Strong Exhaust Smell

[syndicate]

Hey guys, I've been lurking for a while and decided to register and ask a question, hopefully it hasn't been asked every other day.


There is a strong exhaust smell that come in when the rear glass is down. Is this normal for 3rd gens or do I need to replace some exhaust components?

 

[BlackCat914]

ya, pretty normal. I typically notice mine when I'm slowing to a stop. It's worse if I'm pulling my ATV and trailer.

 

[syndicate]

Ok thanks. It doesn't really bother me but the wife can't stand it.

 

[BlackCat914]

Ok thanks. It doesn't really bother me but the wife can't stand it.

get a new wife.

 

[syndicate]

get a new wife.

Cheaper to keep her at this point.

 

[BlackCat914]

Cheaper to keep her at this point.

haha, nice!

 

[MONTYMTB]

Cheaper to keep her at this point.

Old joke: "My wife's credit card was stolen, but I didn't report it because they were spending less than she was!"

 

[BoarderDave]

Side bar on this topic... does anyone know WHY they do this if this is common?
I have the same thing.. and its always in the back of my mind. And my wife also thinks its strange.

What causes it? Mine seems to only be on cold startup. Once at operating temp, I don't smell anything off. But for the first few minutes of driving.. smells like its running rich or something. :yawn:

 

[3rzrunner]

Side bar on this topic... does anyone know WHY they do this if this is common?
I have the same thing.. and its always in the back of my mind. And my wife also thinks its strange.

What causes it? Mine seems to only be on cold startup. Once at operating temp, I don't smell anything off. But for the first few minutes of driving.. smells like its running rich or something. :yawn:

the cat on start-up is cold so it is not as effective as when warm, after a few mins the cat(s) warm up to their optimum temp. and reduce the smell of gas.

 

[Kanger328]

Is it worse then you're used to? I also had this issue, but felt the smell got a lot worse. Found out I had a crack in my exhaust pipe just before the cat.

 

[BlackCat914]

the cat on start-up is cold so it is not as effective as when warm, after a few mins the cat(s) warm up to their optimum temp. and reduce the smell of gas.

Sort of. A cold engine is still in closed loop and doesn't take air fuel samples from the a/f sensor, and a cold engine requires more fuel. They run rich when cold.

 

[BoarderDave]

the cat on start-up is cold so it is not as effective as when warm, after a few mins the cat(s) warm up to their optimum temp. and reduce the smell of gas.

Sort of. A cold engine is still in closed loop and doesn't take air fuel samples from the a/f sensor, and a cold engine requires more fuel. They run rich when cold.

Thanks for the information on this. Is there any remedy to get it to run a little less rich when cold? Or is that just the way its designed and that's what it always will be?

I mean, I know in general vehicles run that way to effectively reach operating temperature, but this is the first vehicle I have owned that I can actually smell the difference on. Which is what made me think there was something wrong in the first place.

Thanks y'all. Good to have some additional insight on this.

 

[BlackCat914]

Thanks for the information on this. Is there any remedy to get it to run a little less rich when cold? Or is that just the way its designed and that's what it always will be?

I mean, I know in general vehicles run that way to effectively reach operating temperature, but this is the first vehicle I have owned that I can actually smell the difference on. Which is what made me think there was something wrong in the first place.

Thanks y'all. Good to have some additional insight on this.

you could find a tuner and lean it out a bit during closed loop operation, but you may have driveability issues as a result.

 

[mistercmason]

My 3RZ does the same thing on long uphill 4th gear pulls. Smells like sewage

 

[BoarderDave]

you could find a tuner and lean it out a bit during closed loop operation, but you may have driveability issues as a result.

Yeah, I wouldn't want to go through all the trouble of trying to make the computer think something different. I'm sure Toyota put their time and energy into building logic into their computer the right way. :nod: I was just curious..
Thanks for the help.

 

[02SE]

Sort of. A cold engine is still in closed loop and doesn't take air fuel samples from the a/f sensor, and a cold engine requires more fuel. They run rich when cold.

Should read "Open Loop".

 

[pluton]

I mean, I know in general vehicles run that way to effectively reach operating temperature, but this is the first vehicle I have owned that I can actually smell the difference on. Which is what made me think there was something wrong in the first place.

The thing wrong is driving with the tail window open...the airflow around the rear of the vehicle basically pumps exhaust into the cabin under normal conditions.
The main reason engines run rich when cold is so that they'll start and run, period. On carbeuretted engines they had this thing called the choke, which cut the air quantity in the mixture, and enabled easy starting and cold running. Now, a computer does it.
If you hang out next to the exhaust(not recommended), even the low emission gas vehicles have a thicker, more chemical-smelling exhaust when first started cold than when they're warmed up.

 

[BlackCat914]

Should read "Open Loop".

yup, you're right. Brain fart moment. :wacko:


I started a car cold in the shop to show values. in OPEN ( :naughty: ) loop, 02 sensors aren't even switched on.

 

[1985taylor1925]

I have the same issue as op. Have written about it a few times in the past as I didn't know what it was and was concerned it might be something serious. Mine is REALLY bad when pulling to a stop with windows down after Ive been driving at roughly 55 or faster. I never smell it around the truck after starting it. Only after driving with rpms up for a while.

I read the rotten eggs/gassy smell is a result of the cat wearing out. Is this true?

 

[Brique]

The odd thing to me is that i didn't get the open loop stink with my Tacoma. Same 3.4l (1998), but the smell when starting cold is one of the first things i noticed when i sold the taco and bought the t4r.