darkflash

Good day fellow MB owners,


I've done a lot of searching, but find myself needing input. Here's the situation:


Last week car started running rough while my wife was driving it home from work. Getting over 80 km/h was difficult.


Pulled codes via OBDII scanner and received the following:


P0015 - "B" Camshaft position - Timing Over-Retard Bank 1
P0025 - "B" Camshaft position - Timing Over-Retard Bank 2
&
P0300 - Random misfire
P0301 - Cylinder 1 misfire
P0302 - Cylinder 2 misfire
P0303 - Cylinder 3 misfire


Based on a lot of searching (this forum and others) it seems the consensus was the Magnets for the camshafts. Naturally I replaced all 4. Some were obviously not working as the center nub/very short shaft in the magnets were stuck, where as the new ones moved freely just by tipping them over/under.


The problem is that after replacing the magnets, it's still misfiring all cylinders on passenger side bank (1,2,3).


Both P0015 & p0025 codes are gone and have not reappeared, whereas all the previous misfiring codes keep coming up... and the car is still running rough...doesn't seem to have changed/improved since changing the magnets (solenoids).


Any thoughts on where to go next? Do bad 02 sensors throw a code for the M272? Some have said it could be a clogged cat, which could explain why only one side is misfiring. I understand that for it to be balance-shaft-aggedon, I would have to have 2 codes simulataneously
: P0016 and P0017 if I recall correctly.


Anything else to check?


Thanks in advance.

darkflash

Well in the absence of any assistance, I'll try and update my first thread on this forum in hopes it may help my fellow suckers, I mean, Mercedes owners.


So, went to the trouble of swapping upstream O2 sensors to see if the misfiring would switch to the other bank. No change.

ghenry

Please update as you troubleshoot the misfires. Curious to know the outcome!

darkflash

Sweet good Lord, it's fixed!


So checked plugs again and spark plug in cylinder 3 had a bent electrode! Other plugs looked nearing fouled, but were not wet. Changed all the plugs to NGK Laser Platinum and codes are gone, car is obviously running on all cylinders and is super smooth again.


I noticed the new spark plugs had a vastly different gap compared to the old ones. I don't have the history on my vehicle, but I understand(according to others on this forum) the early Bosch plugs had the wrong gap and have been super-ceded by another spark plug. So I feel good about dropping $140 bucks to change all plugs.


With the bent electrode in cylinder 3, there had to some pre-detonation in that cylinder.


My post-mortem guess - magnets/solenoids took a dump which then caused misfiring. One of the misfiring events were bad enough to bend a spark plug ground electrode into contacting the center electrode such that no spark could be generated. So replacing only the magnets fixed the retarded cam (lol), but obviously the spark plugs were damaged and needed replacement also.


Hopefully this is closed for now. Going to change the oil now.