OrientBlue3

Thank you for this!! I feel your pain, mine I don't think it as bad as that but still it's very noticeable and awkward for sure.

Makes me wonder that even though it was a software fix if having the car drive like this for so long caused any hardware damage to the clutch or other parts.

LeonPhelps

My Issue is back on my 2016


I went to Eurocharged and they charged me $100 to remove the flash then went to MB dealer to update ECM/TCM and back to Eurocharged to reinstall for another $100


I beginning to think its a issue with the tune

PeterUbers

Did it go away when you went to stock? Time for renntech tune then

OrientBlue3

Did your feel like a clutch issue? Mine is definitely a clutch/TCU-related problem.

Bare in mind this all happens in an instant...foot comes off the brake, clutch engages, engine revs jump up, foot goes on the gas to accelerate (as idle is coming back down) therefore causing the studder I've been feeling. TCU resets (Hold down gas, turn key 5 sec, wait for 2 min, re-start) helps clean this up to make it less severe but does not resolve the issue.

Eurocharged claims they don't touch the TCU part of the car but can anyone confirm that? Can the TCU be at all effected by an ECU flash or is that separate unit entirely that must be flashed?

johnnyblaze

TCU is a separate module. No one has cracked the TCU, the actual module at least, on these cars.

I believe the only thing the tuners can change as far as the ECU is concerned is the shift points, line pressure, rev limiter and probably a tad bit more parameters but not a whole lot. This is purely from my experience after questioning several tuners after switching from my M156 to M157.

OrientBlue3

Noted, thank you for reminding me about the TCU. I knew that and it just slipped my mind.

I dropped my car off today for the dealer to take a look at my problem. Hopefully they can quickly replicate it and flash it.

Does anyone know if like 2012 CCB E63, they must flash both the ECU and TCU together with updated software? I'd prefer they only flash the TCU if that would solve the problem so I don't have to have my ECU sent to EC to be re-flashed again (no 2nd car).

johnnyblaze

I know when they updated the TCU on the 08 CLK Black Series and 08 C63 (for rev matching down shifts) it required that both items be plugged in. Not sure what was written to the ECU or maybe it was some sort of VIN check on the ECU for pairing.

kponti

Seems the times they have updated any ecu software on my car, both ecu and tcu were changed at the same time here too.
The TCU IMO seems similar to the ones in the old 5 speeds, I wonder if the ability to remove it is really the only stopping point???
Its very easy to acess the TCU on the older cars, kinda hard to do on the newer cars

2012 merc amg

Wow, what a hassle I just read this thread, makes me think twice about getting a tune on my car. I've still got the stock plugs too with 42K miles and I guess those would have to be changed for sure.

kponti

Renntech tunes with new plugs (preferably gapped down to 0.022-0.024) should be misfire free. You are coming up on needing new plugs anyway on stock tune

OrientBlue3

Just an update, of course the dealer was "not able to replicate" the problem I experience multiple times each day when driving the car but agreed to reflash the ECU/TCU and re-adapt the wet clutch to the tune of $350. I pick up the car tomorrow and will advise on the results. I will also drive it for a day or so before I send the ECU back to EC to get re-flashed so it will tell me if in fact this was caused by the tune or the ECU/TCU software and clutch calibration.

PeterUbers

I actually think the readapting of the clutch will help. You shouldn't have to pay for that but the tune screwed you

Gotta pay to play, right?

OrientBlue3

Warranty just expired, but they probably would have gotten me either way.

They tell me the hesitation went away. Picking it up in an hour. Leaving for the 4th but will drive it stock for a few days and report back and then also report back again once I have the EC tune back to see if this has been truly resolved.

silvers2k

Hope the issue went away. Enjoy the 4th weekend!

OrientBlue3

Sadly on the first stop this morning on a cold motor, it did it again. So basically, I paid $350 for a car wash.

2012 merc amg

Sounds like you better go back to the stock tuning and see what happens then. Editing to say just noticed maybe you were a stock tune. Maybe something wrong with your trans clutch or something. Have you ever done a trans service on the car. I had one done on mine at 40K miles and for some reason it is so much smoother and performs better now, dunno if they reflashed something or what, but it made a huge difference no more jerky feeling when it is cold now, especially in Reverse like before.

kponti

Definitely keep the tune off the car until you resolve this

OrientBlue3

Yep. I think I'm going to take it in next week and since I happen to be off work for the week, come back the next morning and take the tech on a test drive with the car on a cold motor to show them exactly what im experiencing (despite already showing them videos).

Georgee6086

Just a shot in the dark here, but is it possible that the tranny is a touch low on fluid? I think there sealed units but it doesn't hurt to replace the fluid a filter

OrientBlue3

Not sure. No CEL's or messages. I spoke with my former SA who moved to another dealership and said it could possibly be a transmission valve body or conductor plate based on my description. I've personally never seen anyone with an issue on those items in my time on the forums but at this point, I'm just grabbing at straws.

Georgee6086

He is right if it were a 722.6 (5 speed torque converter tranny) as those were common issues. Our trans are a little different. When th fluid in the trans warms up it expands. There is a certain amount of Line pressure in the trans for it to operate normally. If your fluid is low it there may not be enough pressure when it is cold. But when it warms up its fine because it has expanded. They can check in star for this but they would have to check it with a cold transmission.

Just a thought. Sometimes these mechanics don't have a brain in there heads. I had a problem with my trans in my 1994 e500 and everybody insisted I need to replace my transmission control module including the dealership. All it needed was a quart of fluid.

OrientBlue3

Thank you for this. I will pass it along when it goes back in tomorrow. I had left the car for 4 days after being on vacation for the 4th and the first two complete stops after that cold start it bucked so hard it nearly gave my girlfriend and I whiplash. Even worse than before the flash. My SA said I must pay the "diagnostic fee" of $200 this time and take a foreman on a test drive after the car sits for a day so it can be cold started. To be clear, this is not only a cold start issue, obviously the severity is worse and ton frequency is more common when cold but even when warm, on occasion, the revs will blip when I come off brake and before I can get my foot on the gas. It's obviously a transmission, clutch issue because I can feel the clutch engage, motor rev slightly, then revs drop back. Depending on how quickly I get my foot on the gas, if the RPM's are still falling the car stutters/hesitates. By now, I'll notice it and give it a second before I apply the gas so it doesn't happen.

I'll keep everyone in the loop as to what comes from this next visit.

chiromikey

It's not a fix but as a temporary bandaid, have you tried using the brake hold feature? This will eliminate the time between brake and gas pedal application and maybe keep it from bucking...

OrientBlue3

My 2012 does not have this feature unfortunately. Thanks though!

chiromikey

They all have that feature!