godrealm06

Took my car to the dealership today for schedule A maintenance. Was told car died twice in the bay. Couldn't find a reason why. Car needed a software update. Update done. Fast forward leaving work tonight. Turn on car and it just gives out. Turn it back on and it idles rough like it's trying to stay on. Car currently running rebellion piggy back for over two months. Zero issues. Any advice or input would be greatly appreciated.

godrealm06

Had to update the post to reflect new issues.

godrealm06

Update: On the drive home the gas pedal stops working. No engagement with the gears and the gears disappear off the dash board. Switched between comfort and sport to see if it'll reengage the gears did not work. When the pedal stops working car goes into neutral mode. Do not believe it's limp mode since you can still drive in limp mode. I lost complete ability to give the car any throttle. RPMs were still climbing when I did give it gas (just like when revving the car when its parked) it just didn't engage with any of the gears. Restarted car on the side of the highway and drove home. Gas pedal kept working and not working 10-15 times with sporadic idle. Only way to reengage with a gear was to tap the brake then hit the gas pedal. I'm a complete loss of what could be causing this. Checked under the hood when I got home. Saw nothing out of the ordinary. Did see a check engine light pop up when I pulled over on the side of the highway but the car gave no messages.

AV1

I'm no expert on suggesting a fix here but I'm very inclined to say you need to remove the tune and put it all back to stock and see what happens.

It could just be that from all the connections made for the tune one or more could be loose, shorting, malfunctioning etc.

There have already been a number of people experiencing problems after installation of tunes both piggy back and software remaps on the new M177 hence the above "possible" cause...

Also very curious when you had it serviced was the tune still on the car and if so did the dealer not mind

godrealm06

I had it on when I took it to the dealership. I don't think they even noticed. It's mounted in a way where by taking one look at the car you wouldn't even know if it's there.

godrealm06

I've already contacted Rebellion seeking input and did a few Google searches. Saw this same situation happen to several cars that have had some tune done.

AV1

Well there you go, it would seem possible that the tuning box installed may be the cause of your problems...

As before you may just have to take the time and effort to remove it, restore all the connections back to OEM and see what happens.

Hopefully the dealer installed software update hasn't added further to your problems since they were not aware of the tuning module obviously running and interfering interface with the ECU.

Good luck and certainly let us know what the problem was when its sorted.

vaelin

Your Rebellion piggyback came with a dummy plug; have you tried disconnecting the piggyback and plugging the dummy into the harness? That'll help identify if the piggyback is the problem or not.

GrussGott

Sorry for the tangential reply, but do you guys with these tunes feel like the benefit justifies the warranty risk?

vaelin

That's a very subjective question. It all depends on how risk adverse you are, and how much of the horsepower bug you have. If you're risk adverse and peace of mind of warranty is important to you, then.. no, avoid tunes like the plague and stick with bolt-ons.

Just my own thought process I went through:

1. Rebellion has had their piggyback tune for this for almost a year now, with a good number of piggybacks running out there. Granted, there's a few reported issues, but it's largely been an improper installation/failure of the harness. It IS a big pain in the butt to install; two sensors are pretty much installed 'blind'.
2. Current tunes are fairly conservative. Upping by 1-2psi. Well within the physical limits of the turbos.
3. Mercedes overbuilt the 4.0 V8. That much is a given, from statements directly from MB as well as the use of the engine in the AMG GTR and future 700hp+ applications.
4. I've got a fairly friendly dealer that I have a good relationship with, and where I've seen many modified AMGs show up for warranty service. Granted, blowing the engine/tranny because of an overboost condition will definitely not be covered. But see above #2 and #3.

Finally, look up the Magnuson-Moss Act, if you're based in the U.S. It protects you, the owner, from the manufacturer refusing warranty work on something unrelated to a mod you may have performed on the vehicle, unless THEY can prove it directly caused the damage.

Of course, with that said, if you use a tune and your engine blows up because you ran 20 passes down a drag strip... take responsibility and eat the repair costs. Don't try to pass it off to the manufacturer. In the end it hurts everyone in this hobby.

godrealm06

Found the issue. It was the piggy back. Was throwing a misfire code. Module became defective or something. Car returned back to stock and running like a champ. Will contact Rebellion about having it replaced. I did have it on for three months and I was happy with the piggy back. Putting it in limp mode did save my engine so the cars safety features did take over.

vaelin

Nice. Glad it worked out OK.

Where did you have the piggyback mounted?

godrealm06

Front left part of the engine. Behind the reservoir. It was mounted using double sided tape and strapped down with two zip ties.

vaelin

Ah. I considered there, but I was a little concerned about heat soak being so close to the engine. Ended up mounting mine behind the headlight, so that there was a bit more air gap.

PeterUbers

^^this x 1000

godrealm06

I've had an Evo prior to this with many protunes. I understand what it means pay to play. And the problem was identified. I'm not even raging on Rebellion. I understand **** happens. I just never encountered a situation like this and was concerned. I'll have them replace the unit I should still be covered under warranty. And it happened to be a coincidence that the day I drop it off at the dealership the car goes to ****.

PeterUbers

Not knocking you man, just appreciating another forum member's comment about tunes in general; glad your car is working well

Play on, pay-to-playa

GrussGott

Maybe, maybe not. The way the warranty works is you bring in the car, the dealership tells MBUSA the issue and details, that then they decide if they're going to cover it.

If you have engine troubles in the future don't be surprised if you're denied warranty work.

Just not a smart risk to take for me.

godrealm06

The warranty was for the piggy back. I've only had it for four months. Bolt ons and a conservative tune won't ruin your engine.

GrussGott

You have no idea if they will or won't and I'm sure you understand the irony coming from the guy who's just had engine trouble due to his tune....

But that's your 2nd concern.

Your first concern is that your dealership has noted your tune (or will) and, should your engine have any problem whatsoever, no matter the cause or reason, Benz will deny you warranty work. Now, this is the place where someone says, "but but but moss magnuson!"

However anyone that's been around the forum for awhile and/or corporate law knows that that doesn't mean shiit - Benz can deny warranty work at any time for any reason and it's up to you to prove they owe it to you.

Only there's a little trick with that: MBUSA is a master at this. Their core move is to delay delay delay which typically means about 2-3 years from the time of your first challenge until any judge hears any argument about your case. During which time you've paid legal fees and had the car parked. And, hey, maybe after 3-4 years you'll win that case.

The point is, you better fecking hope your engine doesn't have a manufacturing defect.

godrealm06

The bolt on options for this car is pretty limited at this time so I doubt having an exhaust with some filters will void your vehicle's warranty. I do know flashing an ECU will void any warranty. Once I flash the ECU I know I am on my own if the engine gets damaged. Also the dealership was unaware that I was running a remote piggy back tune. I wouldn't say I had engine troubles due to this tune which was in fact a piggy back system not a ECU flash. The ECU sent my car into limp mode thus protecting my engine so that there wouldn't be any damage.

jylee

I couldn't care less if MB fix and repair damage work caused by an aftermarket tune. One who tune and modify car should take responsibilities of their action. Take ownership and don't debate when your car need $$$ on damage work.

VaserC63S

These cars are complex, I will not be having mine tuned. I traded in my tuned BMW 335i with all sorts of bolt ons, tune quaife limited slip differential. My expirience with all that is that it was not worth it in the long haul and was a pain in the butt when something goes wrong. In my case BMW installed most of the bolt ons so they already knew from day one what was on the car. Luckily it ran with no major issues.

bgm130

while your dealer may be friendly MBUSA may have a completely different view of the situation. From the Audiverse we had a thing called TD1, so if a dealer hooked it up to a scanner and your car was tuned then you were flagged forever. That was not the dealers choice(unless they choose to not hook up ever). Per the bulletin that was posted dealers were also supposed to flag for anything modified (intake, suspension, exhaust, shifter). Once flagged MB USA would make a choice to pay dealers for repairs or not.
I am sure there is something similar to that with MB.
you have to realize these car companies are spending outrageous amounts of money putting military grade encoding on these ECUs. They know people will still crack it so they tuck it away so its not easy to get to like in the older models. They do this to save millions in warranty claims.
so its not so much what the dealer says its what they write into the MB system and then its no longer up to them. So long story short just be careful

GrussGott

yup, and FYI there's no such thing as "voiding" a warranty. What happens is, each repair and the details of the car are sent to MBUSA who then decides whether to pay for the work or not.

I've been around these forums and sports cars for a long time (15 years) and here's what I've learned for MB cars:

* There's a high probability MBUSA now knows about your piggyback

* Over the years a few forum members have gone deep legal over MBUSA denying warranty work when they had a piggyback tune, even though they'd removed the piggyback and the problems were clearly defects

* You won't see their threads anymore because part of the legal process was removing them

* None of them won and one guy went the distance: 4 years

* BMW is way WAY more forgiving on tunes, there most people get hassled but when they push back BMW usually pays for engine replacement

CONCLUSION

If you put on a piggy back or mess with your downpipes you have to do it with the expectation that Benz is no longer paying for warranty work. I wouldn't even do an intake with Benz - i.e., don't touch anything that touches the engine. Wheels, fine, exhaust, fine, cosmetics, fine. Engine bad.