skratch77

Been dealing with a slow car since I bought it guys. I scanned it with xentry and cleared all soft codes with no luck. I get about 75% boost and car feels like it has 375hp max. Trapped 114 mph.

I have it going into the dealership on Tuesday but I can see the same things they can with xentry and I need to ask them to change map sensors or see if the cooling system is working correctly.

Just a heads up you do pend codes with the blow off valves not connecting. I got crank case breather malfunction on both banks and went away when I plugged them back in.

tobeit

Never heard about that. You sure it's not something else but the vent not connected? Not sure how disconnecting the return and close the input to the intakes would be anyhow detectable to the system to produce a code. Edit: Or do you mean the electrical connecters not connected after replacing BOV with mechanical BOV...then you sure get a code.

skratch77

I'll drive it around some more and post back. I think those air quality sensors inside the intake are there to detect the boost coming back into the intakes

tobeit

not from all I know or all people here with open intakes would have the same issue including me. I assume when you take vent hoses off you plug the input to intakes properly?

skratch77

Yes they were plugged up. Have you scanned your car with xentry?

tobeit

No, I have not but drive around like that for weeks (and others likely for years) and nothing. If it would be a permanent problem due to disconnected BOV hoses it would become an active code. But others who know more about all that can chime in as I am no expert just doubt its due to venting BOV to air.

skratch77

There are lots of codes that pend in xentry and will never cause a check engine light or scan with a regular scanner. Like the low battery code.

the car will run fine with them and you wouldn't know they were even popping up in xentry.

AlexZTuned

The diverter valves are electronically controlled by the ECU, so unplugging them will definitely cause a fault (indicating to the ECU that one or both DV's are not functioning). This would more than likely put you in a soft limp mode that restricts power/boost until the valves connectors are plugged back in and the codes are cleared. A low battery/low voltage code may also put your car in a soft limp mode as well if you are not putting out enough voltage to power all of the accessories. I would make sure everything is hooked up (no sensors should be left unplugged, and if you have to, make sure you have a functional plug simulator to trick the ECU), clear all permanent/temp codes via OBD scanner (iCarsoft MB II or an Autel) or ideally use MB's Xentry if you have access to one.

Jimmy_c63s

Man something is definitely not right with your car at the moment. I remember a few posts you've made about the power not being there and how you're disappointed etc.

Your description of issues sounds exactly like soft limp mode. For me i couldn't hit full boost, car was slow and i couldn't break traction in 1st or 2nd.

Have you taken it to a dealer or anyone with an MB Xentry yet? We've gotta get this fixed mate 😕

skratch77

I have xentry and car is going to dealership tomorrow morning.

Maybe i just expected the car to be faster than it is.. the car was supposed to be on the dyno today but I canceled it.

Jimmy_c63s

How did you go today? Any updates?

skratch77

they said the car is fine. I loaded my stock tune when bringing it in also.

I will try to take the car stock to the 1/4 mile and see how it does. Also noticed my turbo inlit hose is cut up so need to see if a piece of rubber got sucked inside.

Car felt super fast with tune for a day then slow like stock or slower. Car trapped 116 ,117 and 114 with tune and filters and then the next week 116 with modal intakes. Bone stock c63s same night was trapping 118

FLC63s

So now I am confused... are you saying your car gets full boost with the stock tune ?? if thats the case, then its your tune bro... not a sensor, car, or engine issue..
What did the dealer do to determine its " OK " ??

skratch77

they said no codes etc. The car feels slow and will see what it traps stock. I can't say its the tune yet because it feels slow now also. Basically my car with a tune was performing what a stock car should run like.

Car also has a coolant smell that they said is normal? I was like no way thats normal and they said they pressure tested it and was ok.

Forgot to clarify i loaded a race map and on that file the carcwont make full boost. It put the car in limp mode and was the reason it wouldn't pass all monitors.

I'm going to drive the car for a little on stock tune to see if it goes into limp mode again then rake it to the dealer.

I didn't have enough time for the car to run on stock file before bringing it in.

FLC63s

I sometimes smell coolant (very little) when I am running it super hard .. but def no leaks etc..
I dont have any experience with a P31, so cant comment a ton, but if its not performing normal on stock, then going to a tune, wont assist it any at all..

I have to assume you are out of MB warranty or do you have an extended on it ?

skratch77

no I just told them i just got the car but they didn't say anything about if it was modded. I dont think they care anyways they just want to make money charging mercedes for the work.

FLC63s

So is this a different car then the one listed on your sig file ? the P31 (2013) or is this what we are talking about ?

skratch77

That was my old c63! I traded in for a 2017 c63s 22k miles on it and is a cpo.

FLC63s

ahh ok.. well then I can talk about it :-)

Chris McDaniels

I’m having the same exact issue you were having right now actually. Couldve sworn when I tuned the car it was quicker but after doing some testing a couple of days/weeks later the car is performing the same as a stock C63S is. I had exhaust flap codes that were coded out, still no fix. My car is boosting just fine but apparently its pulling timing for some unknown reason and after replacing spark plugs and coils still no fix. My car did have the crankcase code you had earlier but I believe that shouldnt effect the tune as much as we’ve experienced. Also I had a random knock sensor code pop up that I cleared. Nothing else is popping up in Xentry and after looking everything over the car just doesn’t wanna run properly.

Were you able to fix this or find a solution?

skratch77

I got a new tune from a different tuner and car is alot better but there are days its not as fast. I'm thinking the whole crankcase needs to be opened and cleaned and maybe there is oil everywhere in there from the return system..

I know modal works is making a oil catch can and that is what my next move is..