If you didn't get new spark plugs and have them gapped, you're going to get more check engine lights. Renntech uses factory plugs from Mercedes and gaps them to .022 instead of the factory gap of .028.

As for your last sentence, I think "Nice Ride" was asking what you meant about that... It sounds like you're saying you can't take-off slowly in first gear without the car bucking? Do I have that right?

 

Lol when people actually think you have "zero worries" when getting a Renntech tune. No tuning is officially backed by merc, the closest thing you can get to a warranty is with AMR and eurocharged, and that's their engine warranty, that they themselves supply. If you have a catastrophic powertrain failure, no one is gonna pick up the tab but you, not Renntech, not Mercedes.

 

You have to laugh when you clearly state something and then someone asks a leading question saying the exact opposite of what you said??

Its very simple here guys. You see post after post about tunes voiding your warranty and that MB will refuse service if you have one.


Your making my point, MB still covers the car and there would be no reason for Renntech to cover anything but I have full faith that they would assist me where needed. Its easy to post that a Co would pay for your engine because they know how are you going to do that?? That is why having a tune that doesn't effect your existing FACTORY warranty makes it worth what they charge.

In the end you choose whatever you want and makes you happy all I am saying is what happened when I did have an issue. As far as the plugs your wrong and passing along wrong info. That does not apply to MY tune. I have spoke with Weistec who on their tune which is almost double the HP does need the plugs changed. Read my initial post it is the lesser 91 tune. Your applying what is needed for a different mfg's tune.

Stop trying to be the guy that "CATCHES" something that doesn't exist.

In "SPORT" even without the tune if you lift in the middle of a full throttle acceleration you feel the car buck with the tune in first gear you cant lift or you will get a bucking feel to it. Again that is only full throttle acceleration and doesn't effect normal driving. In my G Wagon it was even worse with the 4wd. This is why I didnt get an S63 it was ridiculous to drive for such a big luxury car although I believe later models have gotten better.

Not hear to argue with anyone I'm stuck at a computer and wasting time waiting for a client not to get in a pissing match. Choose who you want just passing on info that obviously doesn't apply to you. I never stated anywhere that Renntech would pay for anything, call them not me and ask.

 

Okay, so the only issue you feel/see is that when you floor it in first gear, and then let off, the car bucks without the tune - but WITH the tune - it bucks even if you're not flooring it?

 

Im going to assume you have a reading issue and move on.

Have a great day!

 

You said, "In "SPORT" even without the tune if you lift in the middle of a full throttle acceleration you feel the car buck with the tune in first gear you cant lift or you will get a bucking feel to it."

What you said doesn't make a lot of sense. You get the buck in SPORT without the tune and you get the buck WITH the tune. Maybe if you were a little more descriptive with your writing I wouldn't have to ask for clarification. It's not my reading comprehension that's the problem here. It's your inability to form a complete sentence and make sense.

Let's eat Grandpa.
Let's eat, Grandpa.

edit: Are you saying that you get the buck in sport mode in ANY gear without the tune - but only in first gear WITH the tune?

 

Dabronx, we all appreciate the information you are posting on the tune. My questions on calling RT when the misfire/check engine came on was only a question. In general I guess most people would agree that a misfire is very rare in the S. If I did the tune and had a misfire / Check on the display, I would of first called Rentech as they are familiar with what may occur with the tune and make suggestions / recommendations. It is true that some dealers may not have an issue with the tune on your car, but, I am pretty sure if you damage your Trans or any other major item, it will be the pure discretion of MB corporate, not the sales / service manager. Now if you have a great relationship with the dealer and they installed the Tune ( Some Dealers are Certified to install / Sell the Rentech tune, they may overlook what they put on the paperwork up to corporate to get your new trans installed. Now Rentech may assist with working with the dealer, however at the end of the day, it is purely MB that will approve / disapprove the major repair. I do appreciate your honesty in the Good and the Bad of the tune and your personal experience. It all adds to why the forums exist. To a degree other responses in general are from there personal experiences without getting into the specifics and in a way are a general answer. For the most part, I don't think the responses are negative or against your decision, we are just digging to get more information on the responses. I personally do know that if a MB Dealer finds out a tune is on the car, they WILL mark your VIN in the system and it will stay on the car for ever unless it is removed, purely the dealers choice. In my opinion, I would have removed the tune before bringing it to the dealer, if I were playing the odds, that's my bet. I personally think you got lucky with the dealer, but, because you informed them about the tune, they may have marked your VIN, in my opinion, if you blow your tranny while under warrantee and your Vin is marked, you may not be so lucky with the warrantee.... Again, I personally are appreciative of you posting in information. Less is more, remove the tune, bring in for service, then out it back after and hope it does not happen again. Could have been simply because of bad gas from a station.

 

Hi Dabronx
I had a tune done on my 2015 S550 a couple of months back, the difference in power is very noticeable, the only issue I have is when braking it is not smooth, feels like the calipers are sticking
I have new rotors and pads all around and even switched back to the factory tune and braking is smooth again
Could you tell me how your braking feels with your tune
Thanks for any info

 

No braking issues at all. You have me stumped on that one. So when you get on it and go to break the brakes freeze up?

The tune would have zero effect on brakes but maybe your feeling the effect of something the tune is causing.

Be a little more specific of exactly what happens and when.

Call Renntech they are super helpful!!

 

Yeah sorry I should have said I got my tune from OE Tuning 93 octane
The braking issue happens at even normal driving conditions, low speeds in city driving, it feels like a rough downshift/jerk, hesitation, takes longer to stop
Once I uninstalled tune, the brakes stop smooth and normal again
I contacted OE Tuning, they said they recommend I do a transmission software update from dealership as it solved similar issues for other clients that had their tunes

 

Sorry but this is why I use Renntech. They do serious testing and driver a safe no compromise tune. With turbo cars everyone thinks they can tune the car, turn up the boost. With Renntech your paying more for their wealth of knowledge and a well tested product and most importantly a Co that doesn't just ansswer the phone but solves the problem!

I can only assume your not used to driving a turbo car where the boost has been turned up as once your on boost the car gets moving fast and builds and builds and builds so if you stomp on the gas and then try and stop in mid boost it feels like the car is getting away from you. This is why in 1st gear launch you cant just let off without the car reacting with a violent bucking. Try launching in 2nd and see how it feels. Honestly I think your lifting vs staying in it and shifting to the next gear.

These cars are making monster power and they are dangerously fast and powerful. These aren't the old MBenz's that were kind of quick. An S63 is F'ng fast!!!!!

 

Well I uninstalled my tune back to factory for a few days and then reinstalled the tune and the braking issue seems to have gone away, stops much smoother with no hesitations or jerking, im not sure if something happened with the download the first time I installed it with the handheld programmer, but fingers crossed the issue is resolved

 

Is it possible the tune is holding the gear longer and that is the sensation you are experiencing?