Rotten Egg smell from "spirited" acceleration
11-15-18, 10:16 AM
#1
Advanced
Thread Starter
Rotten Egg smell from "spirited" acceleration
Hello,
I have a 04 LS with 79K. Sometimes with moderate acceleration to around 3K rpm there is a rotten egg smell from the exhaust. I smell it really bad if the driver's window is down. Anyone else experience is this, maybe a bad cat? No CEL or any drivability issues.
I have a 04 LS with 79K. Sometimes with moderate acceleration to around 3K rpm there is a rotten egg smell from the exhaust. I smell it really bad if the driver's window is down. Anyone else experience is this, maybe a bad cat? No CEL or any drivability issues.
11-15-18, 10:20 AM
#2
It could well be a cat going bad.
11-15-18, 11:24 AM
#3
Instructor
The official Lexus TSBs about this say to try changing where you get your gas from. Although I've always used Top Tier fuels, I think I have this issue sometimes too. The reason I'm not totally sure is because the smell could be from adjacent vehicles. Doesn't happen often enough for me to be sure that it's my car.
11-15-18, 01:41 PM
#4
The rotten egg smell is a sulphur compound. I'm with VanDam and think it is probably bad gas- I use Shell premium unleaded (top tier) and I have never smelled anything unusual.
11-15-18, 03:10 PM
#5
Intermediate
I say bs to bad gas. I had an 01 that would do this every time. I now have an 06 and use the same exact fuel stations. Sams Club, Meijer premium and no sulphur smell. Dont quote me but I heard O2 sensors that are old can do this, even if there is no check engine light. You should be able to see the O2 values on a scanner to see if the cat is working well or just on the edge.
Also, if youre smelling it inside the car, theres probably an exhaust leak somewhere closer to the Y pipe or manifolds.
Does your car tick on cold startups?
Also, if youre smelling it inside the car, theres probably an exhaust leak somewhere closer to the Y pipe or manifolds.
Does your car tick on cold startups?
Last edited by RushNatU; 11-15-18 at 03:18 PM.
11-15-18, 11:54 PM
#6
Another thing I would check is the fuel pressure pulsation dampers...there are 2 on this car...I have had to replace both of mine in the last year, but the leak starts slow and you can smell gas.
Also...I found that the fuel you used wouldn't make much of a difference. I tried 91 and 94 but honestly it is the CAT that is your problem IMO. I always use 94 now...the higher the better with this car.
11-28-18, 08:37 PM
#7
Driver School Candidate
Rotten egg smell after spirited driving is your catalytic converter(s) doing their job. Do not worry about it. If you want this smell to go away, don't drive aggressively or just drive more spirited more often. Something tells me this car has never been driven hard in its lifetime. When you use more power, you are using the catalytic converters more. That's the smell good, working catalytic converters produce doing their job. Roll up the windows and turn on the a/c and enjoy the performance. Or put the top down and slow down and smell the roses. Your car is fine and working properly.
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11-28-18, 09:15 PM
#8
Instructor
From my post in another related thread, the sulfur smell can be normal if it doesn't happen all the time.
Source: https://web.archive.org/web/20081121...t/catalyst.htm
If the smell happens all the time, you have a problem. The causes are one or more of the following:
* Bad battery - https://www.pe.com/2011/07/03/stinky...a-bad-battery/ - If a battery is frozen, overcharged, or has otherwise shorted out internally, it may cause the case to vent gas. It is important to have your vehicle inspected as soon as possible, as the sulfuric acid in batteries can cause corrosion or eat away at other vital engine parts.
* You have been driving your car slowly and gingerly for a while, and then you put the petal to the metal to pass someone, which heats up the catalytic converter and burns the deposits of sulphur and hydrocarbons that have built up over the last few weeks. If you rarely push the revs when you are driving, there will be a larger buildup of sulfates on the catalyst for when you gun it to pass someone on the highway, which heats up the catalytic converter and it burns off. Pro tip: Once a week drive your car like a teenager.
* High sulfur fuel. California and European fuel has less sulfur than other places. Lexus will refer you to a TSB just like Buick did here - https://www.groovecar.com/articles/a...doing-its-job/ - The rotten egg smell is from the catalytic converter working to clean the exhaust. Replacing the catalytic converter will not eliminate the 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. Dealers will tell you to switch to a different brand of fuel and drive the vehicle for at least 100 miles. It can take five fill ups to clean out the smell from a catalytic converter. Run the gas tank down to just under 1/4, switch the brand and gasoline grade to a higher octane. The higher the octane, the hotter and cleaner the gas burns.
* Caused by a failing catalytic converter. Hydrogen sulfide, found in the exhaust, is produced by a touch of sulfur in fuel. Once it enters the catalytic converter, it should convert to sulfur dioxide. It is true that using a different gasoline brand can sometimes lessen the smell. Driving on the highway can also help eliminate it. Driving habits do contribute to the intensity of the smell. It seems the more local driving, the more the catalytic converter builds up chemicals that give the smell. There are some expensive catalytic converter cleaners that may help and if the smell bothers you this much, then I would recommend trying a couple of applications.
* Cracks in the exhaust manifold can cause the smell - https://www.consumerreports.org/car-...exhaust-leaks/ - One owner of a 2017 Explorer said in the survey, “If you accelerate over 3,500 rpm, the cabin smells like rotten eggs” An owner of a 2016 Explorer noted, “Vehicle gets exhaust smell through A/C into cabin when hard-accelerating.”
* A fuel injector that doesn't close precisely when it should (stays open too long) causes the fuel mixture to be too rich, causing the cats to overheat and causes this smell. When the catalytic converter isn't able to convert all of the fuel, you get excessive sulphur dioxide emissions - and that rotten egg smell. You'll then soon be facing a plugged and inoperable catalytic converter. This occurs because the reactions inside the cat create heat, and if it is not controlled under normal operating conditions, the heat will reach a point that will melt the substrates that make up the interior reaction elements of the cat.
* Clogged cats can overheat and cause this smell. If left to the point of plugging, the exhaust gases and heat can't leave the engine, which will eventually lead to internal damage to the engine - on top of the damage to the catalytic converter. Someone on these forums posted a few months ago a picture of some strange debris in the cats, don't think anyone had a guess as to where that debris came from, but it definitely blocked airflow.
* One of the sensors on the car that has to do with fuel management is not doing its job, so the engine is injecting too much fuel and running rich. The catalytic converter is not able to effectively process the byproducts of the exhaust when this happens. When the catalytic converter is overwhelmed from running rich for too long, these byproducts are sent out the tailpipe unprocessed and they have a very distinct smell. Another symptom of a bad sensor is that too many byproducts in the catalytic converter makes it run very hot, burning off all of its buildup, which can cause a very strong odour
* Plug in TechStream or any OBD2 scanner, check your short-term and long-term fuel trims to see if you are regularly running rich, and also check your O2 sensor voltage waveforms to ensure correct sensor operation. O2S signal voltage must fluctuate above and below 0.45V at least 8 times in 10 seconds (0.8Hz) at 2500rpm with the engine at operating temperature. During the rich swing, voltage should exceed 550mV, and during the lean swing should fall below 400mV.
* Perform a rattle test on the cats - hit the converter shell with the center of your palm (don't hit it too hard or you may damage it!). If the substrate is OK, it should sound solid. If it rattles, you need a new cat.
* Perform a restricted exhaust system check: attach a vacuum gauge to an intake manifold vacuum source, with engine at operating temperature, hold revs at 2000rpm, ensure vacuum reading is close to normal idle, then quickly let go of the throttle. The vacuum reading should momentarily rise then smoothly drop to normal idle. If the vacuum rises slowly or does not quickly return to normal, the exhaust system may be restricted.
* Do not use any type of fuel additives, as this could add sulfur to the fuel and cause/increase the odor.
* Avoid short-trip driving and aggressive acceleration -- OR do only long-trip driving with aggressive acceleration to always keep the sulfates burned off.
It's 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! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
"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! This effect is a common problem with new vehicles because the catalyst is working at a very high efficiency. However, as the catalyst gets older, the activity drops. Fortunately for us, one of the first reactions to be affected is the formation of hydrogen sulfide. So as the catalyst gets older, the smell will go away. It should also be noted that many catalysts never smell bad. One reason might be because the vehicle doesn't run lean for much of the time, or perhaps the catalyst has an extra component that reduces the production of hydrogen sulfide.
If the smell happens all the time, you have a problem. The causes are one or more of the following:
* Bad battery - https://www.pe.com/2011/07/03/stinky...a-bad-battery/ - If a battery is frozen, overcharged, or has otherwise shorted out internally, it may cause the case to vent gas. It is important to have your vehicle inspected as soon as possible, as the sulfuric acid in batteries can cause corrosion or eat away at other vital engine parts.
* You have been driving your car slowly and gingerly for a while, and then you put the petal to the metal to pass someone, which heats up the catalytic converter and burns the deposits of sulphur and hydrocarbons that have built up over the last few weeks. If you rarely push the revs when you are driving, there will be a larger buildup of sulfates on the catalyst for when you gun it to pass someone on the highway, which heats up the catalytic converter and it burns off. Pro tip: Once a week drive your car like a teenager.
* High sulfur fuel. California and European fuel has less sulfur than other places. Lexus will refer you to a TSB just like Buick did here - https://www.groovecar.com/articles/a...doing-its-job/ - The rotten egg smell is from the catalytic converter working to clean the exhaust. Replacing the catalytic converter will not eliminate the 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. Dealers will tell you to switch to a different brand of fuel and drive the vehicle for at least 100 miles. It can take five fill ups to clean out the smell from a catalytic converter. Run the gas tank down to just under 1/4, switch the brand and gasoline grade to a higher octane. The higher the octane, the hotter and cleaner the gas burns.
* Caused by a failing catalytic converter. Hydrogen sulfide, found in the exhaust, is produced by a touch of sulfur in fuel. Once it enters the catalytic converter, it should convert to sulfur dioxide. It is true that using a different gasoline brand can sometimes lessen the smell. Driving on the highway can also help eliminate it. Driving habits do contribute to the intensity of the smell. It seems the more local driving, the more the catalytic converter builds up chemicals that give the smell. There are some expensive catalytic converter cleaners that may help and if the smell bothers you this much, then I would recommend trying a couple of applications.
* Cracks in the exhaust manifold can cause the smell - https://www.consumerreports.org/car-...exhaust-leaks/ - One owner of a 2017 Explorer said in the survey, “If you accelerate over 3,500 rpm, the cabin smells like rotten eggs” An owner of a 2016 Explorer noted, “Vehicle gets exhaust smell through A/C into cabin when hard-accelerating.”
* A fuel injector that doesn't close precisely when it should (stays open too long) causes the fuel mixture to be too rich, causing the cats to overheat and causes this smell. When the catalytic converter isn't able to convert all of the fuel, you get excessive sulphur dioxide emissions - and that rotten egg smell. You'll then soon be facing a plugged and inoperable catalytic converter. This occurs because the reactions inside the cat create heat, and if it is not controlled under normal operating conditions, the heat will reach a point that will melt the substrates that make up the interior reaction elements of the cat.
* Clogged cats can overheat and cause this smell. If left to the point of plugging, the exhaust gases and heat can't leave the engine, which will eventually lead to internal damage to the engine - on top of the damage to the catalytic converter. Someone on these forums posted a few months ago a picture of some strange debris in the cats, don't think anyone had a guess as to where that debris came from, but it definitely blocked airflow.
* One of the sensors on the car that has to do with fuel management is not doing its job, so the engine is injecting too much fuel and running rich. The catalytic converter is not able to effectively process the byproducts of the exhaust when this happens. When the catalytic converter is overwhelmed from running rich for too long, these byproducts are sent out the tailpipe unprocessed and they have a very distinct smell. Another symptom of a bad sensor is that too many byproducts in the catalytic converter makes it run very hot, burning off all of its buildup, which can cause a very strong odour
* Plug in TechStream or any OBD2 scanner, check your short-term and long-term fuel trims to see if you are regularly running rich, and also check your O2 sensor voltage waveforms to ensure correct sensor operation. O2S signal voltage must fluctuate above and below 0.45V at least 8 times in 10 seconds (0.8Hz) at 2500rpm with the engine at operating temperature. During the rich swing, voltage should exceed 550mV, and during the lean swing should fall below 400mV.
* Perform a rattle test on the cats - hit the converter shell with the center of your palm (don't hit it too hard or you may damage it!). If the substrate is OK, it should sound solid. If it rattles, you need a new cat.
* Perform a restricted exhaust system check: attach a vacuum gauge to an intake manifold vacuum source, with engine at operating temperature, hold revs at 2000rpm, ensure vacuum reading is close to normal idle, then quickly let go of the throttle. The vacuum reading should momentarily rise then smoothly drop to normal idle. If the vacuum rises slowly or does not quickly return to normal, the exhaust system may be restricted.
* Do not use any type of fuel additives, as this could add sulfur to the fuel and cause/increase the odor.
* Avoid short-trip driving and aggressive acceleration -- OR do only long-trip driving with aggressive acceleration to always keep the sulfates burned off.
Last edited by StanVanDam; 09-25-22 at 11:34 AM.
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