[Z06] Rotten egg smell!!!
Thread Starter
Le Mans Master
Joined: Dec 2005
Posts: 8,564
Likes: 950
From: Communist Colorado
Rotten egg smell!!!
Ive done a little research and anyone who has had this issue is running stock cats... I have headers and Random Tech cats. I had just filled p with Shell premium. I drove about 50 miles without issue. I was in heavy traffic for probably 20 minutes and there was no smell. Went the rest of the way, another 50 miles...all good.
On the way home we noticed the smell coming in the A/C vents. Switched to recirculated air...better..but not gone. Then the smell worsened and almost made us sick!!
Thinking back, I really noticed it when decelerating and then stopping. it was horrible...worse than I remember from any car thats had the issue.
Could my cats suddenly just go bad? I have NEVER smelled this from my Z in the 4 years Ive owned it until this point.
Car runs just fine, no other issues.
On the way home we noticed the smell coming in the A/C vents. Switched to recirculated air...better..but not gone. Then the smell worsened and almost made us sick!!
Thinking back, I really noticed it when decelerating and then stopping. it was horrible...worse than I remember from any car thats had the issue.
Could my cats suddenly just go bad? I have NEVER smelled this from my Z in the 4 years Ive owned it until this point.
Car runs just fine, no other issues.
Safety Car
Joined: Apr 2011
Posts: 4,260
Likes: 429
From: Houston TX
Could you have ran over something that got wedged against your exhaust?
When I had a lowered truck I had an already deceased animal get caught underneath and against my y-pipe. It was not a pleasant smell at all...
When I had a lowered truck I had an already deceased animal get caught underneath and against my y-pipe. It was not a pleasant smell at all...
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
i have random tech cats
why is that?
well the oem cats have platinum in them and are built one hell of a lot better.
running rich will destroy an aftermarket cat pretty fast.
while back when i had an autocross honda it used a japaneese type r engine which had a 2.5" header and exhaust. didn't work with the US spec 1.75" exhaust and cat. so i get a magnaflow cat and 2.5" exhaust. the cat lasts about 1 year before it melts.
i then mail order a used cat from a wrecked car in japan that's OEM honda. went 3 years and was still fine when i sold the car
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Tech Contributor
Joined: Jan 2004
Posts: 20,030
Likes: 289
From: Wylie TX --> Less is More, except under the hood !
I have LG Pro headers with Random Tech high flow Cats.
Running them for 8+ years now.
They were $400 for the pair 8 years ago.
I have never had issues with smell like your describing.
I would look under your car to see if you melted something on the headers. I once drove over a plastic cup from a coffee shop. I could smell coffee and burnt plastic for a week on my car.
It made my garage smell like crap too. I had to get under my car to scrape it off my headers.
Toque
Running them for 8+ years now.
They were $400 for the pair 8 years ago.
I have never had issues with smell like your describing.
I would look under your car to see if you melted something on the headers. I once drove over a plastic cup from a coffee shop. I could smell coffee and burnt plastic for a week on my car.
It made my garage smell like crap too. I had to get under my car to scrape it off my headers. Toque
Tech Contributor
Joined: Jan 2004
Posts: 20,030
Likes: 289
From: Wylie TX --> Less is More, except under the hood !
it's the cats
Burning Brakes
Joined: Jan 2004
Posts: 1,231
Likes: 81
From: Paris Tex
Bad smell
I experienced an smell like that. I bought a new Trans Am in 75 and took my girlfriend for a ride that car started doing that. I thought it was my girlfriend. I ask her to please stop.
Safety Car
Joined: Sep 2007
Posts: 4,168
Likes: 21
From: Sunniest city on Earth
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
My car (stock cats) will stink on occasion, but typically only if it enters PE mode. Oddly enough, I've never smelled it on the track. A quick crack of the throttle will bring it about, but the smell goes away quickly. You said yours was on decel though? That's very odd, because the car should be in DFCO (decel fuel cutoff) mode if the RPMs are over 1500 so there should be nothing to stink. DFCO isn't lean, it's NOTHING, so nothing to stink. Could you be more specific on the decel conditions? I'm wondering if something isn't up with your tune, because it should only stink like that when the cats are overwhelmed with fuel.
Thread Starter
Le Mans Master
Joined: Dec 2005
Posts: 8,564
Likes: 950
From: Communist Colorado
My car (stock cats) will stink on occasion, but typically only if it enters PE mode. Oddly enough, I've never smelled it on the track. A quick crack of the throttle will bring it about, but the smell goes away quickly. You said yours was on decel though? That's very odd, because the car should be in DFCO (decel fuel cutoff) mode if the RPMs are over 1500 so there should be nothing to stink. DFCO isn't lean, it's NOTHING, so nothing to stink. Could you be more specific on the decel conditions? I'm wondering if something isn't up with your tune, because it should only stink like that when the cats are overwhelmed with fuel.
I thought cats gradually failed... I never once had the smell before... so Im not convinced its the cats. Random Tech cats are decent cats.
AU N EGL
I have used the same fuel in the car before, from the same station... ALTHOUGH... I have not in a long time. I usually go to Conoco and use their premium.... Does Shell have some new formula or something?
Thanks Guys!!
