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My car's exhaust smells like rotten eggs

 

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Question:

My car's exhaus smells like rotten eggs when I start it up in the morning. Why is that?

Answer:

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 driveability or durability of the engine or
any of its emission components.
The sulfur smell or 'rotten egg' odor is 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 will 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.
  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.
  4. 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.
    A website to check is: EPA



Comments:

You are on page 1 of 5, other pages: [1] 2 3 4 5
2009-10-12, 14:19:38
anonymous  
rating
Strong sulfur smell means that you are running a rich air/fuel ratio. Sometimes this is normal especially during warmup. If your engine is warm already, this is not normal and fuel pressure or sensors should be checked.
2009-10-29, 16:03:59
anonymous from Oak Park, United States  
rating
hi,u should try change the oxygen sensor,its only 25 dollars on ebay.u can do it ureself
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My car's exhaust smells like rotten eggs



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2009-10-29, 16:04:46
anonymous from Oak Park, United States  
rating
hi,u should try change the oxygen sensor,its only 25 dollars on ebay.u can do it ureself
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My car's exhaust smells like rotten eggs



Keywords:
2009-11-02, 21:50:39
LaurieFrank105 from United States  
I just bought a car that had sat for a while. It is 97 Saturn SL1. After driving it home I noticed a foul odor resembling rotten eggs (while idling). The man just replaced the oxygen sensor the day before I bought it. Should I now assume that it is the catalytic converter?
2011-12-22, 16:24:40
anonymous from United States  
Our 03 Pontiac grand am just had this problem along with a putting. It was the engine pull. Coil and head gasket area. Costs 170.
2012-02-22, 16:28:50
anonymous  
The best thing to do is scan your car for codes. Is their a check engine light on? Some times it won't come on while having issues. In my experience, it has been that the motor is working too hard and when you romp on the gas then let off it gives it an extra squirt. This fuel gets in to the combustion chamber and burns off. With the upward force while driving it can penatrate your ventalation system. Inwhich case you will smell it. Also, their could be a misfire some where on a cylinder. Get it looked @ before the motor goes. I replaced my cat then 3 days later the motor siezed!! I replaced a lot of things before that. Good luck.
2012-06-11, 10:29:02
anonymous from United States  
An engine that is not well tuned will send some unburned fuel down the tailpipe, leaving it for the cat to clean up. Sometimes if it is not a bad misfire, the computer will not store codes.
Replace plugs and coil boots/wireset
Clean MAF
Check PCV system and Air Filter
You are on page 1 of 5, other pages: [1] 2 3 4 5

 

 

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