Funkwagen

EDIT: Important, but for diesel w204s, M276 engines and models in general 2013+ , the lastschlagdaempfung parameter may already be disabled.

This post assumes you have some knowledge of the software used. I'm not entirely comfortable making a full walk-through for beginners, as this is potentially risky.

After spending quite some time tinkering with and learning about DAS/Xentry/Vediamo, I believe I've almost completely solved my issues with throttle lag on my car. Since owning the car I've noticed that depending on how the car is driven, like through heavy traffic or on country roads, the throttle response to the gas pedal does not seem to stay consistent. For example, if I start off driving the car in stop and go traffic, the pedal seems to become "lazy"; next time I mash on the gas, there's a very noticeable delay in throttle input and sometimes the car doesn't shift down when it should, either in C or S mode. It was quite annoying, and on a few occasions, kind of risky. Aside from that there'd be a very noticeable difference in the way the car performed on a day to day basis, sometimes it felt sluggish, and other times it felt pretty quick. I really didn't like how it was unpredictable.

This is discussed in a threads like this, and it appears that ECU adaptations are the cause for this. I'm sure the adaptations would be effective in some cases, but where I live and how I drive, the adaptation process seems to have a difficult time calibrating the throttle response, and the result has been pretty undesirable to me. It seems others have the same issue, and have tried solving it doing the simple TCU reset. This reset does work, very temporarily. Every time I tried it, it'd help for a few drives but then it'd revert to sluggishness. I went over 10,000km after pulling the car battery and doing the TCU reset to see if the car needed a long time to "learn", and it did improve, but the inconsistency/unpredictability of the throttle input, and delay, still remained an issue.

I'm very glad to have spent the money getting a diagnostic multiplexer, as it's allowed me to learn quite a lot about how these cars operate. On top of that, I've done a bunch of tweaking to get things to how I'd like. If you have access to one, or know someone who does, the following tweaks have solved these problems for me. This could likely be accomplished in Xentry rather than Vediamo, but I was unable to get access to the necessary settings through Xentry myself. I Please note, I have no idea the effect this will have on warranty, as my car is completely out of any warranty..

MrScott52, a very helpful member of Benzworld and also possibly MBworld, posted a youtube guide on how to enable a few parameters to increase responsiveness of a diesel variant; these tweaks seem to make a difference with my 2.5L M272 w204 as well. (I'll link the video in a following reply.)

Attached below are the necessary parameter changes for the ME 9.7 ECU in Vediamo, which solved my issues with throttle delay (many listed in MrScott52's video), and here are the descriptions of each:

#1 (Lastschlagdaempfung) This is the most important one. This parameter seems to be the main culprit for the inconsistent feeling throttle response and sluggishness, and I believe it causes the wonky throttle body adaptations which I find so awful. Disabling it has removed most, if not all delay in throttle input. It is referred to as "load-reversal damping" in Vediamo (german), but it is the "Throttle Change Damping" parameter in Xentry. I changed this parameter about a month after the others, and it definitely had the most significant impact on throttle response, and now the throttle is very consistent in performance. I believe this parameter is more directly related to the actual throttle body than the gas pedal, unlike the next parameter.

#2 (Pedalkennlinie) This is the pedal curve parameter. My car had KLD4 as default. You can play with this, and possibly leave it at KLD4. However, I changed it to KLD2. From what I understand, KLD2 is meant for cars with a manual transmission, and as such, I'd expect the pedal curve to be the most "natural" feeling to the driver. In contrast, I believe KLD4 is more responsive, but "jumpier" (more erratic in terms of throttle input). Combining KLD4 with disabling the throttle change damping parameter may be undesirable in terms of comfort/consistency.

#3 (Momentenbegrenzung) This is the torque limit parameter. The main effect I've observed from disabling this is that the car doesn't reduce throttle/torque as much while cornering anymore, and the car seems to accelerate slightly faster from a standstill than before. May not be necessary to fix throttle delay, but I find it favourable.

#4 (Momentenerhoehung Getriebe) *This may already be set to the MSG option* This parameter is supplementary to #3. Like MrScott describes in his video, it allows the engine ECU to monitor torque output and send it to the transmission, but keeps it within safe/comfortable limits. I find this parameter to improve gear shifts very slightly; torque input and acceleration remains very steady throughout gear shifts. I believe it very slightly improves acceleration, even compared to only having the torque limiter disabled. Do not change this to the GSG setting. Doing so resulted in some very uncomfortable shifting. I'm not sure if there'd be a long term effect on the gearbox here, so just don't as a precaution. The option highlighted in black is the default setting - the ECU is not allowed to increase torque to the gearbox depending on measurement.


With all these parameters changed, I have my car performing the way I'd like it to. It's performance remains far more consistent, there's significantly less throttle lag, and it does actually accelerate faster (I've measured), but only very slightly. Starting off in C mode on an incline also no longer feels like as much of a strain. Now, all of this being said, if you have the tools and such to do this yourself, or know someone who can, you do so at your own risk. I've driven over 10,000km already without any negative effects of this, but I just don't want to be responsible if anything goes wrong. I can't imagine anything would, though. If you are willing to do this yourself, please be aware that there are many ecu parameters that are difficult to understand, and modifying them at all could potentially cause irreversible damage. I do not recommend making adjustments to any other unknown parameters without thoroughly researching their function and/or purpose.

p.s the screenshots were taken in simulation mode, I didn't think to screenshot anything while I was actually connected to my car. The highlighted values are still of course relevant.

Funkwagen

Thank you MrScott52!

xEryx

Wow awesome dude. I bought a Star C4 a few weeks ago and I'm still trying to learn, but is pretty complicated. What resources did you use to learn? I bought it with the main purpose of updating my 2012 HU to 2013 theme. I have Vediamo and all that stuff setup, but is cold and I don't have a garage, so I haven't spend much time figuring out the hook up part. I would love to disable that first setting. The lag when I step on it is horrible sometimes to the point that I start moving forward in anticipation on the seat and the car still doesn't go.

I bought this one

Funkwagen

I spent a lot of time reading various things on a forum called *******, lots of resources there. You're past the hardest part if you have Vediamo/Xentry set up properly. As for the actual parameters, I spent a lot of time googling specific things, translating everything from German and comparing them to parameters that were in English in Xentry. I'm currently trying to decipher most of the parameters for the front SAM unit, but it's very difficult since there are a lot of non-descriptive German acronyms. I'm currently looking for a way to disable the sidemarker lights, but can't find any obvious setting for it. I have the majority of the ME 9.7 parameters translated, but some of them don't offer much help as to what their actual function is. If there's any interest I could post those, but I don't think they'll be of much use.

I'm using a reasonably good quality SDConnect clone like this that I bought, the only issue I have with it is that I can't get it to work with DAS, but I think that's more likely to be a software issue than hardware.

By the way, if you do modify the first parameter, you may want to change the pedalkennlinie parameter as well. I'm not sure how well it'll work with the default pedalkennlinie setting, but you could always try.

xEryx

Looks like you bought the OEM replica. I bought the "cost effective" version which should have the same functions, though not as nice looking. ******* is where I've been learning all about the HU software and what I need to look for etc.

I can imagine how complicated it must be to translate those parameters and then have to figure out what they do without much description.

michail71

This seems similar to what the TCU flashers claim to do. I wonder if this is how they do it or if different remappings are done?

Is this something a typical independent specialty shop would be able to perform? Would it also apply to M271?

michail71

On a side note, the GLA I have on loan seems to have a more immediate adaption process. If I'm in E mode and do a "high speed traffic insertion", as I call it, the car will get stuck for a minute or two in uncomfortably low gears.

Mercedes seems to be trying too hard to out think their drivers.

Funkwagen

I'm not sure how TCU flashers do what they do, but it's possible.

As for independent shops, they may or may not. They'd require a Mercedes diagnostic multiplexer (possibly a genuine mercedes multiplexer for legal reasons?) and would have to be willing to make such modifications. I just checked the ECU file for the M271 (Sim271ke2.0, as opposed to the M272 ME9.7) and there is an parameter called "Lastschlag" with the option of disabling it. I have no way of telling whether or not it'd be the same thing as "Lastschlagdaempfung" in the ME9.7 ECU, unfortunately.

This tweak has solved for me the same issue you're having with the GLA; that unpredictable sluggish/wrong gear/lack of throttle.

michail71

The GLA is just a loaner. I'm finding it unpredictable in different ways. The C250 will get sluggish. The GLA often doesn't upshift or has overly abrupt and unexpected downshifts. Comparing the two I would say the GLA is easier to control, especially since it has a manual mode as standard with paddle shifters. It also has a short term adaption that kick in with aggressive driving.

With the C-Class you just never know how the throttle will respond. I mentioned in another thread the throttle either wants to be in granny mode or aircraft carrier launch mode. I just want to control it with precise throttle application.

Merserybenze

Funkwagen - i'm willing to figure this stuff out as i like my w204 and want to get rid of the lag. Tuning flash did improve slightly but wasn't worth the $400. Can you opine on this as to suitability?

http://www.xcar360.com/super-mb-star...dersystem.html

Funkwagen

Wouldn't be able to tell you if that specific one is worthwhile or not, it seems that there's a lot of different manufacturers and quality levels of multiplexer clones. Here's the one I went with, however I didn't bother with the HDD/software they included or a dell D630 laptop. I have a background in computers, so I set myself up a vmware virtual machine and installed all the software with the (occasionally somewhat difficult to follow) information on *******. I have heard of people having problems using VMware, but I didn't experience any myself.

As for the hardware itself, mine is of decent quality. I have no real complaints with it other than it losing it's WiFi configuration once drained of battery (which happens quickly, but it's not really an issue since it draws power from OBD when connected), but I prefer using a cable connection anyway.

P.S I will warn you that if you're not very familiar with computers/configuring software/some basic computer networking (IP address assignments, etc), you might have a hard time getting everything to work. Definitely look into the details of getting everything set up before buying. I wish there were a complete and total guide to setting up everything, but there isn't really. Getting everything working properly took quite a lot of reading and searching, and a couple of days of tinkering. Patience is a plus.. if I had to compare this to something else in terms of difficulty (computer-wise), I'd say it's similar to setting up a microsoft exchange server without errors.

xEryx

I bought this one: http://www.aliexpress.com/item/2014-...8-d1dcad021c6d

It comes with three HDD options, I chose External USB HDD that I copied to my laptop SSD and I can hook up the multiplex using USB adapters provided.

Lol, good luck setting up Exchange without having to do a dozen things first!

Funkwagen

I almost went with one of those because of the cheaper price, but didn't because of the issues people were having using the USB to serial connection in Vmware. That said, it's very similar to the one MrScott52 was using in his video and he's using Vmware just fine.

That's what I meant when I mentioned the exchange server Looks relatively straightforward on paper, but there's always a number of hiccups and a bunch of specific things to do to get everything working smoothly..

ghlkal

I appreciate your efforts in investigating this, and in taking the time to post your results.


You indicated that the Lastschlagdaempfung parameter had the most effect, but that was the last (4th change you made). I'm wondering if you tested by resetting the other three to their default state and flashing just the change to Lastschlagdaempfung. Would merely changing Lastschlagdaempfung give us the result we're all looking for -- reducing throttle lag?

Funkwagen

I'm actually going to test this out this weekend, I think I have a way of taking actual measurements of the changes. Basically, I'm going to try comparing pedal input to throttle valve actuation (via OBD data) between stock, pedal curve change, and the pedal damping mod. If I do, I'll post the data

michail71

I may get around to this in about a year or so. Unless someone in the south Florida area has the equipment and is willing to help. So this will be a valuable resource.

xEryx

Once you verify which settings had an effect, I will be sure to give it a shot.

Merserybenze

i would pay to have this change made...there's a business opportunity here!

michail71

There is a TCU flash available that sounds kind of similar that runs $800. I suspect it may go a little deeper and remap shifting points. The price seems good given the alternatives. But the alternative sounds fun.

Carsy

Thank you Mr.Funkwagen, a very interesting & informative video which gave me a much better idea of the workings & possible adjustments in modern vehicles.

Interesting that it is possible for dealerships to improve many responses . It is a pity they do not take up the challenge. I wonder what possible reasons they have to decline when it is so easy & inexpensive to make a car fit the needs of the owner ? .

C3502012

Hello folks
I have a c350 2012 4matic

From past 2-3 days wheb i cold start my car with the push to start the engine would crank for a split second and stops. I have to wait few seconds and push the button second time to start the car.
Do ineed a new battery ? Or is it the starter ? Or is it something to do with crankshafts or engine?
Thanks

Funkwagen

Well, I've run into a problem testing out the Lastschlagdaempfung parameter.. When it's re-enabled after being disabled, it doesn't take immediate effect, and I guess has to be driven around for some time so it can "adapt" again. I'll have to re-enable it for a couple of days to measure the change. But I'm just about 100% confident there is a large difference.

I left it disabled anyway and compared KLD2 with KLD4.. KLD4 still feels far more responsive than it used to (with LSD enabled), but actually does feel a little more "relaxed" compared to KLD2. Off the line acceleration actually feels slower than with KLD2, and in general, the pedal is less sensitive than KLD2. I'm a fairly spirited driver so I definitely prefer KLD2, but some people may prefer KLD 4 (which is default for a C250 M272 2.5L). Basically, the pedalkennlinie parameter is still relevant to throttle delay/response. There's a noticeable difference between the two settings, and I haven't tried out 1 or 3. (people seemed unhappy with KLD 1 in another thread, KLD3 looks to be reserved for the M-class SUVs.)

Data collection for actual measurement was a mess, I'll need to use a different program to do it properly..I was hoping to have some data I could put in a chart. I'll give it another go soon.

You're welcome! I'm not the creator of the video, though! That credit goes to MrScott52 on benzworld. I think I've read somewhere that they're not actually permitted to make these changes for some red-tape reason. Through the official tools, authorization for SCN coding must be obtained, etc. It seems to be quite an administrative process for something so simple. Since a lot of dealerships are usually less than helpful, I don't imagine they'd be very accommodating for a request like this..


Do you have any more info on this TCU flash? It probably does remap some shifting points, etc. I haven't been able to find a way to easily do that, unfortunately. So far I've only dealt with variant coding tweaks, been a bit hesitant to touch anything to do with firmware flashing until I know exactly how to go about doing it.

xEryx

Makes sense since the system actually learn how you drive and after being disabled, it probably has to relearn which takes a few days.
I will try to do my HU update today and after that look for the parameters in Vediamo to see if they match on the C300.

Carsy

Yes, I am sure you do not have that "down under " accent. Thanks for the posting.

Merserybenze

this looks like it has everything required to achieve what you did?

http://www.ebay.com/itm/DELL-D630-ME...861005&vxp=mtr