Hey guys,

I own a 2012 C63 AMG with 130k kms on it. Had oil changed before storage. Has not been daily driven since November 2019 (Winter here in Canada) and is being stored in a garage.
I have been starting it (couple times every 1-2 weeks) and letting it run for a bit.

Before running it one day I plugged the OBD2 scanner (Innova 3100j) and got P0300, P0303, P0304 codes. I erased them and ran it again and then just got P0300 (Random misfire) and P0304 (Cylinder 4 misfire). These are permanent codes. (If I understand correctly, the permanent codes will only be taken off once the computer reads the problem has been fixed?)
From my understanding, assuming I am facing the front of the car, cylinder 4 would be the back left (which is on passenger side). Unfortunately it's not easy finding the cylinder chart but I read this somewhere that this is the case.

I then started it and it was running a bit rough but nothing crazy.
So I started with a simple coil swap to see if it was a bad coil. This did not change anything.
I then pulled the spark plugs to see the condition. I have no idea when the spark plugs were changed last but attached are pics.













These are plugs from cylinder 1 and cylinder 4.
From looking at them it seems like fuel is running rich. Given the discoloration of the ground electrode does it seem time for new plugs?

I already ordered 8 new NGK ones, I figured it wouldn't hurt to but new ones in.

When starting the car I also noticed more smoke coming out of the passenger tailpipe (which would be the side with the misfire) compared to the drivers side. I believe there must be some sort of correlation between the misfire and smoke from tailpipe.

My next step would be to change the O2 sensors, also something I believe have never been changed. Given the KMs on car should I change it anyways?

Another thing I noticed that took me by surprise is a little puddle of coolant on the drivers side floor. I haven't had time to look into it but i find it extremely strange.

Any help would be extremely appreciated.

Thanks

 

Get some fresh fuel and go drive the shît out of it.

 

Cylinders 1-4 are on the side where the pcv is and is where most oil builds up inside the manifold. Willing to bet its just oil that drained down and is causing you miss fires.

 

did you figure out the cause? I'm having the same issue and changed my coil and spark plug but can't plug my coil all the way into the harness for some reason.

 

I'll be working on car this week. I'll provide updates.

 

I have stored cars (including the E55) from time to time for more than four years. Always with copious amounts of fuel stabilizer added to a full tank and then driven normally for at least thirty minutes which eliminates moisture from condensation. Then finally placed on jacks with a battery tender. In Germany the 102 (RON) octane fuel is ethanol free. In America I use a stabilizer such as Startron which prevents phase separation.. Never a problem.

My suggestion is once it's stored, don't start it until you're ready to drive it again.

 

Hello everyone,

Thank you all for the feedback, greatly appreciated.

So before changing the spark plugs out. I decided to start with Jasonoff's idea. I filled up the tank completely, got the engine temps up, and went for a spirited drive (man did I miss that M156 AMG power).

Before the drive, I verified how to get rid of permanent codes on OBD2 scanner. Link https://www.autoserviceworld.com/car...ermanent-dtcs/ says you need to do a "universal trip drive cycle" which is:

"...turn the ignition ON, start the vehicle and let it idle for at least 30 seconds. Then, without cycling the key, drive the vehicle for at least five minutes at more than 40 km/h. Then (again without cycling the key) let the vehicle idle for at least 30 seconds before shutting it OFF. The whole drive cycle must take at least 10 minutes."

At end of my drive, all permanent codes were gone and no issues at idle as described in first post either.

I'll update if anything arises in future. I have decided not to install the new spark plugs I bought since codes are cleared. However will probably change them sometime within next few weeks anyways.

Thanks guys!

 

Hey tai rahmaad, have you tried adding a bit of dielectric grease inside the boot of the coil?

 

​​​​​yes.... Last night my dash lights began to light up as if my battery is bad. So gonna purchase a new and see if that solves my issue.... Had the car stored no trickle charger.

 

Our cars are very sensitive to battery condition. I accidentally killed mine, (my own dumb fault), and I had 47 codes to clear when I got it charged back up.

 

I agree they are sensitive.... But the battery should do it though.. Keep you posted!
.