w208 m112 misfire when cold p0201 p0301 odb2 codes

Page may contain affiliate links. Please see terms for details.

dolla

New Member
Joined
Nov 26, 2013
Messages
8
Car
clk320 w208
Hi all first post so please be gentle, I bought a clk320 cab (w208) in august and everything was running fine, at the beginning of november the car started to feel lumpy. After reading this forum for a few days I decided an odb2 scanner was essential to find out what my problem was, got a bluetooth scanner and torque app codes showing as p0301 and p0201 (misfire cylinder 1 and injector circuit cylinder 1)

I have since (with lots of help from this site) changed the air filter , spark plugs(old ones were in decent condition, no cracking, looked clean not oily and no real signs of wear, swapped coils and leads separately to see if misfire followed with no luck, I've also changed cps as old one was filthy. I have also checked my MAF it was as clean as a whistle and the readings are 4.5g/s at idle peaking to around 50g/s at peak acceleration (is this right)

Once the car is up to operating temp about 87c if I stop engine and start again the misfire is no longer there and the codes eventually clear ready to return when I start from cold again. Would a faulty/dirty injector start working when warm? Or Could this issue stem from coolant temperature sensor or thermostat.

Please help mbclub you're my only hope. (Btw sorry about all the brackets )
 
Went for a drive with odb2 live data running and could see that when stationary the coolant temperature would rise albeit slowly. When moving I could see the coolant temperature dropping, it took 20+ minutes to rise to 87C and when I restarted my car and the misfire was gone.

I am going to change the thermostat on sunday unless someone can see another issue it could be. I have found a how to on pelican but I am a complete novice so any tips would be really appreciated.

Everything I've tried has been thanks to posts on this great forum and even though my cars not running right i‘m really enjoying learning about these amazing cars.
 
Drain off the fuel rail first. As they have no return water can build up at one end of the rail and cause number one to misfire.
 
Thanks for that blackc55 just tried it now with no luck. I took about 300ml out of the schrader valve is this enough .

cheers
 
Also drain the fuel filter into a jar to check for water, not seen one for ages but years ago seemed to be quite common, tended to cause misfire/hesitation when hoofing it as the water in the rail (if any) shot to the back of the rail.
 
Went for a drive with odb2 live data running and could see that when stationary the coolant temperature would rise albeit slowly. When moving I could see the coolant temperature dropping, it took 20+ minutes to rise to 87C and when I restarted my car and the misfire was gone.

I am going to change the thermostat on sunday unless someone can see another issue it could be. I have found a how to on pelican but I am a complete novice so any tips would be really appreciated.

Everything I've tried has been thanks to posts on this great forum and even though my cars not running right i‘m really enjoying learning about these amazing cars.

How did you get on with changing the the thermostat?

I would say that taking 20+ mins to reach 87 is far too long as you want the engine to warm as quickly as possible. I had this issue with an old thermostate and as soon as I changed it the car heated in mins even when its icy outside my car is warm in about 4 - 5 mins ! Also my MPG greatly improved too !
 
Just changed it about an hour ago, ran it up to temprature, cleared codes and started it ..misfire was gone. Just need to leave overnight and start from cold to see if they return. Fingers crossed although I would be surprised if misfire completely cleared. If not i'll be swapping injectors around to see if misfire follows.
 
Just started it up and the misfire is back….. gonna look at fuel filter tomorrow see if any water in it, if anybody else has any ideas I would be dying to hear them as I am about to run out of thinks to check
Cheers
 
Set off from work and engine definitely warmed up quicker and misfire went away reset codes and drove home just as I arrived home CEL came on and misfire started, so I ran code reader and same codes came along with some New PENDING codes p0003(Powertrain random/ multiple misfire detected) , p0300 (powertrain) and p0100 (Mass or volume Airflow circuit). Hopefully someone can shed any light on the pending codes, And how important these are (should I clear them then go for a drive and see if they return)

Is it still worth looking at the fuel filter and injectors

Again any suggestion is welcome as this is all new to me
 
Cleared codes went for drive and guess what CEL light came on checked codes and 3 new fail codes p0100 p0101 and p0103 so looks like a new MAF, seen a bosch one on ECP for £140 is this the going rate? Does Anybody have any discount codes as I'm a tight ar*e
 
It looks like I've finally sorted it, ordered a used fuel rail with 6 injectors of ebay for 70 quid got some new mercedes benz rubber o rings (£2.75 each :eek:) and swapped out number 1 injector with help from the pelican guide. So far so good all sounds sweet. Thanks to this forum I've saved a shed load of cash and got a lot of confidence to work on my car… .cheers
 

Users who are viewing this thread

Back
Top Bottom