ktos92

Hello Everyone. I fighting with missfire on my W215 CL600 with M275 engine. In short what I have done it:
- replaced two ignition coils
- replaced ignition voltage transformer
- replaced spark plugs
- checked fuel pressure around 3.8-4 bars
- replaced one O2 pre cat sensor
- replaced pressure sensors upstream and downstream of throthle body

I am having random missfires on cylinders 10,8,7,6,5,2
The most affected cylinder is number 10. Missfires are happening straight after engine start. Engine is running rough and you can feel it shaking. When you drive it seems to be smooth unless you will try to push it hard then you will get check engine light and engine is running very rough. Restart usually helps. What else can cause the missfire? Can it be injectors, bad fuel filter? Engine has around 60 000/70 000 miles and we have the car since 7 years. It hasn't been abuse and always service every 6 000 miles or once a year.

MrTracy

Did you replace the coil packs with new or used?

ktos92

One of them is reconditioned by Clark from V12ICPack and the other one is brand new on cylinders 1-6. Clark checked igntion coil on cylinders 7-12 and voltage transformer is well.

slonar21

I had a similar problem, read here
https://mbworld.org/forums/m275-v12-...elaration.html

ktos92

i was thinking the same. I have read your thread before. I checked fuel pressure and at idle I am getting 3.8-4bars / 48-55psi
Engine missfire just after start is well.

HopefullyE63

First thing I did to my 2003 v12 was to order both coil packs from V12icpack and one of them gave out. I'm sure it was installer issues but still. See if Clark can get you another coil.