C63 amg random "sloppy" start
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
C63 amg random "sloppy" start
-Hey guys looking for some insight and direction here with my 2011 C63 with 110xxx miles on it. I've been getting a random "sloppy" start up, I don't know how else to describe it. Usually starting up after sitting over night is a normal crisp start, but if it sits for 30mins..... a few hours..... 6 hours....., then its a 50/50 that is will start up sloppy and its getting progressively more common. Always drives perfect after start up with no odd idling or misfires, no codes showing up either. I'm looking to see if anyone else has experienced the same.
-Recent maintenance within the last 5k: spark plugs, injectors, rebuilt cam adjusters (relearn program done), air filters and fresh oil change (the other day)
Appreciate any help as I couldn't find anything similar with searching. **Added video sound clips a few replies down** Thank you,
-Recent maintenance within the last 5k: spark plugs, injectors, rebuilt cam adjusters (relearn program done), air filters and fresh oil change (the other day)
Appreciate any help as I couldn't find anything similar with searching. **Added video sound clips a few replies down** Thank you,
Last edited by IMfam0us; Apr 14, 2023 at 08:44 AM. Reason: added video
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
I think I would start by replacing the injectors, spark plugs and air filters then test it for long enough to confirm if the problem is resolved or not.
These parts are part of a routine maintenance refresh so no problems if it is not resolved and money on parts not wasted.
These parts are part of a routine maintenance refresh so no problems if it is not resolved and money on parts not wasted.
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
I think I would start by replacing the injectors, spark plugs and air filters then test it for long enough to confirm if the problem is resolved or not.
These parts are part of a routine maintenance refresh so no problems if it is not resolved and money on parts not wasted.
These parts are part of a routine maintenance refresh so no problems if it is not resolved and money on parts not wasted.
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Checked for vacuum leaks and found nothing. Tried to capture the start up sound on video. These were both taken after sitting for maybe 20mins after being at full operating temp.
Last edited by IMfam0us; Apr 14, 2023 at 09:07 AM. Reason: adding info
Trending Topics
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
I checked yesterday on the battery, it is dated 5/2021. Checked voltage at the posts while the car was off and running. Voltage was where it should be and constant, but I haven't had a second person to check while starting the car. But, last fall the battery did drain to the point of not being able to start one day while waiting in a parking lot with just the radio going. Has never drained to that point again.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Out Of Control!!
Joined: Jun 2004
Posts: 13,799
Likes: 3,228
2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
I checked yesterday on the battery, it is dated 5/2021. Checked voltage at the posts while the car was off and running. Voltage was where it should be and constant, but I haven't had a second person to check while starting the car. But, last fall the battery did drain to the point of not being able to start one day while waiting in a parking lot with just the radio going. Has never drained to that point again.
you could jump-connect it with another running car (battery to battery) and the starting it and see if it sloppy starts in the circumstances you describe - if not - then it may be the battery
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Thank you for the input! I'll see if I can get someone over this weekend to help me load test it and see if the voltage is taking a big drop. I had completely forgotten about when the battery had drained out to a no crank last fall....that could have done it and the battery just never full came back. I'll update soon
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Waiting on the fcp euro package deal to arrive, went to take everything apart and lucky me.....the bolt holding the pcv in snapped off lol More fun while waiting now
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
late update on things. New oem pcv, intake mani gaskets, intake mani cleaned up and resealed, new bolts. Definitely made a difference but still an occasional start up when the engine is warm/hot that isn't the normal m156 crisp start up.
Newbie
Joined: Jul 2025
Posts: 1
Likes: 0
2011 C63 AMG
Any update on this? Mine has been doing the same thing lately, and I agree the term I would use is a “sloppy” start
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
No updates, sorry. Still does it randomly. Dealer and indy shop said they couldn't see anything wrong. Soneone said crank position sensor could be failing. I haven't tried swapping it out yet. Besides that funk....it still has been running as it should. If you figure anyrhing out, reply for me so we know.
Member
Joined: Oct 2023
Posts: 170
Likes: 38
Can you please re-upload the videos? Mine had one "sloppy start" where it cranked for a few seconds and stumbled for a few seconds before it started up. It has only happened once in the last two years i've owned my car, so it hasn't really bothered me much but it is something I noticed.
Newbie
Joined: Nov 2024
Posts: 2
Likes: 0
From: Uk
C63 W204 Coupe
Did you ever solve. My car...
Replaced the secondary air pump as that had an error
Replaced one Cam sensor as that had an error
One day the PCV body went BANG during a a poor sloppy start and I had to bodge it on to get home but replaced that too along side a new crank sensor tucked at the back of the engine
car is driving better and batter the more I drive it and obviously fix it, next is engine mounts..
But the main issue
Cold starts are 100% perfect EPIC
BUT. WARM/HOT starts are embarrassingly bad, sometimes the car conks out, most of the time I cut it off then do a quick re-start
battery is healthy. no leaks far as I know
Replaced the secondary air pump as that had an error
Replaced one Cam sensor as that had an error
One day the PCV body went BANG during a a poor sloppy start and I had to bodge it on to get home but replaced that too along side a new crank sensor tucked at the back of the engine
car is driving better and batter the more I drive it and obviously fix it, next is engine mounts..
But the main issue
Cold starts are 100% perfect EPIC
BUT. WARM/HOT starts are embarrassingly bad, sometimes the car conks out, most of the time I cut it off then do a quick re-start
battery is healthy. no leaks far as I know
Newbie
Joined: Jul 2025
Posts: 2
Likes: 0
2011 Amg 63
-Hey guys looking for some insight and direction here with my 2011 C63 with 110xxx miles on it. I've been getting a random "sloppy" start up, I don't know how else to describe it. Usually starting up after sitting over night is a normal crisp start, but if it sits for 30mins..... a few hours..... 6 hours....., then its a 50/50 that is will start up sloppy and its getting progressively more common. Always drives perfect after start up with no odd idling or misfires, no codes showing up either. I'm looking to see if anyone else has experienced the same.
-Recent maintenance within the last 5k: spark plugs, injectors, rebuilt cam adjusters (relearn program done), air filters and fresh oil change (the other day)
Appreciate any help as I couldn't find anything similar with searching. **Added video sound clips a few replies down** Thank you,
-Recent maintenance within the last 5k: spark plugs, injectors, rebuilt cam adjusters (relearn program done), air filters and fresh oil change (the other day)
Appreciate any help as I couldn't find anything similar with searching. **Added video sound clips a few replies down** Thank you,
SPONSOR
Joined: Apr 2021
Posts: 846
Likes: 558
From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
Charge your battery see if that helps
__________________
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Hey, sorry for the late reply. I swear I replied the same day but dont see it. Its still there randomly, not as bad but still there. A few ppl said the crank position sensor might be going out. Later this year I might do that along with coilpacks as those are still original and I get a slight miss when sitting at a light.
Thread Starter
Junior Member
Joined: Feb 2022
Posts: 24
Likes: 4
2011 C63 p31
Can you please re-upload the videos? Mine had one "sloppy start" where it cranked for a few seconds and stumbled for a few seconds before it started up. It has only happened once in the last two years i've owned my car, so it hasn't really bothered me much but it is something I noticed.
