C63sydney

I know this has been discussed before but I want more discussion on the issue.

I had a drag day the other day and had issues with the car in S+ Mode Traction completely OFF the car would occasionally cut all power for a second in first or second gear after wide open throttle.

I have an OE Tune on the vehicle and secondary cat delete.

Ever since the car was stock it would occasionally be reluctant at HIGH Rpm say 5.5-6k RPM and cut a little power now with the tune it seems it engages this abrupt loss of power mid to high RPM.

Even around town the car when pushed reasonably hard will cut all power.

It doesn't seem to be mechanical as there are no strange noises and seems to come from the electronics of the car.

This is my 2nd C63 and my first wouldn't do this.

Any history of this issue or technically minded advice much appreciated.

PeterUbers

Have u gone back to stock ecu to see if it does the same thing

C63sydney

No I don't believe the tune itself is affecting the power cut only if the torque levels are so much greater that the computer decides to shutoff power to the clutch or trans engager of some sorts?

Mercfan64

I don't think shutting off ESP disables stability control. If the car senses a spin out of control it will brake or cut power.

AMG893

What year is your car?

C63sydney

10/09

C63sydney

Bump.

Has anyone had issues with intermittent issues with alternator? I am not getting any Codes come up.

I changed out the K&N Filters thinking it could simply be oil on the MAFS but after a month with stock filters still have the issue?

Thoughts on what it could be;

1. Bad spark plug? The car is now 4 years old.
2. Transmission issue? The car has only 34,000km on it.
3. Bad injector? Would seem to throw a code if it was.

avery.whss

fuel pumps ..100% just went through this exactly, have fun waiting 1-2 months for them though from germany luckily they are only 700-800 a pop, you'll need 2 + the fuel filter...the car will run like brand new when it's fixed, the pumps won't make a noise either..it just cuts power hard between 5-6k RPM

C63sydney

Can you elaborate on how you know this is the same problem you had?

Thankyou

avery.whss

exact same symptoms at exactly the same RPM range, thats how I know...take it to MB and have them put it on the computer..it takes 5 minutes and is free...$50 says you have low fuel rail preasure which means you need 2 fuel pumps..how many KM do you have? I have the exact same setup too..OE tune/2nd cat delete...eventually it'll go into limp mode whenever you push past 5k+ but the car will still run, it'll just be insanely loud if it goes into limp mode, it's like it pushes all the exhaust note out 1 side instead of both

Luckily the pumps aren't even that expensive...$700-800 a piece which is reasonable seeing my sisters ford conturs pump costs $300 and its from the 80s

AMG893

Had this problem on my ML63.
Luckily i have Star Diag so i ran it, and yep, fuel rail problem. Same symptoms.

ToXicXxX

You're car doesn't have S+, because it's pre facelift. You have the automatic transmission.

If you suddenly lost power it is probably stability control, or a K clutch is starting to slip.

C63sydney

@ AVERY.WHSS Thanks for the advice will drop by merc to check fuel pressure.
@ AMG893 So what was the outcome or remedy did u replace fuel pump or rails?
@ToXicXX I meant S+ as in Smanual mode so S1.