I just bought a 2015 c63s edition 1 with 49k miles on it, the car has Weistec downpipes and air filters, AWE switch path exhaust, ECU relocated, and a tune

i bought the car from Boston and I went there and checked the car and haven’t felt any loss of power because it was slipping due to cold tires and streets.

Had the car checked by Mercedes Benz of Burlington and everything was great they say. I shipped the car to Arizona and raced my friend who has the same car but stock which I should beat him easily but the opposite happened which he pulled away by at least 1/2 mile distance.

I took the car to the dealership which they haven't found any codes or anything wrong. They did a fuel pressure test and it was good. After further inspection they have found a kinked vacuum line that goes to the turbo waste gate which we thought that its the problem and they changed it but, that didn’t fix the issue!

As the old owner told me the car was tuned by Renntech which i found out that they didn’t tune this car which they verified it with the VIN. Tried to talk to the old owner to see who tuned the car so i can reach to them and see if something is wrong with the tune but, he started talking to me in a Sh** way and then blocked me! So now i don't know who tuned it!

Can someone advise me on what to do, or should i let the dealer flash it back to stock tune which they think might cause more problems to the car.

I attached a pic of the car someone might recognize it and maybe knows anything about it

**UPDATE** contacted Go auto repair today who worked on the car and they told me that the car is tuned by a guy in New York named philip or phill dose anyone know him or know the name of his shop

 

I do recognize that car, i believe it was tuned at go auto repair in nashua nh, i believe it has an amr tune

 

You are lucky dealer still willing to help troubleshoot the issue. out here once they know you have tune they void the warranty right away. I would say let them flash it back to factory tune.

 

The first thing to do is to put your car on a dynojet to find out the actual horsepower it's making at this point, the stock car makes around 450 wheel horsepower, and you should get a number around 530 ~ 550 whp since it's tuned(I assume it's a regular Stage II tune).
If your car is making less than 450whp then it's definitely not normal.

You may start by getting your engine cleaned since it has passed 49K miles, too much carbon deposit will rob your horsepower, M177 engine has direct injection, that means the backside of the intake valve has carbon deposit that cannot be cleaned by regular fuel injection cleaner. If the previous owner didn't care much about the car, then you should do this, trust me, you will get a lot of power gain after cleaning. (This should be done every 20K miles or so)

The next thing is to take out the airfilters to see if they're cleaned or not, and you also need to drop your engine and transmission to clean the intake manifolds and all tubes that turbocharged air goes through.

Then you should make sure your tires, especially the rear ones have enough tread width left.

After you finished all the steps mentioned above and your car is still slower than the stock one, then you should contact the tuner to get it retuned, if you don't know which tuner he used, just contact several of them, give them your VIN and let them find out.

 

thanks for the information, will contact them hopefully they can help

 

Just flash back to stock... You'll get a CEL from the downpipes but that won't cause harm... Then buy a new ECU tune and flash that... Good to go!!

 

Could it be shipping mode? Since you shipped it through states

 

I guess that would be my best option if AMR said they didn’t tune it

 

what is that shipping mode ? I haven't heard of something like that before

 

Transport Mode (shipping mode) is used by the factory to put the cars into a "sleep" mode to conserve battery charge during long periods of inactivity. Normally under transport mode , power output is limited. Each type of car has its own procedure to activate/deactivate transport mode.

 

I didn’t activate the Transport Mode when I shipped it and if it was something like that the dealer would have known about it

 

kinked vacuum line?

 

thats what the dealer found and they replaced it but it didn’t change anything the car still has less power

 

Wow that sucks man. And the way that previous owner is behaving leads me to believe this car had some underlying issue that could be the reason he sold it. Hope it works out for you OP.

 

Plz switch your dash to see the boost. manual mode and lock 4 or 5 gear. from 2000 rpm Full throttle. If after 4000 rpm is not full boost. I know the issue. If boost is still full. we are not same issue. Cannot help you

 

Will try that today and will let you know

 

Flash it back to stock. and race your friend again and them take it from there.

 

I would flash it back to stock first, then try to figure the problem out