c63s rough idle
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Newbie
Joined: Jul 2020
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17' c63s
c63s rough idle
Wondering if others have had this issue and if they have resolved it. My idle jumps anywhere from 100-200 rpms to all the way to 1k rpms. Sounds like its cammed. Idle in general is also a little rough at times. It was present stock but even more noticeable with downpipes and tune. Does not affect any sort of drivability whatsoever. However, the rev jump is not always present and every time I try to record it of course it stops happening. Any ideas?
Super Member
Joined: Dec 2019
Posts: 551
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From: Miami, Florida
W205 C63 AMG Coupe
How many miles on the plugs? I had a similar issue and it ended up being a failed spark plug (the ceramic eventually broke and dropped down, covering the electrode and causing a CEL that finally allowed me to have the issue diagnosed). I installed a new set of plugs the next day and the problem was gone. I would start by replacing the plugs, or at least pulling and checking them if they are already new.
Thread Starter
Newbie
Joined: Jul 2020
Posts: 13
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17' c63s
The plugs are new with less than 1000 miles on them. I bought the pre gapped OEM bosch ones from fcp euro. Also replaced coil pack for cylinders 7-8. However the idle jump has always been there even with the original plugs. The downpipes just made it easier to notice.
Super Member
Joined: Apr 2006
Posts: 703
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From: Leesburg, VA
2017 C63S
while I didn't notice this issue with my car, I am pretty sure there is a recall notice where MB did a software upgrade to remedy this issue that others have mentioned happening. Last time I went in they told me and did this to mine
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Joined: Jan 2020
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From: Sydney
C63 S Coupe
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Member
Joined: Jan 2022
Posts: 159
Likes: 42
From: San Diego,CA
2021 AMG C63S, 2008 C300
Sounds like you have might have a vacuum leak. The M177 engine is a MAP engine because of the bi-turbo setup. Most cars are MAF engines. The engine computer is comparing the MAP sensors on both water-to-air Intercoolers in relation to the barometric pressure sensor. So if there is a vacuum leak the map sensor will report more air and the engine computer will deliver more fuel to compensate the “false” pressure being ingested into the induction system and this can cause your idle fluctuation complaint. You can have the induction system smoke tested AND pressure tested. Since the vehicle is able to produce up to 20psi of boost pressure, The induction system needs to be tested at those pressures to reveal any leaks accurately and efficiently.
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Junior Member
Joined: Jun 2023
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c63 S amg
C63s idle
Sounds like you have might have a vacuum leak. The M177 engine is a MAP engine because of the bi-turbo setup. Most cars are MAF engines. The engine computer is comparing the MAP sensors on both water-to-air Intercoolers in relation to the barometric pressure sensor. So if there is a vacuum leak the map sensor will report more air and the engine computer will deliver more fuel to compensate the “false” pressure being ingested into the induction system and this can cause your idle fluctuation complaint. You can have the induction system smoke tested AND pressure tested. Since the vehicle is able to produce up to 20psi of boost pressure, The induction system needs to be tested at those pressures to reveal any leaks accurately and efficiently.
Member
Joined: Jan 2022
Posts: 159
Likes: 42
From: San Diego,CA
2021 AMG C63S, 2008 C300
Junior Member
Joined: Jun 2023
Posts: 35
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c63 S amg
[QUOTE=Shlick96;8882148]You can check with a smoke machine/pressure test. If you don’t see smoke make a soapy water solution and spray the induction system and look for bubbles.[/QUOTE/]
Ok thank you. who do u think it would be best to take the car to? Dealer? I don’t really trust people to touch my car but at the same time I don’t want to take it to the dealer 😂
Ok thank you. who do u think it would be best to take the car to? Dealer? I don’t really trust people to touch my car but at the same time I don’t want to take it to the dealer 😂
Member
Joined: Jan 2022
Posts: 159
Likes: 42
From: San Diego,CA
2021 AMG C63S, 2008 C300
[QUOTE=stock_c63s;8882159]
Anytime. I would take it to an independent reputable German auto specialist shop. Specifically ones that only work on BENZ and BMW. You should have the best luck at one of those specialty shops.
You can check with a smoke machine/pressure test. If you don’t see smoke make a soapy water solution and spray the induction system and look for bubbles.[/QUOTE/]
Ok thank you. who do u think it would be best to take the car to? Dealer? I don’t really trust people to touch my car but at the same time I don’t want to take it to the dealer 😂
Ok thank you. who do u think it would be best to take the car to? Dealer? I don’t really trust people to touch my car but at the same time I don’t want to take it to the dealer 😂
