Nasty smell after accelerating

[Nick1994]

This is on my aunt's 16' Toyota Avalon, 66k miles. For 2-1/2 to 3 years it has made a nasty rotten egg sulfur smell after a hard acceleration. Nauseating, it gases you out and you've got to roll all the windows down for 5 minutes after to make it somewhat habitable. If you drive the car like an old lady, it's fine. Merging into the carpool lane, a fast highway on-ramp, or climbing the hills is what triggers it. 2-1/2 years ago we took it out of town to visit family and were gassed out. That was the last time it left the city, we always take my car or ride with someone else since then. When it was new we took it on a 2 week, 9 state, 5,000 mile road trip with 5 national parks. No smells. Plenty of full throttle runs.

We took it to the dealer 2-1/2 years ago and they thought it was the battery (it was leaking) so they replaced it. That didn't make a difference. Not wanting to deal with the dealer, she hasn't taken it back until last week. They can't find anything wrong, no pending codes, nothing under the car that's burning etc. They keep saying all they see that causes smells is bad batteries, but I replaced it last week because it died (AZ heat).

I think it's a bad catalytic converter, but the dealer says it can't be bad without a CEL . They said they can't do more diagnostic unless she paid by the hour for them to keep looking.

Car also has an extended warranty until 120k miles, but I don't know that it will cover emissions equipment (if that is the problem).

Any ideas?

 

[AutoMechanic]

It also sounds like a bad catalytic converter to me as well. That’s happened on a few of the ones I’ve seen go bad. Could be clogged as well. What happens is the unburnt gas gathers in the exhaust and causes the smell.

 

[dishdude]

Oh I know that smell. I think you're right on it being the cat. Seafoam it!

 

[oldhp]

The smell is the cat getting hot and burning out the crud. The bigger problem is why do you get the smell in the car???? Exhaust leaking??? HVAC system leaking??? Somethings not right.

 

[01rangerxl]

Bad sulphur fart smell from late model Toyotas, especially FWD vehicles, is pretty common. There's one hill here on hwy 11 by St Vincent's East medical center where if you are behind a Rav4 or Highlander, you will get gassed.

 

[Chris142]

Has to have an exhaust leak after the cat. Put a rag against the tailpipe and find it.

 

[Egg_Head]

Does this only occur when your aunt is in the car?

 

[Lubener]

A converter should never go bad in 66k miles unless it is a victim of a poorly running engine. In your case, I think it's doing its job trying to deal with a rich running engine.

 

[wag123]

My Sienna has done this since day one. My wife's Honda does it too. It only happens after moderate to hard acceleration before the engine is completely warmed-up. It is caused by a rich running condition during open-loop mode. It never occurs after the engines are fully warmed-up and operating in closed-loop mode or if the cars are driven gently during the warm-up period.

 

[spasm3]

My Sienna has done this since day one. My wife's Honda does it too. It only happens after moderate to hard acceleration before the engine is completely warmed-up. It is caused by a rich running condition during open-loop mode. It never occurs after the engines are fully warmed-up and operating in closed-loop mode or if the cars are driven gently during the warm-up period.

I wonder if the thermostat is working?
Could it be stuck open or partially open, an running a bit cold?

 

[supton]

Is it the gas blend in your area? now that you mention it, I remember smelling that often, and knowing it was a Toyota, but I haven’t smelled it in a while. Maybe low sulphur gas in this area is really low sulphur?

 

[Rand]

pentastars do this on full throttle too.. noticed plenty of fords do same thing.

 

[dblshock]

buddys new at the time '05 Maxima same thing even on a warm engine never found the source.

 

[Jim K]

Nasty Smell ? Check to see if you have a gas leak from your rear end.

 

[gregk24]

I have noticed this when driving be hind some Toyota/Lexus products. I think it may be normal operation.

 

[JTK]

Bad sulphur fart smell from late model Toyotas, especially FWD vehicles, is pretty common. There's one hill here on hwy 11 by St Vincent's East medical center where if you are behind a Rav4 or Highlander, you will get gassed.

Agree.

I live in a very hilly area and if you are beyond a late model Toyota, you will get sulfur bombed. IMO, it's normal catalyst behavior with Toyota's fuel mapping.

The OP has exhaust leaking into the cabin. My guess is the rubber flap vents in the rear corners of the vehicle. They're probably under the rear bumper cover. Sometimes the flaps (check valves) fall off.

 

[hemitom]

This is on my aunt's 16' Toyota Avalon, 66k miles. For 2-1/2 to 3 years it has made a nasty rotten egg sulfur smell after a hard acceleration. Nauseating, it gases you out and you've got to roll all the windows down for 5 minutes after to make it somewhat habitable. If you drive the car like an old lady, it's fine. Merging into the carpool lane, a fast highway on-ramp, or climbing the hills is what triggers it. 2-1/2 years ago we took it out of town to visit family and were gassed out. That was the last time it left the city, we always take my car or ride with someone else since then. When it was new we took it on a 2 week, 9 state, 5,000 mile road trip with 5 national parks. No smells. Plenty of full throttle runs.

We took it to the dealer 2-1/2 years ago and they thought it was the battery (it was leaking) so they replaced it. That didn't make a difference. Not wanting to deal with the dealer, she hasn't taken it back until last week. They can't find anything wrong, no pending codes, nothing under the car that's burning etc. They keep saying all they see that causes smells is bad batteries, but I replaced it last week because it died (AZ heat).

I think it's a bad catalytic converter, but the dealer says it can't be bad without a CEL . They said they can't do more diagnostic unless she paid by the hour for them to keep looking.

Car also has an extended warranty until 120k miles, but I don't know that it will cover emissions equipment (if that is the problem).

Any ideas?

Some of the problem may be short trips in the car and not getting the cats up to temp often enough ?
so when get it on the highway it is getting hot and cleaning itself out .
on a side note merged onto the highway yesterday behind a fairly new cx5 , as they got on the gas to merge an extremely large cloud of grey gas smelling exhaust bellowed out ,it cleared up right away ,as i followed him for a few miles no smoke no smell after that.

 

[OVERKILL]

The smell is the cat getting hot and burning out the crud. The bigger problem is why do you get the smell in the car???? Exhaust leaking??? HVAC system leaking??? Somethings not right.

This is what immediately crossed my mind as well. While the rotten egg smell isn't uncommon, you shouldn't be smelling it in the car if it is coming from the exhaust, as that means the exhaust is coming in the car.

 

[Dave9]

This is normal and expected, not a fault on many vehicles, except to smell it strongly in the cabin may mean an undercarriage leak.

The effects of the catalytic converter and fuel sulfur level on motor vehicle particulate matter emissions: gasoline vehicles - PubMed

Scanning mobility and electrical low-pressure impactor particle size measurements conducted during chassis dynamometer testing reveal that neither the catalytic converter nor the fuel sulfur content has a significant effect on gasoline vehicle tailpipe particulate matter (PM) emissions. For...

pubmed.ncbi.nlm.nih.gov

a sulfur balance is not obtained over the drive cycle. Instead, sulfur is stored on the catalyst during moderate driving and then partially removed during high speed/load operation.

The sulfur in your gas is going to come out the tailpipe. It can't magically disappear.

 

[Nick1994]

With you guys talking about an exhaust leak, I got to thinking...

The car was rear ended when it was 1 year old, and the left muffler had to be replaced since it was smooshed under the car. I wonder if something is loose somewhere else along the line. It's quiet though.