2016 E550 I want to try to tinker with, but have concerns

Noob here, first post. I have a 2016 E550 Coupe (C207, M278 4.6L twin turbo) and have questions.
I hear the ECU on this can brick when I try to use an HP Tune, or apparently it's some "PCM modification" you need to do before you use HP Tune. This of course worries me a great deal because I've been looking for a replacement ECU and it's just short of impossible. So rather than replace it, I figured maybe I can adjust mine via the tune and get it working right. But I can't afford to brick it...

My problem is low boost, about 7-8psi when it should be 13, and it's being commanded to do this, it's not a mechanical issue. The MB Dealer says nothing is wrong because Xentry says so. So annoying... I have Xentry too, which is basically useless imo.

I also have an OE Tune which bumps the boost to about 12psi, but I'm guessing it should be more like 17? My options are likely zero in finding the actual problem so I thought I could simply force the boost higher with HP? If it's shorting me 5psi, or x%, then I bump boost in the tune to that much over what I actually want and I'd imagine it would work? Eg; plug in 23psi and net 17.
I also heard tunes like OE don't play well with HP? I don't know what that means, but if so, could I use HP to see what all the OE settings are, then remove the OE tune and duplicate it in HP?

Thanks

@chevota

The PCM modification is no longer needed as it once was. Bricking a controller is a risk whether with HPT or a professional tuner flashing a tune. You just want to take your time and do the steps correctly, make sure your car and laptop/device battery are fresh and fully charged, and a good data cable connection (firmly plugged in, no worn out connectors or USB port like in an old laptop that could drop communication) to minimize that risk.

In what conditions did it show 7-8 psi? Which gear, rpm, etc, and was this a stored value or read live? Does your car feel like it's making good power?

You want to make sure you're getting accurate boost feedback before making changes. I'd be curious to see what HPT VCM Scanner reports for boost.

*If* it's really peaking at 8 PSI in the higher gears, then you may have a boost leak or solenoid issue.

Reverse engineering the tune based on scanner data would be very difficult. BUT learning to tune these cars is rewarding if you're stubborn and patient.

Thank you for the reply Schnell
The boost is being commanded not to exceed 8psi, no leaks or other issues. Depending when I floor it, gear/rpm, boost will often flash past 8, sometimes 50% past, but just for the split sec it takes to open the wastegates.
The gear makes no difference, 1st, 4th, doesn't matter. The only diff is by how much it'll go past 8 because it spools up faster under certain conditions, like holding 2nd gear, then at say 3k I floor it I usually get good boost for a fraction of a sec, it breaks the tires free, then as soon as it does it's over.
The power is pathetic, with the exception of that very brief moment before the wastegates open, so we're talking 250ms?

I can tell it's commanded because I can watch the wastegates open and adjust to maintain that psi, via live video, while I watch Torque Pro, or Xentry, tell me the psi.
To additionally show it's being commanded, I can install the OE tune and that max 8 psi value changes to a max of 12. Power increases of course, but still < stock. Not sure if I trust Torque Pro to tell me HP/Tq but it's about 250 at peak for each, and about 300 with the OE tune.
I have some U codes when I scan the car, but nothing that seemed important and the dealer said they are irrelevant and have nothing to do with the issue. Not that I'd know for sure, but he said he sees all of those all the time and they are not important, just a glitch. Xentry also says they only pop up once here and there, and most all pop up at the exact same moment. The dealer believes it's low voltage on cranking that does it.

What is causing this boost loss I don't really know for sure, but I can only assume it's either a fault in the ECU, or some fault somewhere is telling the ECU to pull boost. I have no way to tell but it makes sense since I get two different values with/without the tune and they are consistent.
This happened suddenly one day btw. I floor it pretty much daily, then one day I was like, wtf... That was June '20, and I bought the car in May '20. So it ran right for a month, and it's been this way all that time and I can't figure out why...

What do you think about the OE tune? What happens when you use HP on an existing tune? Because all I really want is to add the boost back to the OE, nothing else. What psi the OE was set to I can only guess, 17, 19, who knows, but I also don't want to over pressure my intercooler and I'm not sure what it can handle.

Bricking a controller is always a risk in all platforms,
what I usually do if I'm going to use hptuners to tune a Mercedes is first of all get a backup of the pcm using ktag or any other tool.

Get the backup of (Micro + eeprom) or sometimes Micro only will do.

The risk is only on one thing is when you try to read MED17+ using hptuners it would ask you to make a one time update to patch the pcm (sometimes it stops in the middle of the process bricking the pcm).
If the update process gone smooth then you will be able to read it for the first time and you wouldn't need to patch it again anymore to read it again.

Steps I would do:
1- Get backup of the pcm (Micro + EEPROM)
2- Fresh car and laptop battery
3- Good USB cable + Internet connection (important)
4- Have fun and dont be afraid we always live on the edge when tuning !!

Regarding OE tune, they use binary files so you could flash the tune with any tool if its your car specific then read it using hptuners to adjust the tune using VCM editor.

M278 = 8-10 psi (stock) totaly normal
M157 = 11-14 psi (stock)

Backing it up with KTag is apparently $2000 for a "Master" unit but I don't really know because like most websites they are not clear at all about what you need. Do I also need a Slave? Other hidden costs?
Then I could recover a bricked ECU/PCM?
But then Schnell said it didn't need this risky HP Tune update/patch at all, which is confusing.

What would be much better is getting a place to sell me a used virginized ECU and my local MB dealer will clone it for me and that will be my backup and possibly the fix for the entire problem. Or does it even need to be virginized? Whatever the case, surely there is a place that will sell me one? Any ideas?

Not sure where you got the M278 8-10psi is normal. I'm NOT trying to be a d!k, but I simply don't believe that. Or maybe that's for the most detuned motor they put in some cars.
It is good news that I could read the OE tune info with the VCM editor. That alone would be worth the price to me.

Thanks for the re outlaw :)

I was referring to the PCM hardware modification that used to be required, not the software patch.

10-11 psi is the most you'll see in a stock E550. Around 13 psi in the stronger factory tunes (SL, CL, etc).

Hmmm... It seems hard for me to believe it can make the power it did on 8psi. Lets say it did, and my oem boost is normal, how can it be 40% low on power across the board?
My throttle is opening all the way, timing is good, fuel is good. So how can it possibly not make the power? Nothing I'm aware of can cause a power loss that big without obvious side effects.

Thanks again for the reply because I'm literally out of options as to what it can be, but if the psi really is correct then I'm worse off than before. But I don't believe the tuned psi would be lower than the stock 13 of an SL model. Nor can a tune increase torque at the wheels by the claimed 22% without increasing boost, so tuned boost has to be a good bit more than 13.

Quote:

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Originally Posted by chevota

This happened suddenly one day btw. I floor it pretty much daily, then one day I was like, wtf... That was June '20, and I bought the car in May '20. So it ran right for a month, and it's been this way all that time and I can't figure out why...

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If this was a sudden change then clearly something went wrong, either a leak somewhere or something else causing reduced power. Have you tried disconnecting the battery for an hour or so to see if you get full power back?

Bro its not such a big deal just get pcmflash or clone ktag (get a backup),
then read your pcm using hptuners it will ask for an update just follow the process, tune it and get the boost you want!

So a Chinese KTag, like this? www.aliexpress.com/item/32968256925.html
I buy that, nothing else, and I can backup my ecu? Then if the HP Tune fix bricks it, this thing can recover it?

Yes I tried disconnecting the batt, several times, including the one in the trunk. Left it like that for a whole weekend once. It does nothing at all.
Well, not nothing: The last time I did it my mirrors would no longer fold in when locked... Tried turning the feature Off, then back On, still nothing. Can't wait to find out what else fails on this pos.

If there was a leak then the ECU would not open the wastegates. And remember, it is capable of 17psi for a split second before the wastegates open.

Quote:

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Originally Posted by chevota

So a Chinese KTag, like this? www.aliexpress.com/item/32968256925.html
I buy that, nothing else, and I can backup my ecu? Then if the HP Tune fix bricks it, this thing can recover it?

Yes I tried disconnecting the batt, several times, including the one in the trunk. Left it like that for a whole weekend once. It does nothing at all.
Well, not nothing: The last time I did it my mirrors would no longer fold in when locked... Tried turning the feature Off, then back On, still nothing. Can't wait to find out what else fails on this pos.

If there was a leak then the ECU would not open the wastegates. And remember, it is capable of 17psi for a split second before the wastegates open.

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Yes Chinese will do.

sometimes the culprit is this Pressure valve if it turned black or too old, replace it

Attachment 116782

After reading some info about the KTAG it appears to me it hasn't been able to work on my ECU (MED17.7.3) until a few months ago. I can't say for sure because I don't know much about it, but I know for sure it said it could not clone the ecu before a few months ago. If so, I'd assume the chinese KTAG clones are not able to so I didn't buy one yet. That's a bummer because I found a used ECU on ebay and bought it, assuming the order doesn't get rejected like my mboemparts.com order. From what I've gathered my ecu is a pita, which I guess explains the KTAG and HP Tune issues.
The ECU was pulled from a 2015 E63, so with an luck it'll work. With even more luck it'll somehow work better than oem.

If I receive the used ecu I then have to send it to someone that can virginize it, then to my MB dealer for cloning because I assume virginizing is not something a MB Dealer does. If I jump all those hurdles and get a working ecu, then I can finally attempt the HP Tune update/hack. If any link in this chain of events fails, I think I'll just make my own circuit to control the boost solenoid and the ecu can f itself.

The oem solenoid boost valve cannot cause this issue, but I replaced it anyway, and I wanted a spare to modify. Remember, the ecu is actively controlling the boost to a lower psi. So it's not a hardware issue, unless some piece of bad hardware is telling the ecu to back off boost, but either way the ecu is ultimately doing this.

Thanks :)

Buy Chinese clone with no concerns about it! I cloned mine just fine. In the software you'll see instructions for specific ecu. Don't be scared, just do it. And get yourself solder gun just in case. I soldered my pins, no big deal.

Roman; you have a MED17.7.3? Because what I read said it can't do that specific model. Read only it said. Apparently it can do everything but that one. But if the chinese one can I'll try it.
I guess I have to buy a Bosch dealie to connect to the board, and that plastic stand to hold it right? That and a computer and I'm set, correct? I'd rather order it all at once vs one a time as I discover the parts I need. It's not like there's instructions or anything for my specific model, not that I've found.
And what's the deal with the Alienware Kessv2? Can that do the same thing and more? I don't understand what the difference is....
Thanks

I ordered a KESS, plus a bunch of BDM adaptors and the stand to hold it.
KESS because I read it's more for gasoline cars and KTAG is more for diesels and industrial equipment. So the KESS is supposed to do more cars, which will hopefully better my odds because neither the KTAG or KESS list my car, and the Alienware website saying it cannot write to my car. But I ordered it anyway because I'm desperate.

Bro I daily deal with these pcm's and I asure you it reads with ktag no concerns whats so ever.

MED17.7.1 and MED17.7.3 are the same.

same pinouts, same micro, same eeprom .. anything that deals with MED17.7.1 can definetly deal with MED17.7.3

I ordered it based on your confidence, and Roman :) It's on slow boat form china as we speak. est eta mid Feb. The ECU should be here tomorrow. I can't wait....

Wish I had known about this a year ago, or that other ECU's are compatible. Well, I hope it's compatible. I was using part # 278900130087, but apparently the 87 at the end is not important and dropping it opened up ebay opportunities. With ship & tax is was only $200! The place that refused me was $710, and another place that would sell to me cloned was 950. Plus shipping and renting a car for a week or more at $80/day + hassle was basically turning into a $2K ordeal. If this works it'll be more like $350 and no car down time. Fingers crossed, and the help I rec'd here is greatly appreciated!! :)

I use ME9.7. Mine was $250 with immobilizer and keyfob6(which i didn't use) and ktag from ebay for around $130 got it in 4 days, shipped from states. Good luck man, waiting on updates 💪🏻✊🏻

I looked for a source in the US but all I found was China and Europe. Clearly I didn't look hard enough.
Meanwhile the ECU showed up.

I have the KESS! So I was looking for instructions online, which is sketchy at best, as are the instructions that come with the unit which are not really correct.
I did manage to get it working and I read the used 2014 E63 MED17.7.3 I bought on ebay, but I have a few questions:
There is no selection for my car in the menu, but I'd imagine it doesn't matter as long as it's a MED17.7.3 because if I use the "Protocol" button it doesn't ask what car I have, you just pick "Bosch MD17 Mercedes"
I'm a bit concerned about the plug-in KESS asked for, which did not list MED17.7.3, only MED17.7.1 & MED17.7.8, so I chose MED17.7.1.

I have not tried the Clone function since I haven't pulled my ECU out yet, but I assume it's simple, like "Backup Read" my ECU, then "Write Clone" the file to the replacement ECU? Is that all there is to it? Then install the junkyard ECU into my car and drive away? No "Virgin-izing" I've read about. I don't know what that is anyway.

If there was a tune on the junkyard E63 ECU, will that stay in there and now I have it in my car?
Kinda the same question about my E550, do I do the backup with or without the tune in it, or does it matter? Because I don't know what all it's copying, is it everything or just the stuff that identifies it as my car?
I also don't know the difference between a "Reading" and a "Backup Read". The Backup Read file is slightly larger.
I'm off to pry my ECU apart...

Thanks