Rotten Egg Smell

[250GTCalifornia]

I'm getting this issue where I am smelling rotten eggs after driving the car after high acceleration. It would seep into the cabin if I reverse into a parking spot. I do not smell it after a cold start, but the weird thing is it doesn't happen every time.

I initially thought that it was the clutch, but people are stating a burning clutch smells like burning breaks and not sulfur/rotten eggs.

I've looked over the internet and they seem to be pointing to the catalytic converter. Yet, I have less than 2000 KMs on the car.

During my break-in period I never accelerated past 4k RPM. Only just recently am I going past 4k, Today I went WOT from second gear and went behind the exhaust and couldn't smell it. Yet, a couple days ago on 3rd gear I went up to 5k and I could smell it.

Anyone else with an Si experiencing this issue?

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[zroger73]

This is normal for virtually every car made with a catalytic converter since the 1970s. In layman's terms, the catalytic converter holds sulfur from the gasoline. When it releases it under certain conditions, you smell it. The amount you smell depends on the sulfur content of the gasoline, speed, vehicle aerodynamics, wind speed and direction, engine and catalytic converter design, amount and length of acceleration, etc.

The quality of the refining process affects the sulfur content of the gasoline. Most gasoline comes from local refineries that sell it to various brands who blend in their own additives and sell it under their trade name. In other words, the highest-price Exxon gasoline often comes from the same refinery that makes the cheapest "grocery store" gasoline - it just has different additive packages.

 

[250GTCalifornia]

This is normal for virtually every car made with a catalytic converter since the 1970s. In layman's terms, the catalytic converter holds sulfur from the gasoline under heavy acceleration. When it releases it, you smell it.

You, technically, should not be able to smell the sulfur since it should have been burned away. If you are still smelling the sulfur it would indicate that there is either too much sulfur in the gas or the catalytic converter is clogged due to a sensor malfunction causing too much gas to be delivered, so it sends it down the exhaust unprocessed.

Are you experiencing this, Zroger? Do you smell rotten eggs during high acceleration? I just want to know if this is normal for Honda's with turbo, since this is my first Honda. I have owned other brands before and I have never smelled rotten gas.

The funny thing is my friend has a 10th gen Civic Si and he said does not experience this, but he has 10K KMs on the car and travels mostly on highways, so I believe even if it did happen to him he wouldn't have noticed, because as you stated, "The amount you smell depends on the sulfur content of the gasoline, speed, vehicle aerodynamics, wind speed and direction..."

I'm just wondering.. Is anybody else experiencing this and does it go away?

 

[zroger73]

Are you experiencing this, Zroger? Do you smell rotten eggs during high acceleration?

Yes. My 2017 Ridgeline does it and so has every one of the other two dozen vehicles I've owned over the last few decades with one exception - a 1969 Buick Skylark that wasn't equipped with a catalytic converter.

"Ever since catalytic converters were introduced, the odour of hydrogen sulfide (H2S), described as ‘smelling like rotten eggs’, has been an issue. This is particularly noticeable when a car in front accelerates after idling (at traffic lights or a roundabout, say) or decelerates sharply after cruising. After combustion in the engine, sulfur in the fuel is released to the exhaust gases as SO2. Under fuel-rich (reducing) conditions, this is converted into H2S over Pt, the suggested mechanism involving the formation of the metal sulfide as a reaction intermediate. It has been found, however, that the amounts of H2S generated when engine conditions become fuel-rich, following prolonged running under fuel-lean (or oxidising) conditions, are larger than expected. The catalyst can apparently ‘store’ sulfur under lean conditions and release it under rich conditions." - http://www.open.edu/openlearn/scien...way-catalytic-converter/content-section-1.5.5

 

[TheBatman]

I'm not smellin nothin' out of mine (except for the Scotch-Gard stuff I applied to all of the cloth). I smell it from other vehicles when they're in front of me, but have never smelled anything from the vehicle i'm driving.

 

[HayaiKuruma]

Stop eating burritos and drag racing right after eating. It's like swimming, after you eat you should wait 15 minutes so you don't crap yourself.

 

[polished1]

I smell this pretty often when I reverse park.

 

[rosedraws]

I just noticed this today for the first time, super strong when I parked. I haven't been accelerating all that much lately. Winter gas? My last tank of gas I got average 6mpg less than since I got the car. note: I'm under 2000 miles.

 

[rosedraws]

Also, it's SUPER embarrassing. I pull up in my shiny cool car that everyone notices, and I step out into a cloud of farty rotten egg smell that I'm sure is now the thing everyone is noticing. Definitely not cool.

 

[250GTCalifornia]

I just want to update everyone that this problem went away for me. I have not run into this smell after various modes of driving. Currently at 4576 KMs / 2843 miles. Last occurred for me around 3300 KMs.

I ended up changing my gas from Esso to Petro, so I don't know if it was the gas or maybe the car was still new, but either way it is gone.

 

[PNW_FC3]

I just want to update everyone that this problem went away for me. I have not run into this smell after various modes of driving. Currently at 4576 KMs / 2843 miles. Last occurred for me around 3300 KMs.

I ended up changing my gas from Esso to Petro, so I don't know if it was the gas or maybe the car was still new, but either way it is gone.

A gas issue indeed.

 

[ssmith]

are you sure its not burning clutch smell under hard acceleration?

 

[Blacklude4]

are you sure its not burning clutch smell under hard acceleration

Burning clutch is typically a hot metallic smell. Comparable to smoked electronics like a fried transformer.

 

[integra15]

Never had this issue in my last 3 4 Hondas. But this one can stink bad after even short bursts of hard driving.

 

[250GTCalifornia]

Never had this issue in my last 3 4 Hondas. But this one can stink bad after even short bursts of hard driving.

It goes away. I spoke to two other people who experienced this. One of them sold their Si, so I don't know if it was still present and the other stated it went away for their Si after 1K KMs.. I'm going to be honest, I thought, perhaps, the catalytic converter or O2 sensor was broken, but it ended up going away by itself.

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