Air filter restriction causes sulfur smell??

[Fro-Runner]

I was driving on the freeway today with my back window partially opened only to be almost smogged out of the truck. I accelerated hard to pass some vehicles when this awful sulfuric smell entered my truck cabin. Funny thing is that I've already had both the cat back TSB and the ECU reprom done but this thing still smells bad.

Here's my analysis of what may be causing this problem with the V-6 4 Runners. Toyota worked really hard to get this vehicle to pass the strict NY and CA emissions with a LEV rating. If you have changed your air filter or if you care to just go out and take a look; you will see what appears to be a second filter just beyond the regular air filer.
It's in the main air cleaner housing just beyond the disposable air filter. You can touch it with you finger. I actually thought it was the real filter until I tried to pull it out and it wouldn't move.

Now I've had other vehicles before and a good mechanic knows that when a vehicle is running too rich/lean it causes a rotten egg odor to come from the tailpipe. I'd be willing to bet that this V-6 engine is being starved of its air flow thus creating this smell. This is also why the Toyota dealers continue tell us that it is the brand of gas we are using because some states allow more sulfur in their gas. This along with the incorrect air/fuel ratio causes a more stinky smell when you accel thus allowing for more unburnt fuel/carbons/etc.

I wrote this message to see if any of you members with a garage would be willing to explore this supposely second air fliter restriction inside of the main air cleaner to see if it is removeable. I do not have a garage and will be out of town till monday. It would be much appreciated if some of the more adventurous members would explore the air cleaner area to see if we can solve the issue since Toyota doesn't seem to give a crap. Thanks!

 

[toyota03]

I was driving on the freeway today with my back window partially opened only to be almost smogged out of the truck. I accelerated hard to pass some vehicles when this awful sulfuric smell entered my truck cabin. Funny thing is that I've already had both the cat back TSB and the ECU reprom done but this thing still smells bad.

Here's my analysis of what may be causing this problem with the V-6 4 Runners. Toyota worked really hard to get this vehicle to pass the strict NY and CA emissions with a LEV rating. If you have changed your air filter or if you care to just go out and take a look; you will see what appears to be a second filter just beyond the regular air filer.
It's in the main air cleaner housing just beyond the disposable air filter. You can touch it with you finger. I actually thought it was the real filter until I tried to pull it out and it wouldn't move.

Now I've had other vehicles before and a good mechanic knows that when a vehicle is running too rich/lean it causes a rotten egg odor to come from the tailpipe. I'd be willing to bet that this V-6 engine is being starved of its air flow thus creating this smell. This is also why the Toyota dealers continue tell us that it is the brand of gas we are using because some states allow more sulfur in their gas. This along with the incorrect air/fuel ratio causes a more stinky smell when you accel thus allowing for more unburnt fuel/carbons/etc.

I wrote this message to see if any of you members with a garage would be willing to explore this supposely second air fliter restriction inside of the main air cleaner to see if it is removeable. I do not have a garage and will be out of town till monday. It would be much appreciated if some of the more adventurous members would explore the air cleaner area to see if we can solve the issue since Toyota doesn't seem to give a crap. Thanks!

HMMMMMMMM!!!!!!! :bigok:

 

[Uneek]

The filter is removable. I've read a few 2005+ Tacoma owners over on ToyotaNation.com have removed theirs.

 

[Fro-Runner]

The filter is removable. I've read a few 2005+ Tacoma owners over on ToyotaNation.com have removed theirs.

Thanks sir! The website was very informative about that secondary filter. I will probably remove mine tommorrow and save if for a reinstalled just before my first smog session.

 

[msanta]

I still smell it a little less even after replacing the stock air intake with a Volant CAI. I don't know if this helps you?

 

[Fro-Runner]

I just do not understand why it smells so badly on the 4Runner. None of the Tacoma drivers have complained like we have about this digusting smell. It so bad at times that I look in my rearview mirrors and see cars actually lagging behind to avoid my stinky Runner's booty. I have to try something because the smell stinks. I even purchased another chrome tip that pointed downward toward the ground to see if the smell decreased but to no avail. I do believe that curving the exhaust pipe of to the side (like the Tacoma's) would help resolve the smell coming up the back window and into the truck.

Funny how that big ole, fat spoiler suppose to create all of this down force to keep the rear window clear of debris yet it seems to aid in driving the sulfuric smell right into your truck!

 

[snap315]

One possible reason that Tacoma drivers haven't complained as much as 4Runner owners is that they don't have a power rear window at the very rear end of their vehicles.

With our T4R's, we smell the exhaust at it's worst.

And before I had my TSB done (which actually solved my Sulfur smell problem), I too noticed other drivers hanging back to avoid my smelly truck. It was damn shameful and one of the main reason i got the TSB done! :bash:

 

[jharris2]

I too noticed other drivers hanging back to avoid my smelly truck. It was damn shameful and one of the main reason i got the TSB done! :bash:

Or use it as a way to avoid getting rear-ended.

 

[Baba Booey]

I use it as a means to punish those drivers who ride to close to my bumper. A quick stomp on the throttle and I let them wallow in my smelly exhaust.

 

[jeober]

Hi,

Your air/fuel ratio is precisely controlled by oxygen sensor feedback. Intake restriction has no bearing on this. The second (carbon) filter, that adsorbs unburned hydro-carbon (vapors) during vehicle off, has no impact on the exhaust emissions (including the sulfur smell).

I have 9 patents in Fuel Systems and 28 years of automotive engineering experience. I may not be always right but have some experience here.

 

[pickerdd]

Sorry if this is a silly question, but are we sure this isn't related (at least in part) to the quality of gasoline we're burning? I know that there are issues with the Catalytic converters, but what about the quality of the gasoline we're using?

Now that we have nice weather in Atlanta, I've been driving my 4R with the back window and sunroof open. I have smelled the sulfur smell once or twice, but I mostly smell an ammonia smell. Anyway, I'm wondering if the smell is related to poor quality gasoline? I usually fill up my truck at Quick Trip or my local Shell station, but also on occasion fill up at a local RaceTrack gas station.

Any thoughts?

David

 

[Mr. Lambdebois]

Hi,

Your air/fuel ratio is precisely controlled by oxygen sensor feedback. Intake restriction has no bearing on this. \

I have 9 patents in Fuel Systems and 28 years of automotive engineering experience. I may not be always right but have some experience here.

Very impressive resume. Maybe you could clear a few things up for me...

That makes sence of a reactive system but from my understanding on a predictive sytem like most newer vehicles A/F is innitally controled by things like.....
engine load/throttle position
mass air flow signal
and some other inputs and then the oxygen sensors measure and compare specs to values in the ROM. The ECU can then make adjustments but if you floor it the ecu will go right back to looking at other inputs and preplanned tables for the value's of how much fuel to give and then use the oxygen sensor for feedback to make adjustments.

 

[greasefingers]

That

 

[greasefingers]

Also the upstream O2 sensors are the control inputs to the ECU. The downstream ones have no performance contributions. They do however tell you when the catalysts are spent. This is done by comparing the upstream & downstream valves. The downstream oxygen content should be very low compared to the upstream ones if the catalyst converted the nasty inlet gases to less nasty ones. If the valves are the same then the Cat need replacing.

 

[Fro-Runner]

Hi,

Your air/fuel ratio is precisely controlled by oxygen sensor feedback. Intake restriction has no bearing on this. The second (carbon) filter, that adsorbs unburned hydro-carbon (vapors) during vehicle off, has no impact on the exhaust emissions (including the sulfur smell).

I have 9 patents in Fuel Systems and 28 years of automotive engineering experience. I may not be always right but have some experience here.

Ok, then if you are right......why is this carbon cahrcol filter permenantly mounted inside the vehicle's air cleaner housing? This makes very little sense to me for the following reasons. First off, this charcol filter will GET DIRTY! The weak stock filter was dirty when I replaced it at 15k miles.

Secondly, this charcol air filter (I call it an air filter because it sits between the air intake hose and the engine's main breathing component--throttle body) would seem to restrict the air flow when it becomes dirty.....and it WILL!

Third, knowing how Toyota loves to take our money with thier maintainence departments, why isn't this part as replaceable as the air filter itself. At the very least, the charcol filter should be replaced every second time the normal air filter is replaced. You, everyone and myself knows that a clogged, dirty air fliter robs an engine of its power!

Lastly, why do people install the more free flow cold intake filters (K&N, Volant, etc)? Hmmm, let me think........to get much more air flowing into the engine!

Now taking the above facts into account, why is this charcol filter semi permanently mounted in this way as not to be changed by the buyer to ensure a fresh, maximum air flow into the throttle body area? I'm thinking CA/NY/MA state emissions requires it to be installed to meet thier specifications. But why does Toyota not mention this filter in the vehicle's service manual? Why is it not recommended to bring the vehicle into the service department for a charcol filter change at the very minumum of every 15k-20k mile intervals. Better yet, give the buyer the option of self maintanence for this part.

I live in southern Califunky where newer automobiles and trucks are a norm. It intrigues me that no other newer vehicle's exhaust smells like a rotten egg when I'm following them on the freeway. When I run my HVAC in free flow mode on our busy freeways, I do NOT smell rotten egg odors coming from BMWs, Audis, Lexus, Honda, Nissians, Chevys or even a ragged Ford. Now you tell me....... there has to be a problem which Toyota can NOT afford to address without compromising this vehicle's emissions rating.

In short..... a rotten egg exhaust smell means that something is wrong with a vehicle's air fuel mixture/combustion procedure. The Toyota corporation should get this right now...... before later.

 

[Mr. Lambdebois]

Wow. I had to take my mastiff somewhere today and put down the back window. As you guys have all been complaining about some stinky stuff. When I really got on it is was a really strong odor of amonia mixed the sulfer. Never really had the widow down and noticed it before untill today but it was a awfull smell.
Now I know why you all are complaining so bad.



What is the tsb for an 06 4runner on this?

 

[Fro-Runner]

Every 4Runner owner should roll his rear window down halfway and then go accelerate on a freeway on ramp. He/she will not like the air quality within the truck's cabin after doing so---I guarantee you!

This stuff stinks almost as bad as a skunk's piss.

I should add that I only use top tier 1 gasoline such as Cheveron, Exxon, Shell, etc. It is not the gas......it's something this Toyota engine is not doing correctly with the air/fuel ratio mixture!

 

[greasefingers]

I believe the charcoal filter is there so that the emissions can be certified as LEV-II, or it is one of many requirements that is needed to meet that specification.

Charcoal absorbs petrol vapors after shut down so that they do not escape to the atmosphere. The gas tank vapour recovery system works the same way where a charcoal canister does this very same function to the head-space vapors in the gas tank, which introduced into the intake manifold.

The charcoal filter should not get dirty since it is downstream of the paper air filter. I do not believe charcoal filter is a restriction (huge particle size is used)

I am also not a believer that the paper filter restricts any significant air either.

I do not know enough about catalysts to comment on the sulfur smell. But I would not assume that it is an indication that something is wrong. It could be the type of catalysts used, meaning that a stinky component is not being converted to something that is less stinky?