SpecR

New to posting on forum but have been lurking since I picked up my 2016 E63S back in summer after bad experience with tuned Audi. I was holding off to tune or generally modify anything since I have an aftermarket warranty to 5yr/125k miles (now 66k miles).

Looked into tunes last month and had my heart set on paying more to go with RENNtech ECU upgrade. Decided to take a small step up to the R1 Package with diverter valve since the cost difference made sense for the gains. I had a good experience dealing with Patrick Casey at RENNtech over email and phone, then received my R1 Package with the Handheld Tuner, BMC filters, and diverter valve. Had the Weistec TCU tune come in as well, ordered around same time as RENNtech ECU tune.

Then had a reputable German auto shop near me put in the diverter valve and filters in for me so I know it would be done correctly. I picked up the car, checked under the hood to see clean install, and immediately heard the blow-off noise on high RPM let-offs. Everything feeling good, car still in stock tune.

Went home excited to get this thing flashed and out on the road. Brought out Cypher flash install from Weistec and RENNtech HHT. Did the HHT first, went red then green in about 50 seconds like estimated in instructions, all done. Then did the Weistec TCU tune flash and cleared DTCs, all done. No errors or lights on after starting, thinking good to go.

Start driving, instantly feel torque difference, especially down low. Took it to the highway after warming up fully, put my foot to the floor, car goes limp mode shifting from 4th to 5th. Dragged it to store parking lot, restart car, back to normal, no CEL or limp mode. Tried driving later with tune enabled, car would feel great down low and then oddly weak up top.

Took out my dragy and tested stock vs tune on same stretch of road, back to back:

Stock: 11.69 @ 120.76 and 11.82 @ 119.82 and 60-130 of 10.10
Tuned: 11.45 @ 117.42 and 11.64 @ 118.70 and 60-130 of 11.28

As you can tell, car was faster off the line but lost a lot up top, 60-130 is super noticeable. Was expecting around 11.0-11.2 @ 126+ in 1/4 mile and around 9.0 for 60-130. I've tried flashing TCU tune back to stock and letting ECU tune work by itself but doesn't help.

Emailed/called Pat from RENNtech and he sent data logger to see what issue could be. Sent it back and then later on HHT as well. They believe there is an issue with a stuck-open blow-off valve or wastegate control, possibly caused by PCV issue that lets oil get into the wastegate actuators. They say the car is able to reach stock targets but not tuned ones.

What confuses me is that if it is able to reach stock targets and not tuned, why would it have more power/torque in the low end and then be worse than stock up top? Seems like the tune almost contradicts itself in that sense based on what they are telling me.

Might be missing some details here and there, but bottom line is that the tune is good down low, sucks up top. Switching back to stock works perfectly, no changes with stock performance. Recently had battery disconnected for steering wheel install, didn't change anything either.

Looking for any type of help, advice, or experience with this. I know there's been a lot of documented experiences so anything to help would be greatly appreciated, whether by link or reply. Thank you!

Robert AMG

iTrader: (1)

sorry to hear that,
first before any tuning works start by changing spark plugs and coils.
when the car went into limp mode did you checked what fault codes has been stored on ecu?

PeterUbers

What did the logs say? Is it pulling timing up top in the rpm band?

what gas are you using? How much gas in the tank during the runs when it went into limp mode?

that new Bov is an extra variable that I wish you didn't have - would eliminate that as a cause.

when is the last time you replaced plugs and coils? I had timing retard with no CEL when I was in need of new plugs and coils even though stock was working fine the tune ecu was killing me up top like you. Eventually I got CEL's.

SpecR

I didn't get a chance to check any codes after limp mode, in hindsight that should've been the first thing I did.

Gas is 93 pump gas in CT, USA, always go to same Sunoco station. I'm almost never below half gas, but honestly do not remember the amount of gas in tank when it went into limp mode, happened almost a month ago now. Plugs were changed about 9-10k miles ago and 1 coil was replaced recently due to CEL, was stock at the time. I bought car at 53k miles and it's now at 66k miles, not sure what was done before that, don't have specific records. RENNtech did not send me any data from the logs. Based on what you're saying, it sounds like the plugs/coils might be the culprit if you had the same top end issue. Warranty covered the bad coil when I had CEL, but it might be worth getting a full set changed anyways. I do have a muffler delete as well but I can't imagine that having any negative effect.

Recommendations on plugs/coils? NGK plugs or stick with OEM? Change gap?

Thanks for responses!

PeterUbers

even with the tcu tune, the torque is still attenuated in first few gears - but not after 4th gear I believe - so the engine is making full power or trying to. Hence your issues possibly up top vs power from a dig.

stock plugs, stock gap. I run three ecu tunes with this and no issues; new plugs would be ideal - I change them every 10k miles; also new coils same time intervals. This could be as easy as your coils - do it yourself over 2-4 beers:

from the sticky on homepage of this sub forum:

https://mbworld.org/forums/w212-amg/...s-vrodman.html

And the sticky:

https://mbworld.org/forums/w212-amg/...-w212-amg.html

SpecR

Going to order both right now and cross my fingers. Thanks for your help!

Freedomvango

weird. I also have the R1 package and haven't experienced the same issues. about 2 months now

JohnLane

OP when charge temperatures go UP due to more boost it will pull timing and boost. If your charge coolant pump is not fresh replacing it is well advised. Also.... it will make a LOT more power in lower ambient temperatures. I’m in Phoenix where there is easily a 150lb/ft difference between January and August. Additional heat exchanger and more charge cooling capacity is on the list for my S-65. Best wishes increasing the smiles/mile via enhancements.

SpecR

Went with RENNtech for the reputation, they have a great track record, I'm just hoping it's a simple fix like the coils/plugs.

If the coils/plugs replacement don't help, I'll look into this... thanks for the advice!

PeterUbers

thread re: IATs, and IC pump failure causing timing retard (also from sticky); that's why the logs are important to know what they showed and how the timing and potential knock, IATs, fuel trims etc are all behaving at WOT.

https://mbworld.org/forums/w212-amg/...an-logs-3.html

billvp218

Most m157 cars here who datalog do so with HPTuners, as far as I know. It's $400 for the OBD2 logger, and the software logging suite is free with the logger purchase. https://www.hptuners.com/mpvi3/

If you log each of the setups (stock, TCU only, ECU only, TCU & ECU), and post the logs, we could tell if something looks screwy.

SpecR

Sounds good, I’ll see if plugs/coils change anything, then get the logger in case they don’t and for future use. Thanks!

The1stWright

More than likely coils and plugs.

Before you throw another set of plugs in double check with renntech about the gap.

amg guy

iTrader: (1)

I've run their R1 tune on two of my cars no with no issues.

I'm betting at 66k miles, your coils and plugs are the culprit. If they are both stock they NEED to be changed.

SpecR

UPDATE

Just had the coils and plugs (.022 RENNtech advised) replaced... 0 difference.

0-60: 3.39
1/4 Mile: 11.58 @ 117.08
60-130: 11.25

I know the next step is to get the data logger and provide logs on here and to the shop, but man... the reason I paid the "RENNtech tax" was so I wouldn't have any issues with the tune... just wanted plug-and-play, simple and easy.

Any cheap or quick suggestions to check before I inevitably give in and get a data logger? Appreciate all the responses, thanks.

PeterUbers

but no more limp mode?

one thing to try is add 2 gallons of e85 to your 91 or 93 octane, let it mix for 10 minutes of driving and then hit the dragy again; 2 gallons of e85 with 15 gallons of 93, that is -- the tank will be mostly 93 you are just increasing the octane

SpecR

Only had limp mode the one time, never happened since. Also, shop that did the plugs and coils said no trouble codes at all.

I don't even know what to do at this point besides data logger, but I didn't really want to go down another rabbit hole like my previous tuned cars...

I could add E85 but closest stations are far from me (CT) so even if it helps, I wouldn't be able to repeatedly add. Unless you think there's some benefit in doing it once? For testing purposes?

Robert AMG

iTrader: (1)

2- change your fuel quality like Peter said
3- get a cheap obd (10$) with Torque app and check air intake temp if you don't want to pay for hptuner
4- check engine cylinder compression
5- change tuner.

GinDistiller

Try getting an iCarsoft MBII, they are about $150 and can access a lot of Merc-specific modules. The best feature though is you can see graphic data on several OBD2 channels, so you can do a run and then see the graph of boost, timing, air intake temp etc and see if anything is amiss. It doesn't 'log' and save the data, but it's plenty for some on-the-fly diagnostic work and has solved more than enough strange issues for me on a few different AMGs.

PeterUbers

Any 100 octane near you?

the issue is - is the ecu pulling timing of detonation to prevent knock/misfires because of a problematic variable - high IATs, poor fuel octane, lean fuel condition, poor ignition from spark plugs (but these replaced so not this), -or- you're not making boost for whatever number of reasons

- all of this is beyond what the engine needs for stock trim. If your engine is in proper condition this should have been a simple tcu and ecu upgrade story without any issues like this.

if you could get one variable off a cheapie obd dongle - I would wanna know IATs first ... then timing retard (if any)

SpecR

Considering the car works perfectly in stock tune, I don't think the gas or compression test would make much difference, but I could give it a try. I already have the diverter valve and filters installed from RENNtech, would they even refund the difference for the HHT if I decided to change the tune?

iCarsoft MB II specifically on Amazon is sold out but I see these other two ones. Amazon has the fastest shipping I could see which is only reason I'm looking there.

Would either of these serve same purpose?

SpecR

I'll get a scanner/logger and try to figure it out. The annoying part is that the car is great in stock form, so I'm doing all this to solve a problem I guess I caused by getting the tune... I just don't want to give up and do it all for nothing...

PeterUbers

I mean if I'm not mistaken renntech already said you have a wastegate, pcv, or bov issue ...a boost issue

im surprised they won't send you the logs, they already have your money/business ...

SpecR

I might have the shop that installed the diverter valve check it over and make sure it's doing what it's supposed to, but still doesn't make much sense to me that it wouldn't affect stock tune if it was the diverter valve causing issues.

Let me email RENNtech and see if I can get logs from them.

Another issue with the logs is that the car ran even worse during the logs, so I wonder if the problem can even be narrowed down. During the tuned log, it felt like it had half power. Of course, that was the only time it ever acted like that, during the most important time.

PeterUbers

can you block the BOV or deactivate it to see if it'll allow then engine to make full power (given that it's the issue) ? The shop can do this for you