Bad smell when engine rpms reach 3.5-4.5k

[JazzTrmpter]

Hey guys,

I have a 2005 v8 4Runner with just about 60k miles. I haven't done my 60k service yet, but I've been having this problem for quite some time. Probably about 6-7 months.

If I step on the accelerator and get the engine going around 3.5-4.5k rpms, a smell comes in the cabin (probably through the air vents) that doesn't smell good. It almost smells like a burning chemical - if you've ever worked in a photo processing lab, it smells like the silver recovery fluid from the developer machine's chemicals. It almost smells like an acid that tickles your nose. It's a very unique smell, so I can't describe it other than that.

I'm not sure if I'm burning oil; I've only ever put organic oil since I've had it (bought it at 33k miles almost three years ago). Exhaust isn't smoking or anything, this thing is running great. I'm just worried that something's wrong inside when it's really pulling. This is in Vegas where summer driving conditions are over 100 degrees every day of the week, and I can't remember if this happens in the winter. There are no abnormal noises while it pulls hard either. Just that bad smell.

This is just an intro post to kind of get some ideas on things I should check. I want to figure it out this week, I do maintenance myself. I'm about due for an oil change this week, so I'll change that and check my spark plugs for indication to see if oil is in fact burning and getting into places where it shouldn't be. It makes sense to me that something has gotta be burning, since I only smell this when the engine is generating more heat by moving faster.

Anyways, I'm not driving it much since I bought a motorcycle, but I don't want to put this off anymore. Thanks for your input!

 

[DC runner]

That would be the sulfuric oxidation coming from your catalytic converter. 3.5 to 4.5k, your flooring that engine.
Under those aggressive acceleration scenario's, then yea, you are smelling exhaust.

Nothing big. Short term. 1. Set vents to cabin
Long term, you can re-locate the exhaust to the side.

Finally.. TOTALLY NORMAL!!!! I say that because there are some insane myths running around. Sulfur smell is a normal by product of the catalytic converter.

 

[Shift-E-Eyes]

I believe there is a TSB on this if under 120k ( don't quote me on km's):

Exhaust system: If there is an excessive sulfur odor from the exhaust, the PCM (engine computer) will be reprogrammed and the catalytic converter replaced under the emissions warranty. (2003-05)

 

[JazzTrmpter]

That would be the sulfuric oxidation coming from your catalytic converter. 3.5 to 4.5k, your flooring that engine.
Under those aggressive acceleration scenario's, then yea, you are smelling exhaust.

Nothing big. Short term. 1. Set vents to cabin
Long term, you can re-locate the exhaust to the side.

Finally.. TOTALLY NORMAL!!!! I say that because there are some insane myths running around. Sulfur smell is a normal by product of the catalytic converter.

That's interesting! Is that suggesting that my car's exhaust system coming off the engine block is not completely sealed? The way I would imagine it is that my pipes are sealed all the way from my engine to the tip of my exhaust pipe in the rear.

Or, another possibility; is the engine putting out too much exhaust for the catalytic converter to handle all at once? That might explain why I only smell it at high RPMs, correct?

 

[rebelbowtie]

Do you drive with the back window down?

 

[JazzTrmpter]

I believe there is a TSB on this if under 120k ( don't quote me on km's):

Exhaust system: If there is an excessive sulfur odor from the exhaust, the PCM (engine computer) will be reprogrammed and the catalytic converter replaced under the emissions warranty. (2003-05)

In KM's I guess I'd be right up around 100K, or 62k miles. I haven't heard of an emissions warranty before. I know that I do not have any warranty on my vehicle though.

 

[JazzTrmpter]

Do you drive with the back window down?

Sometimes I do drive with the rear window cracked about 4-5 inches because I have a couple subwoofers that rattle the rear door silly. With the window cracked that far it seems to eliminate most of the rattling.

Now that you mention it, I'll take a test to see if I can smell anything while driving at city/highway speeds with the window all the way up. Good point, since I have smelled exhaust at lower speeds with the rear window down.

 

[DC runner]

1. My read is the TSB had very little impact. It was mainly a response to people *****ing. Similar to the gas pedal TSB. People with 5th gens and other models continue to moan. The smell is a totally normal by product. Getting rid of it shouldn't be a goal. You can reduce you chance to smell it by relocating the exhaust tip.

2. The v8 is pretty notorious for cracking the exhaust manifold. I have a slight crack on mine. If you regularly crank that engine to 4.5k, then I would imagine you have had more extreme hot/cold cycles on your exhaust manifold. It is the metal heat expansion cycle that causes the manifold cracks...

The V8 does have both first stage cats really close to the engine bay. You can SEE it, so a leak in the exhaust around that area would def. come back up.

3. The rear window does pull it in. I only ever smell the exhaust when I am driving with the rear down and under heavy load. Either up a steep hill, or putting the pedal down to pass. Under lite load I never smell it.


Anyway. Yea, I wouldn't be worried. Totally normal. If you can pinpoint the conditions that happen to have you smell it, you can work from there and fix it. I always drive with it on RECIRC and have never smelled it from the vents. You could try that and see if that helps.

 

[Shift-E-Eyes]

Found the 2006 TSB

And the 03-04

 

[JazzTrmpter]

Found the 2006 TSB

And the 03-04

Wow, you took a screenshot on your iPhone! Thanks for your dedication. So, based on the picture for the '06, my vehicle is covered under this emissions warranty? Says up to 80k miles after toyota service, I'm at ~62k.

 

[Gumps_runner]

It helps a lot to keep your back window up, I rarely smell it when the window is up. If the rear window is just cracked a bit it will smell every time you pin the gas pedal.

 

[DC runner]

I consider the fact that Toyota released multiple TSB's, the first coming out in 2003 and the second in 2006 as evidence that it is normal and they "release" a fix every now and then to shut people up.

Otherwise, why wouldn't they have actually "solved" it in the 04, 05, 06 and later models?

I just did a google search and the 5th gens are complaining..
this is an issue of education. The smell is a normal by product.