snowmuch

We swapped the 7,8 coils with 3 and 4 and still getting misfire on 7 and 8. I didn't look at the codes but I think others went away. Will try with new filters and new MAFs tmr.

Ingenieur

Sounds like it might be drying out?

snowmuch

With with MAF connected it sounds like its suffocating and cars will shuts off due to too many misfires. With MAF disconnected it sounds just very shaky.

Ingenieur

Did you notice any moisture on the coil or maf connectors?
Did you clean/dry them before reconnecting?

snowmuch

There was burst of moistures when I was unscrewing the coil but the inside is clean and dry.

ToXicXxX

The coils were bone dry, no dielectric lube left on them. Plugs 6-7-8 were soaked in gasoline (which makes sense with the misfires), others were extremely worn out. Code P0010 appeared sporadically (indicating a possible failing cam solenoid). After plugs and coil swap, only 7/8 were giving codes as well as "random misfires".

It was actually misfiring so bad it would stall, on several occasions. Looking at a few possibilities...

snowmuch

There is a bunch of people having cam solenoid problems in their c300 not sure it shares the same part with c63

https://mbworld.org/forums/c-class-w...-campaign.html I member lone star doing the same thing with my tail light and engine wiring recall.

Ingenieur

So everything cleared up but misfires on 7 and 8 + associated random
You eliminated the plugs and coils as the issue
And a random a cam code?
Try cleaning cam sensor and solenoid connectors?

Just seemed like a lot of water in the airboxes
Perhaps the random steering, heater, etc codes were generated when voltagecwas cut due to the misfires?

Sounds like you got a plan
Let us know what you find
Thanks

ToXicXxX

I believe those are old collective codes, his car hadn't been cleared in a long time.

We can pull and clean the solenoids (similar to BMW VANOS cleaning), but, theres a few angles of attack here.

We will attempt testing my spare MAF sensors tomorrow and see what that yields.

It doesn't seem the parts are shared between the C63 and C300, at least via partnumber.

PeterUbers

Man, I wish I knew as much about engines as you guys, I'm impressed!

ToXicXxX

Eh, for me it was a hobby turned job! Let folks like us tackle that crap for you!

papashango

Haha have to agree with Peter. Most of this jargon sounds like French and is flying over my head. Another reason I don't want a car without warranty. lol Thankfully there are guys like Toxic around who can deal with this sorta stuff for us lol.

Merc63

Sounds like a fueling issue and not a cam issue. Plugs soaked with fuel, runs better with maf unplugged...

Cam would cause issues on the whole bank.

Try new o2 sensors and make sure plugs are good.

ToXicXxX

O2 sensors would also be a bank issue, not individual cylinders.

If you look at the firing order on the M156 it is 15426378. The 7-8 misfire is the end of a complete cycle. Perhaps there is some merit in that.

Merc63

Not necessarily. I've seen misfires on just a few cylinders when others will Fire.

ToXicXxX

Fair enough. I've never encountered an O2 sensor giving issues without generating a code.

Ingenieur

Let's summarize
New plugs
Coils swapped so not coils
Only codes are misfire 7 & 8 plus the associated multiple code
All others cleared
Where are cylinders 7 & 8 physically located? Rear most driver side?
Do 7 & 8 random or consistently misfire?
Do they misfire with the maf disconnected?

Was the fuel tank run low or dry?
Plugs are wet so it is fueling correct?
Did you check for spark?
Did any of the 'mud' get downstream of the filter?

ToXicXxX

7&8 are by the firewall on the drivers side yes.

No mud downstream, though we can't tell for sure without removing the IM.

Next step is a compression test to see if everything internal is healthy.

Curiously the fuel injector on 7 was slightly deformed around the outer housing. Nothing major, but. Notable fact.

It runs slightly better with no MAF, but testing a spare set of air boxes and MAF's yields the same results (and those MAF's work fine in my car).

SROC276

Just curious? What was the final result?

snowmuch

It was the lifters. I had the entire engine swapped to a facelift one with no lifter or head bolt problem.

SROC276

Goti it....thanks for posting