fart smell accelerating with ac off, but not when ac on
07-17-14, 11:57 AM
#16
The rotten egg smell means that the catalytic converter is working properly. "It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately. "As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell!
07-17-14, 04:21 PM
#17
The rotten egg smell means that the catalytic converter is working properly. "It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately. "As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell!
The more sulfur there is in the gasoline, the more H2S is built up and released by the catalytic converter,
so the stronger the smell.
In California, where low-sulfur gasoline is actually required by state law, sulfur smell complaints are few
and far between. Low-sulfur gasoline was phased in nationwide between 2004 and 2006.
Condensation, dust, and pollen inside the evaporator case can cause mold to grow and leave a musty
odor when you turn on the A/C. As others have said, cabin filter is the first fix. If that doesn't fix it, Cleaning the evaporator case manually should take care of it.
Last edited by Sceanzo; 07-17-14 at 04:27 PM.
07-17-14, 07:00 PM
#18
Rookie
Thread Starter
Did you have the AC "Circulation outside mode" on? If yo did, outside air would comes in and comes in strong when you accelerate hard. Just put the AC "Circulation inside mode" on and you won't notice the smell.
Change your AC cabin filter with the De-odorization version as well.
AC usually smells a bit when first turn on, i notice this in many cars but it seems weird that the smell goes away when AC on in your case lol.
Change your AC cabin filter with the De-odorization version as well.
AC usually smells a bit when first turn on, i notice this in many cars but it seems weird that the smell goes away when AC on in your case lol.
07-18-14, 01:13 PM
#19
If you have a mildew type smell in cabin, try using some DampRid to get rig of it. I just hang one on the back of one of the front seat's back pockets. Though hard to tell until you pick up the bag, the ENTIRE bottom pouch quckly fills with water (<$10 Walmart for 3 hangers).
The first bag got rid of my smell; but I'll go ahead and use the other two since I have them.
The first bag got rid of my smell; but I'll go ahead and use the other two since I have them.
07-18-14, 01:56 PM
#20
Wow Gville350, when did you become a chemistry teacher? 
Car chemistry 101 right there lol
Car chemistry 101 right there lolThe rotten egg smell means that the catalytic converter is working properly. "It's (the smell) hydrogen sulfide or H2S. It does not exist in the fuel or oil, which is why you can't smell it at the gas station. It does, however, come from the gasoline. Almost all gasoline contains organic sulfur compounds with sulfur levels ranging from 30 to 100 parts per million, approximately. "As the fuel burns, the organic sulfur compounds break down into simpler compounds. If the engine is running lean (more air than is needed to burn the fuel), the sulfur is likely to be SO2, or sulfur dioxide. The catalytic converter can change this into SO3 (sulfur trioxide), which then reacts with the catalyst to form sulfates on the catalyst. Over several minutes there is a build up of sulfates. If the engine suddenly starts to run rich (not enough air to burn all the fuel), such as when you stop at a red light, climb a steep hill, or brake hard to slow down, the chemistry changes. Now the sulfates are unstable and they react to form hydrogen sulfide, which is expelled from the exhaust pipe all at once. The high concentration is the reason for the bad smell!
07-18-14, 01:59 PM
#21
Sometimes the car automatically switch to circulation outside without your knowing. My IS350 did this all the times. Whenever I turn the AC on, it switch back to inside circulation. Whenever the circulation is outside, any smell outside will comes in to our car and when you accelerate hard, that air comes in even faster.
07-19-14, 07:17 PM
#24
check under all your mats to see if the carpet is wet...causing mildew smell...
if your a/c drain is clogged up, your carpet will get wet causing mildew smell...
this is what happened to me...
good luck
if your a/c drain is clogged up, your carpet will get wet causing mildew smell...
this is what happened to me...
good luck
07-23-14, 03:45 PM
#26
Rookie
Thread Starter
So I've changed the air cabin filter, no dice. Smell still doesn't occur when ac is on, whether it be on circulate or not. Smells with ac off, circulate or not. Guess I'll change the battery next. Been using chevron and shell premium for the past month. Any other brand of gas worth trying?
07-24-14, 10:41 AM
#28
Sorry to say, this thread is one of the most ridiculous and funny things I have ever encountered on Club Lexus forum.
I think your car is begging for a shower. Give it a full interior detail.
Finally, I would highly recommend this for a temporary fix. Buy a Ionic air purifier such as one below. It will neutralize odor. I have used this in my car.
do NOT buy those good smelling spray because it is not good for the body.
I think your car is begging for a shower. Give it a full interior detail.
Finally, I would highly recommend this for a temporary fix. Buy a Ionic air purifier such as one below. It will neutralize odor. I have used this in my car.
do NOT buy those good smelling spray because it is not good for the body.
09-02-14, 07:27 PM
#30
Rookie
Thread Starter
