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R231, 2013 SL63, noticeable bucking upon brake release
I am stumped! From a dead stop, I take my foot off the brake, car begins to roll and bucks a bit. It goes away as soon as you give it a bit of gas. It's considerably more noticeable when engine is cold and warming up. It almost completely goes away after the Engine and oil temp reach operating temperature.
At first I suspected an engine misfire but it does not generate an error code. Any suggestions?.
I am stumped! From a dead stop, I take my foot off the brake, car begins to roll and bucks a bit. It goes away as soon as you give it a bit of gas. It's considerably more noticeable when engine is cold and warming up. It almost completely goes away after the Engine and oil temp reach operating temperature.
At first I suspected an engine misfire but it does not generate an error code. Any suggestions?.
Hard to tell from description but, sounds like a possible transmission issue….
SL63 uses the MCT which has a few shifting complaints when cold.
(edit: are you saying its an idle issue? Because what you wrote sounds sounds to me like 1) the car begins to roll 2) then, bucks on acceleration )
Last edited by crconsulting; Jan 12, 2023 at 02:19 PM.
Can you post a video for us to see how prominent this bucking is??
Originally Posted by clearlink
I am stumped! From a dead stop, I take my foot off the brake, car begins to roll and bucks a bit. It goes away as soon as you give it a bit of gas. It's considerably more noticeable when engine is cold and warming up. It almost completely goes away after the Engine and oil temp reach operating temperature.
At first I suspected an engine misfire but it does not generate an error code. Any suggestions?.
Hi, thank you for the reply. Car in in Drive with my foot on the brake, as soon as i release the brake, without accelerating, the bucking (for lack of a better word) ensues. As soon as I give it gas, it goes away. It does the same when coming to a stop.
Always tough to diagnose drivability complaints over the internet but, It seems like your describing an off idle engine miss…..
So no “bucking” in PARK though?
How long ago were the plugs replaced? Sometimes the coil packs can get damaged on removal if not careful. It might show up in the cold and with heat comes less resistance, thus the engine smoothes out. That should show up if scanned with XENTRY. I’m going to have to assume you’re scanning this with a generic scanner which may not pick everything up.
it’s not the coil itself that gets damaged, it’s the ignition wire coming from the coil. They can be stubborn to remove and can be brittle, breaking internally sometimes. (I would also check the wiring and connectors going to the coils)
That may not be the problem but best to scan it in XENTRY and see what comes up….
Last edited by crconsulting; Jan 13, 2023 at 11:34 AM.
Thank you for the reply. I have to correct myself, the spark plugs have not been changed, my bad. My mechanic said it's probably not the plugs, but since they should be changed at 60K miles, I am taking the car in to change both the plugs and coils and see if that helps. To answer one of your observations, the car is fine with the gear in drive and idling while in drive, but as soon as you let go the brake, no foot on the gas, it starts to buck a bit.
Thank you for the reply. I have to correct myself, the spark plugs have not been changed, my bad. My mechanic said it's probably not the plugs, but since they should be changed at 60K miles, I am taking the car in to change both the plugs and coils and see if that helps. To answer one of your observations, the car is fine with the gear in drive and idling while in drive, but as soon as you let go the brake, no foot on the gas, it starts to buck a bit.
Sounds like either lean condition ( since it manifests when cold) or electrical. I doubt it’s the plugs also. But these cars are drive by wire, so even the gas pedal is wired and can be faulty.
Have it scanned in XENTRY.
If it’s an independent shop, Make sure they have XENTRY to scan the car!
Are you driving in Sport (AMG) or Comfort mode? I.e. D or S (or S+) on the transmission? Asking bc my SL63 “bucks” when cold and in S (and in general off idle in S). I usually put it in D until it warms up and if I’m in stop-and-go traffic.
Are you driving in Sport (AMG) or Comfort mode? I.e. D or S (or S+) on the transmission? Asking bc my SL63 “bucks” when cold and in S (and in general off idle in S). I usually put it in D until it warms up and if I’m in stop-and-go traffic.
Sorry, I just saw your post. Mine does it in "C" mode and in "S" mode. One MB specialist diagnosed the car and thinks it's a head issue. He wanted to do a compression test but since I believe he was off the rails I just took the car back. Bring it into MB next week but I have no confidence that they will find the issue.
Sorry, I just saw your post. Mine does it in "C" mode and in "S" mode. One MB specialist diagnosed the car and thinks it's a head issue. He wanted to do a compression test but since I believe he was off the rails I just took the car back. Bring it into MB next week but I have no confidence that they will find the issue.
Yes sorry I meant "C" not "D" but regardless, if it's happening in "C" also then it's not normal. Best of luck in tracking down the cause!
Local Dealership charged me $1,750 for updating the ECU, TCU. They claimed that that would solve the problem..well, it didn't. They actually delivered the car back with the same conditions, surging when very cold outside temp and slight bucking when i take the foot off the brake. I took the car back and made another appointment, which was last Thursday. I picked up the car today, doing exactly the same thing, but this time they had half of a diagnosis. They wanted to do a tranny service ($2250) to see how the fluid looks. I reminded them that the service was done 3k miles ago. In the end, they shotgunned the issue and told me to replace the tranny. The truth is, they do not employ anyone in their shop that knows how to troubleshoot an intricate issue like this. In the end, I love the car and this is just something that bothered me, but I can stop focusing on it. Thank you all who shared a thought..
Its probably just the nature of the MCT. I have only owned my 2014 S63 a month but I have already gotten used to the strange way it moves from a dead stop. It's not the traditional fluid coupled auto transmission take off that's for sure.
Its probably just the nature of the MCT. I have only owned my 2014 S63 a month but I have already gotten used to the strange way it moves from a dead stop. It's not the traditional fluid coupled auto transmission take off that's for sure.
It must be something we need to "get used to"...lol
I have had a few cars now with the dual clutch systems, and they are all a little different in "feel"....the PDK in my 911 bucked and clunked a bit which was normal, and the TT I had with an early dual clutch system had similar traits. You get used to it.
I have had a few cars now with the dual clutch systems, and they are all a little different in "feel"....the PDK in my 911 bucked and clunked a bit which was normal, and the TT I had with an early dual clutch system had similar traits. You get used to it.
Local Dealership charged me $1,750 for updating the ECU, TCU. They claimed that that would solve the problem..well, it didn't. They actually delivered the car back with the same conditions, surging when very cold outside temp and slight bucking when i take the foot off the brake. I took the car back and made another appointment, which was last Thursday. I picked up the car today, doing exactly the same thing, but this time they had half of a diagnosis. They wanted to do a tranny service ($2250) to see how the fluid looks. I reminded them that the service was done 3k miles ago. In the end, they shotgunned the issue and told me to replace the tranny. The truth is, they do not employ anyone in their shop that knows how to troubleshoot an intricate issue like this. In the end, I love the car and this is just something that bothered me, but I can stop focusing on it. Thank you all who shared a thought..
Wow, how many hours of labour $1,750 just to update software, did you try to get a second opinion from an indie or a different dealership? Not all dealerships are created equal but I guess like you and others said, it is normal. They should had performed SCN Coding or stand still adaption the very least.
Believe when I tell that I have tried other MB "specialists" to no avail. One of them even tried to tell me that I might be dealing with low compression on Cyl # 4. I told him to check for brain activity...lol. Intricate, airline issues like these require a mechanic that can think outside the box, have the necessary Software and Hardware to dive into this and produce an intelligent prognosis. Unfortunately they think that it's not cost effective for them when they can replace a starter and make more money. I am also the problem because I nit pick at things that most people would not even complain about.
Wow, how many hours of labour $1,750 just to update software, did you try to get a second opinion from an indie or a different dealership? Not all dealerships are created equal but I guess like you and others said, it is normal. They should had performed SCN Coding or stand still adaption the very least.
Believe when I tell that I have tried other MB "specialists" to no avail. One of them even tried to tell me that I might be dealing with low compression on Cyl # 4. I told him to check for brain activity...lol. Intricate, airline issues like these require a mechanic that can think outside the box, have the necessary Software and Hardware to dive into this and produce an intelligent prognosis. Unfortunately they think that it's not cost effective for them when they can replace a starter and make more money. I am also the problem because I nit pick at things that most people would not even complain about.
Believe when I tell that I have tried other MB "specialists" to no avail. One of them even tried to tell me that I might be dealing with low compression on Cyl # 4. I told him to check for brain activity...lol. Intricate, airline issues like these require a mechanic that can think outside the box, have the necessary Software and Hardware to dive into this and produce an intelligent prognosis. Unfortunately they think that it's not cost effective for them when they can replace a starter and make more money. I am also the problem because I nit pick at things that most people would not even complain about.
I see. I mean there is nothing wrong of nit picking for something that touts itself as the best or nothing, so obviously you only expect perfection in these vehicles, so continue being you.
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