shaker

I was on my way in to the AMG Performance tour event in Dallas a week ago Saturday and noticed hesitation and jerkiness through acceleration when merging onto the highway.The jerkiness felt like hard transmission changes.
The last time I had this was when I had the CEL issue way back in early August.
Since I was at the dealer for the AMG tour event I left it with service to have it checked out. Service Tech found that there were 2 alarms showing (would not tell me which ones) and that I should bring the car back for further evaluation.
I brought the car back in last Wednesday and was told that what they found was that the accelerator when depressed was not in synch with the throttle, so I asked what the heck does that mean? The explanation I got was that when the accelerator is depressed by 90% my throttle was only opening to 60%. They thought that this might be causing the hesitation. They said they re-synched it but needed to make sure that all was OK with MBUSA and were going through service bulletins etc to make sure. Since MBUSA HQ was closed Friday they asked if I could leave the car with them through Monday.
So am looking forward to having the problem resolved by tomorrow some time.
Has anyone heard of this issue ever happening?
And is there something else I should be worried about?

Blk04cobra1

I have not heard this with the C63, but can relate to my mustang. There was an issue with the throttle body/cable and the accelerator pedal. Plus, since everything is run off computers nowadays, I would say it's possible.

shaker

The C63 is "drive by wire" so no mechanical connections between accelerator and Throttle... all electronics, no cable connections between the two.

MHP

To eliminate the delay in tip in you need a quality ECU/TCU tune. The drive-by-wire delay is a part of the stock calibrations.

shaker

Andy, I understand that there is a delay, but what about the fact that when the accelerator is depressed 90% the throttle is only open to 60%, this is more than a delay issue, no?

Centurionsv230

More than likely a faulty pentieometer in accelerator pedal, Have changed a few on other models.

A reset is just a quick fix,

hcy

drive in comfort mode when you are in city. Just change it to S mode when u want to drive fast. Since the transmission learns n adapt ur driving, if you drive in S in city it will have the problem u are having now, but rmb if u r changing the mode change it when u are at P

peet

For the past week I have had a similar issue. In my case it is from a complete standstill or when switching from reverse into drive. All in S mode - you step on the pedal and for about .5 sec nothing happens, then it just goes. It's kind of like driving a manual tranny and not knowing how very well - kind of embarrassing.

Andy - this just showed up on my car within the last few days. It almost feels like the clutch slips then catches instantly. Though being a torque converter - that's not the case now is it?

Ideas on how to deal with this prior to me showing up on your front doorstep in spring?

Has anyone actually proven that the throttle reset gibberish works? The reason I question the sanity of that is that the clicking and whirring we're supposed to listen to after two minutes - that's just the dampers closing on the car to keep varmits out. Theoretically that has nothing to do with the process of resetting anything drive-train related.

HELP!

MHP

Peet, what trans mode (M/S/C), what ESP mode, and are you throwing a MIL?

We eliminate over 80% of the adaptive learning (as much as we can without mucking other parts of the tune up) of the ECU/TCU with our tuning, so even after babying the car for hundreds of miles the very next time you go to WOT it shifts at redline (1-2) and feels just as crisp as the last time you beat on it.

Thanks
Andy

peet

Thanks for the quick reply...

Trans S, ESP normal, no loss of traction - dry road. No errors showing on any screens.

MHP

ESP normal= On/Sport/Off?

If On/Sport try turning it off and see what happens. You may be triggering the ESP with minute wheelspin not felt before due to the colder weather (harder tires, less grippy road, more power due to denser air). I've had this happen before, feeling a momentary bog off the line, and even though the ESP light didn't flash I know that's what it was as turning the ESP completely off cured it.

peet

Interesting theory. I'll give it a (ahem) spin tomorrow.

However, I am concerned there is more to it than that. All in all the tranny actions of the last couple of weeks have been crap. It went from feeling like "the first slushbox I can live with" to "hey, I didn't sign on for this!"

Today, I was turning a corner. Had the car with ESP on, S with limit to 4th. Decided I wanted a faster exit strategy and clicked to drop it to 3rd. It didn't do it, instead by the time I slowed down around the turn the car put the tranny automatically in second and my 2 second delay instruction (or so it seemed) caused me to make it go into 1st.

In other words, the delay of the computer - from my action, was so long that the car already dropped to 2nd before my request to 4 to 3 was ack'd.

Could be timing, but this is the kind of stuff I've been seeing.

Riddle me this - you would know best at this point, what is the true and only way (short of wiring up the ECU to a comp) to reset the learning? I want to give that a shot too.

later.

MHP

My next guess would be that you haven't been flogging it much causing the ECU/TCU adaptives to bite you in the ***. Go ahead and yank a terminal off your battery for 10 min then reconnect. The other alternative is to beat the **** out of it for around 30 miles in manual mode then retest in sport.
Sorry, I'm not sure how to clear the adaptives in a C63.
The good news for you is won't have to worry about adaptives much longer.

peet

LOL. Thanks Andy.

I did try and flog it around last night - it bought me a field sobriety test and a 20 over the limit ticket. Cop assumed that since it was 12:30AM I was a drunk. Sheesh.

MHP

LOL, damn, sorry Peet! I'd assume cops in Chi-town had bigger issues to worry about than some guy trying to figure out if the adaptive learning in his ECU/TCU were holding him back... Did you tell them what you were doing?



















Seriously though, did it work?

wuyichao

i had the same issue someday last week

when i drove on highway, i switched to S mode then merged into HOV lane. I stepped on the accelerator, instead of speeding up, i felt like the car stalled, and it gave me a transmission break!!! after like 2sec, it speed up.
i thought the car behind me was gonna rear end me!
that was a ****ty experience

MHP

The stock TCU file is definitely not performance oriented, per the application anyway.