6 Camry once in awhile over the years. Never had the "Check Engine" light come on so assumed it was the fuel.
 
Originally Posted By: ARCOgraphite
Is your tail pipe carboned up?

Maybe need an italian tuneup to burn off crust on the catalyst surface- otherwise its related to fuel sulfur content. Most fuel in a locale comes from the same terminal the only difference being the specific brand additisation.


Clean as could be! Every other week (or so) it gets driven on a 140 mile round trip on the highway. So it runs at 2500RPM for 45 miles, then the rest of it is a bit slower, but still 55MPH for 20 miles. Then back again.

I do drive it light. That would get it up to temperature to "burn" the stuff out of the cat
 
Originally Posted By: bigt61
Plugged air filter might make it run a little rich too.



Not on any modern fuel injected engine.
Sure in the carb days this may have been an issue however a fuel injected vehicle adjust the a/ f so even if the airway is restricted once the engine has warmed up and it's reading the o2 sensors then there isn't much chance of it running rich,not for that reason anyway.
 
The sulfur / rotten egg smell is basically hydrogen sulfide. Typically, the small amount of sulfur in the fuel is converted to odorless sulfur dioxide. When the catalytic converter stops working because the filtering layers have worn down, the sulfur is not transformed into the odorless form we expect. Therefore a strong sulfur / rotten egg smell is produced.
 
Leaking gear oil has a sulphurous smell, so does ATF on the exhaust pipe. It doesn't take much of any fluid on the hot exhaust to make a really bad smell.
 
If I understand it correctly the sulfur smell isn't from a bad cat (its trying to do what its suppose to do) its from extra rich exhaust reaching it usually a temporary result of an engine under load.
 
It could be an oxygen sensor(s) that is on the verge of failure. My 1993 Chevy truck once started putting out a rotten egg smell. Finally the CEL came on because of a failed oxygen sensor. Replaced the sensor and the stink went away.
 
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