2016 C63 AMG Juddering under acceleration - Strangled

[TheMonk1]

HI All,
I'm new on this forum and am using it as a last attempt to save my 2016 C63AMG W205 coupe. Any help or advice will be greatly appreciated. 20,000 miles and owned since new. Fully serviced by MB under service plans.
I have throughly researched the net on my problem and no existing issue is sounding exactly the same.
My car judders under acceleration once it's warm and has been running for 15 minutes.
It's been into Mercedes twice and they cannot find a fault code so to them it isn't a problem. They have applied an update to the ECU but it still has the problem. Feels like it is being strangled, it judders and hesitates under acceleration. If I am very violent with the accelerator and get it to kick down multiple gears, i can get it to clear. It is fine on 100% throttle but anything below seems to cause hesitation/juddering and an uncomfortable ride when warmed up.
I have started to tick cheap things off the list;
Into Mercedes twice for diagnosis - couldn't find anything wrong or get the problem to re-occur. Software update applied.
New spark plugs (seemed better for a day then back to normal)
Re-set gearbox (needed doing but didn't fix the issue)
Into Independent garage that also couldn't recreate the fault but found an exhaust flap sensor 2 had come up. Cleared and it hasn't come up again. But still didn't fix the issue.
It feels to me like a dirty MAF sensor (from experience with other cars)- but the C63AMG w205 doesn't seem to have these. Are there any other sensors that could be dirty that would cause this issue and not throw up a code?

Once the car is parked up if i take it out when still warm it will do it straight away. If i leave the car for over an hour, it is fine again for another 15 minutes until warm and the problem starts again.

Any help will be greatly appreciated as i'm mentally getting prepared to get rid of the car - but I really don't want to as it drove so nice for the first 20K and still looks great.

 

[Bobby Dazzler]

Have you taken it to a transmission specialist? That’s where I would be looking.

You mentioned a gearbox reset. Is this the hold-your-foot-on-the-accelerator-for-10-seconds reset? If so, unfortunately that doesn’t reset anything.

 

[TheMonk1]

Thanks for responding.
Yes it was that method of reset and you’re right it didn’t fix the problem. It did seem to make the changes smoother and less noticeable in comfort and Sport, however, that may have been a placebo effect.
of the time the car runs fine even when hot. It always shifts up and down within expectation. When I get the hesitation and stuttering I seem to get it all the way through the gears, even in manual. It auto shifts up and down but feeling like it doesn’t have the right mix of air and fuel. If I’m in max attack on a fast road it seems to clear but I'm terrifying the public on the local streets.
Would a gearbox malfunction not log a code?
Cheers!

 

[Bobby Dazzler]

O

Thanks for responding.
Yes it was that method of reset and you’re right it didn’t fix the problem. It did seem to make the changes smoother and less noticeable in comfort and Sport, however, that may have been a placebo effect.
of the time the car runs fine even when hot. It always shifts up and down within expectation. When I get the hesitation and stuttering I seem to get it all the way through the gears, even in manual. It auto shifts up and down but feeling like it doesn’t have the right mix of air and fuel. If I’m in max attack on a fast road it seems to clear but I'm terrifying the public on the local streets.
Would a gearbox malfunction not log a code?
Cheers!

O2 sensors would be next on my list then. Most engines are open loop at wide open throttle, which I believe usually means they disregard the O2 sensors.

If that’s the case with your car, then your O2 sensors could be suspect.

 

[Jobsworth]

I’ve replaced a few coil packs on m177 engines for misfires when warm, but you’ll usually get a fault code for misfires. Could your juddering be ignition misfires?

 

[Jobsworth]

https://mbworld.org/forums/attachments/c63-c63s-amg/415827d1519995849-ignition-coil-recall-177-ign-coil-replacement-bulletin.pdf

 

[TheMonk1]

O

O2 sensors would be next on my list then. Most engines are open loop at wide open throttle, which I believe usually means they disregard the O2 sensors.

If that’s the case with your car, then your O2 sensors could be suspect.

I thought exactly the same but I’ve never had an engine check light come on, mileage is pretty good, it doesn’t feel like it’s misfiring and idle is okay but that’s always been a bit up and down when coming to a stop - but never stalled and it smooths within a second.
The o2 sensors are definitely on the list of things to start replacing. Can these be tested or do I just start replacing? I’m sure it’s some sort of sensor but these cars have so many, without a fault code pointing in some sort of direction it can get expensive quick.
The next course of action on my list was to try and get a MB tech to drive it whilst another looks for codes self clearing. During the last year this has proved difficult to arrange with MB.

 

[TheMonk1]

https://mbworld.org/forums/attachments/c63-c63s-amg/415827d1519995849-ignition-coil-recall-177-ign-coil-replacement-bulletin.pdf

Thanks for responding, I’ve checked on MB database and my car is end of 2016 so didn’t get the recall. Also MB said they had replaced some on early models and as you say they always generate a code on the cylinders that are failing. I checked the plugs when the mechanic replaced them recently and they looked fine.
Is it possible to get ignition misfires without generating a code?

 

[Jobsworth]

Thanks for responding, I’ve checked on MB database and my car is end of 2016 so didn’t get the recall. Also MB said they had replaced some on early models and as you say they always generate a code on the cylinders that are failing. I checked the plugs when the mechanic replaced them recently and they looked fine.
Is it possible to get ignition misfires without generating a code?

I would have thought it unlikely, but you never know. I have some spare good coilpacks you are welcome to borrow if you fancy a trip to leafy sussex

 

[TheMonk1]

Thank you very much that is very kind of you to offer. I think I’ll bite the bullet and buy the 4 as it seems likely to be one of those. If not I suppose it’s preventative maintenance for the future!

 

[BlackC55]

Is the judder a miss-fire?

We have come across this before and a set of plugs and a software update sorted it.

 

[TheMonk1]

Hi there, thanks for responding. I’ve had the plugs and the software update both done within the last month. Both made it better for a day, but I haven’t done the coils yet. After a call to Mercedes parts I have been informed that they sell ‘lots’ of coil packs for this model. The concern on my side is I’m not getting any codes but appreciate it could be a progressive problem that will eventually generate a code.

 

[Jobsworth]

In my experience, on the early cars a misfire can occur occasionally on cold start, reset by a key off/key on cycle. Fault codes stored are for misfire on cylinders 1 and 6. The clue is here. 1 and 6 are at TDC at the same time. The error that occurs is because the engine ECU struggles to synchronise the crank sensor with the cam sensor and identify which of the two cylinders is on its firing stroke. There is a software update that addresses this problem. All it does is give a small throttle kick on initial firing. The slight uptick in throttle, and subsequent engine rpm rise, helps the ecu connect the crank sensor dip (missing tooth) and the cam sensor signal (rising or falling signal, depending whether 1 or 6 is on firing stroke) which it was unable to correlate everytime at the slower speed. The fault affects early cars (2015 are the only ones I’ve seen), and can be worked around by the owner with a little bit of throttle while cranking on a cold start.
I didn’t think this issue was applicable to the OP’s situation, as he said the fault he has was only when warmed up.

 

[TheMonk1]

In my experience, on the early cars a misfire can occur occasionally on cold start, reset by a key off/key on cycle. Fault codes stored are for misfire on cylinders 1 and 6. The clue is here. 1 and 6 are at TDC at the same time. The error that occurs is because the engine ECU struggles to synchronise the crank sensor with the cam sensor and identify which of the two cylinders is on its firing stroke. There is a software update that addresses this problem. All it does is give a small throttle kick on initial firing. The slight uptick in throttle, and subsequent engine rpm rise, helps the ecu connect the crank sensor dip (missing tooth) and the cam sensor signal (rising or falling signal, depending whether 1 or 6 is on firing stroke) which it was unable to correlate everytime at the slower speed. The fault affects early cars (2015 are the only ones I’ve seen), and can be worked around by the owner with a little bit of throttle while cranking on a cold start.
I didn’t think this issue was applicable to the OP’s situation, as he said the fault he has was only when warmed up.

Thanks for the detail in the reply, that does make sense. Mercedes have applied a software update to it recently - they were not specific about which issues it addressed, just that it needed to be done. Would the specific update that you mention have been included or do I need to ask them for another known update?
Since we last spoke I have done a few longer motorway journeys. The car is getting rapidly worse and now judders when taking off on cold start, clears after a minute then intermittent judder when lightly accelerating throughout the journey. I never thought I would be saying over taking in a c63 is becoming difficult.
The bhp needle on the screen just bounces when the issue is occurring. Engaging lockdown seems to clear it pretty quick then it happens again 5 mins later. It happens more often when I’m off throttle for 10 seconds or so and then try and use a little throttle.
I can’t believe the car behaves like this and doesn’t generate a CEL light or fault code. I’m going to follow your advice and get the coil packs done over the next week and if that doesn’t work I think she’ll have to go.

 

[TheMonk1]

BTW - Coil packs have improved the driving experience significantly over the past 4 days since installation. However, when the car is hot it still does the juddering now and then (rather than 10 times each journey before the coils were changed). When it is juddering it seems to hang on to this behaviour for a few minutes before reverting to normal, often on its own without me doing anything. I can only deduce that I had a problem with the coils and still have an issue with something else. I am now keen to understand where these o2 sensors are (as it feels like one or two may be acting up when hot) If anyone has the answers to these questions I will be very grateful;

* What are the likely o2 sensors that go wrong and where are they located? Are we talking air inlet, exhaust or somewhere else?
* If it is a clutch related problem - is there a fix or does the gearbox need to be dropped and parts replaced? I have heard some people indicate that there may be an adaptation to the wet clutch and it's parameters of operation. How would one identify this and who can fix it? Cars had an easy first 20,000 miles since new, so i cant believe i've worn out the clutch!

Got a tiny bit of the magic back, but now I want it all back!

Jobsworth are you and specialist indie? I’m prepared to make the journey if you think you can help!

 

[ewheeler6383]

Did you ever find out what the problem was?

 

[Jobsworth]

BTW - Coil packs have improved the driving experience significantly over the past 4 days since installation. However, when the car is hot it still does the juddering now and then (rather than 10 times each journey before the coils were changed). When it is juddering it seems to hang on to this behaviour for a few minutes before reverting to normal, often on its own without me doing anything. I can only deduce that I had a problem with the coils and still have an issue with something else. I am now keen to understand where these o2 sensors are (as it feels like one or two may be acting up when hot) If anyone has the answers to these questions I will be very grateful;

* What are the likely o2 sensors that go wrong and where are they located? Are we talking air inlet, exhaust or somewhere else?
* If it is a clutch related problem - is there a fix or does the gearbox need to be dropped and parts replaced? I have heard some people indicate that there may be an adaptation to the wet clutch and it's parameters of operation. How would one identify this and who can fix it? Cars had an easy first 20,000 miles since new, so i cant believe i've worn out the clutch!

Got a tiny bit of the magic back, but now I want it all back!

Jobsworth are you and specialist indie? I’m prepared to make the journey if you think you can help!

Right then, if coil packs improved it I’m moving more towards spark being the issue. When were the spark plugs last changed? Are they standard plugs? I would move to one step colder plugs and make sure they are clocked correctly. If you are running a high state of tune it’s very possible that the cylinder pressures are blowing the spark out. You need to try a better spark plug and a slightly smaller plug gap.

 

[Jobsworth]

I recently fixed a BMW m135i that was fitted with a hybrid turbo and tuned to 550bhp. It had a misfire issue. Colder plugs and tighter gaps didn’t fix it, but some drag racing coils and leads did. Don’t ask the price

 

[Jobsworth]

 

[Jobsworth]

I thought I had a picture. Everyone likes a picture