Cold Start Rpm/Exhaust Normal
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 29
Likes: 1
C63S Coupe
Cold Start Rpm/Exhaust Normal
Hello guys,
I have tried to google this issue but cannot find anything useful, so I am hoping you guys can help me out a bit here.
I have a C63S (W205), as you know, when you start the engine up in the morning after a long night, the exhaust is usually louder and the rmp is slightly higher than usual (the cold start). However, recently when I do a cold start, the exhaust and the rmp are just normal, like the car has been warmed up already for some reason. If I then turn the engine off and restart it again right after, then it does a "proper" cold start (louder exhaust & higher rmp). I have talked to an advisor at my local dealership, and I was told that this could happen if the weather is warm. That being said, the weather here at night and in the early morning is like below 10 degree F. I know it is not super cold but I would think it is not warm enough to undo the cold start (unless I am wrong)
I wonder if there is anything I should be worried about and whether if this is considered normal. Any input is appreciated. Thank you all so much in advance. Drive safe!
Best,
Lucas
I have tried to google this issue but cannot find anything useful, so I am hoping you guys can help me out a bit here.
I have a C63S (W205), as you know, when you start the engine up in the morning after a long night, the exhaust is usually louder and the rmp is slightly higher than usual (the cold start). However, recently when I do a cold start, the exhaust and the rmp are just normal, like the car has been warmed up already for some reason. If I then turn the engine off and restart it again right after, then it does a "proper" cold start (louder exhaust & higher rmp). I have talked to an advisor at my local dealership, and I was told that this could happen if the weather is warm. That being said, the weather here at night and in the early morning is like below 10 degree F. I know it is not super cold but I would think it is not warm enough to undo the cold start (unless I am wrong)
I wonder if there is anything I should be worried about and whether if this is considered normal. Any input is appreciated. Thank you all so much in advance. Drive safe!
Best,
Lucas
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 29
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C63S Coupe
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Joined: Sep 2016
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From: Australia
⏱️ 700HP Facelift converted C63 S Coupe with Drexler 3.06 plated LSD
Hey man, some say it's got to do with the battery losing charge. Here's another thread about it: No more cold start.
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Joined: Feb 2018
Posts: 26
Likes: 5
From: PDX
2018 C63S, 2020 GLE580
FINALLY!!!
Someone else has this behavior, admits it and finds it odd. I have brought it up with the dealer at every service I’ve had and they continue to tell me they don’t know what I’m talking about and can not replicate. It happens in a very similar pattern as yours, when the vehicle has been left sitting for longer than a couple of days. If I drive it once a day, not a problem. It did not do this for the first year of ownership which is what struck me as odd. Car runs like a champ otherwise.
I first noticed this behavior about a year ago, as the car was consistently left at the airport. Have not been able to connect to a software update...
Interested to see what comes up on this thread.
Someone else has this behavior, admits it and finds it odd. I have brought it up with the dealer at every service I’ve had and they continue to tell me they don’t know what I’m talking about and can not replicate. It happens in a very similar pattern as yours, when the vehicle has been left sitting for longer than a couple of days. If I drive it once a day, not a problem. It did not do this for the first year of ownership which is what struck me as odd. Car runs like a champ otherwise.
I first noticed this behavior about a year ago, as the car was consistently left at the airport. Have not been able to connect to a software update...
Interested to see what comes up on this thread.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 29
Likes: 1
C63S Coupe
Hey man, some say it's got to do with the battery losing charge. Here's another thread about it: No more cold start.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 29
Likes: 1
C63S Coupe
FINALLY!!!
Someone else has this behavior, admits it and finds it odd. I have brought it up with the dealer at every service I’ve had and they continue to tell me they don’t know what I’m talking about and can not replicate. It happens in a very similar pattern as yours, when the vehicle has been left sitting for longer than a couple of days. If I drive it once a day, not a problem. It did not do this for the first year of ownership which is what struck me as odd. Car runs like a champ otherwise.
I first noticed this behavior about a year ago, as the car was consistently left at the airport. Have not been able to connect to a software update...
Interested to see what comes up on this thread.
Someone else has this behavior, admits it and finds it odd. I have brought it up with the dealer at every service I’ve had and they continue to tell me they don’t know what I’m talking about and can not replicate. It happens in a very similar pattern as yours, when the vehicle has been left sitting for longer than a couple of days. If I drive it once a day, not a problem. It did not do this for the first year of ownership which is what struck me as odd. Car runs like a champ otherwise.
I first noticed this behavior about a year ago, as the car was consistently left at the airport. Have not been able to connect to a software update...
Interested to see what comes up on this thread.
Newbie
Joined: May 2018
Posts: 13
Likes: 1
From: Shanghai
2017 W205 C63 S Sedan Edition 1 DME Stage 2
Thought it was an issue due to stage 2 and decat, maybe battery makes more sense... for me it only occurred once or two when the car had been parked for a long time (a week or so), not happening in the daily drive though.
Last edited by jerrytsao; Sep 14, 2020 at 05:18 AM.
Member
Joined: Aug 2011
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C63 amg esate
Mine has done that since it’s first service more than a year ago, the dealer could do nothing, I’ve just recently been contacted by Mercedes with instructions to take it to the dealer to get it resolved, reference number SRPC2024, they say...’‘If the engine is shut off for more than 67 hours, the the catalytic converter may not be heated up by increasing the idle speed during the next engine start. Should this occur, the catalytic converter would warm up more slowly than intended and it’s possible the vehicle emissions requirements may not be complied with’’
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 29
Likes: 1
C63S Coupe
Mine has done that since it’s first service more than a year ago, the dealer could do nothing, I’ve just recently been contacted by Mercedes with instructions to take it to the dealer to get it resolved, reference number SRPC2024, they say...’‘If the engine is shut off for more than 67 hours, the the catalytic converter may not be heated up by increasing the idle speed during the next engine start. Should this occur, the catalytic converter would warm up more slowly than intended and it’s possible the vehicle emissions requirements may not be complied with’’
Senior Member
Joined: Oct 2019
Posts: 381
Likes: 136
From: AZ
2018 C63S Coupe
Mine has done that since it’s first service more than a year ago, the dealer could do nothing, I’ve just recently been contacted by Mercedes with instructions to take it to the dealer to get it resolved, reference number SRPC2024, they say...’‘If the engine is shut off for more than 67 hours, the the catalytic converter may not be heated up by increasing the idle speed during the next engine start. Should this occur, the catalytic converter would warm up more slowly than intended and it’s possible the vehicle emissions requirements may not be complied with’’
To the OP...I never had this problem until my car was tuned (with catless downpipes) and it was no longer my daily. I would drive it every two weeks "at least" to keep things moving and I would notice back then it would do that to me if it sat for more than 3-4 days. I would then simply shut it off and restart and it would do a "cold start". I thought maybe it had to do with my tune???
However, recently I went back to driving the car everyday (I missed it) and sold my daily. Since then I do not have that problem. It "cold starts" every first time of the day. And I live in the desert where we have had a record number of days of over 110 degrees outside (my car is garage kept). So the only thing I can think is it has something to do with when the car sits for a while...maybe my Boy "Jimmy_c63s" is on to something and it is related to the battery draining when it sits for more than a few days...IDK???
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Joined: Oct 2014
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From: New York
c63s
This is normal after they did an ECU update (forced, even when I said I didn't want it), which has now removed the "loud" idling and it sounds like the car has been warmed already. It doesn't matter if it's warm, hot, freezing weather, as long as it's hasn't been turned on after 2 - 3 days it will do this.
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From: Flat Earth
AMG C63s Sedan , AMG C43 , AMG G63 , GLK 250
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