Rotten egg smell after 2nd CAT delete
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Joined: May 2018
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C63
Rotten egg smell after 2nd CAT delete
Hi All,
I deleted my secondary CAT today and replaced with straight pipe at my local exhaust shop. I noticed rotten egg smell inside cabin after hard acceleration and race start. Under normal driving is fine. Is it normal to get rotten egg smell after hard acceleration without 2nd CAT?
I deleted my secondary CAT today and replaced with straight pipe at my local exhaust shop. I noticed rotten egg smell inside cabin after hard acceleration and race start. Under normal driving is fine. Is it normal to get rotten egg smell after hard acceleration without 2nd CAT?
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12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
I never had any smells at all with secondary cat delete - it would be normal if you had no cats - do you still have the primary cats? Do you have a tune?
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C63
No tune. Still have primary cats. Only under hard acceleration or race start. I will bring it back to the shop to check.
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Joined: Jul 2009
Posts: 373
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From: DFW Texas
C63 AMG Black Series
What year and how many miles on the car? It's normal for that egg smell to occur after hard acceleration or pulls. It's only a problem if it smells constantly like that. Which would mean the primary cats are failing.
The sole purpose of the secondary cats is to filter what the primaries left behind. I'm sure it removed a majority of the smell before.
The sole purpose of the secondary cats is to filter what the primaries left behind. I'm sure it removed a majority of the smell before.
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2013 c63 amg dev pack
Put the car on a rack or stands and run your hands just above and all around the welds with the car running. You'll feel the leak if there is one. I do this type of work daily and it's very hard to get a clean weld at the top of the pipes (assuming they didn't take the pipes off to do the work) due to space restrictions so if there is a leak it's probably at the top of one of the welds.
Put the car on a rack or stands and run your hands just above and all around the welds with the car running. You'll feel the leak if there is one. I do this type of work daily and it's very hard to get a clean weld at the top of the pipes (assuming they didn't take the pipes off to do the work) due to space restrictions so if there is a leak it's probably at the top of one of the welds.
Last edited by Doc Oc; Oct 8, 2018 at 10:06 PM.
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Joined: Jan 2018
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From: Whitehouse Station, NJ
2012 C63 P31 Sedan
Mine does it too under heavy load conditions only. Good to see it's relatively common, although I still find it strange. I've driven many different cars from N/A to forced induction and various flavors of OEM cats, high flow cats and test pipes, and I've never had this sulfur odor before. For the folks that do have this smell, are you running a tune (I have EC V7)? I'm thinking WOT AFRs may be a factor.
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C63
I am really impressed with 2nd cat delete! it brings the beast alive! loving the AMG Music
