Misfire on Cylinder 2

[Usheruff]

Hello everyone,

I'm driving w203 c200, M111 engine.

I had done several test but misfire on Cylinder 2 remain the same (no spray):

1. swap ignition coils.
2. swap fuel injectors.
3. wire harness have power and i'm using test light only.

Faulty code :

1. P0302 - Cylinder 2 Misfire
2. P0410 - Secondary Air injection
3. P0340 - Camshaft sensor A (sometimes)
4. P0600 - Serial communication Link
5. P0720 - Output speed sensor (sometimes)

other problem that I faced is that I can't switch S and W mode (is it related?).

I hope you guys can help me out before I'm losing $$$ for something useless. Please help me brother and sister. I really appreciate any help you can provide.

 

[4life211]

What is the problem you have ? Your car feels jerky or smth else .What are the symptoms you have?

 

[Usheruff]

Engine vibration because I'm running with 3 cylinder instead of 4. Vibrated when idle

 

[exvolvoman]

Tried new plugs??
S & W mode shouldn't be related as this is for the gearbox, this may be a stuck switch, it was on mine, squirt of switch cleaner cured it.

 

[grober]

https://mbworld.org/forums/c-class-w203/350286-m111-ignition-coils.html

I'm guessing your coils are like this. If so its a lost spark system where two plugs fire at once. 1+4 or 2+3 If you have 4 coils ignore what follows . each coil has an extender under it that sits on their respective spark plug. sometimes moisture gets in or they crack causing a misfire. Take a look at the plugs when you take them out and shine a torch down the empty plughole to look at the top of the piston- if it looks oily/wet you may have a head gasket problem. Other possibility is one of the [2] ECU power transistors has gone down.

 

[Usheruff]

Already changed new plugs for all cylinder.

 

[Usheruff]

https://mbworld.org/forums/c-class-w203/350286-m111-ignition-coils.html

I'm guessing your coils are like this. If so its a lost spark system where two plugs fire at once. 1+4 or 2+3 If you have 4 coils ignore what follows . each coil has an extender under it that sits on their respective spark plug. sometimes moisture gets in or they crack causing a misfire. Take a look at the plugs when you take them out and shine a torch down the empty plughole to look at the top of the piston- if it looks oily/wet you may have a head gasket problem. Other possibility is one of the [2] ECU power transistors has gone down.

Mine look like this(4 coils). Could you please provide me more information regarding ECU power transistor and how to solve it? Thanks for your prompt reply and help.

 

[LvR]

General observation.........

1. swap ignition coils.
2. swap fuel injectors.

didn’t solve the issue ..............

OK - that tells you its either a (mechanical) compression issue or you have an electrical issue confined to cylinder 2 related to either fuel or spark.


Simple and easiest test first I would suggest - do an all 4 cylinder comparative compression test .................... cylinder 2 a lot different than the others?

If that’s not the cause you have way more serious issues:

P0600 - Serial communication Link

This alone could also be responsible but the presence of

2. P0410 - Secondary Air injection
3. P0340 - Camshaft sensor A (sometimes)

makes me suspect you have electrical issues related to the ECU.

If the compression test doesn’t explain it, its will be time to inspect ECU connections and harness integrity.

Your codes you report - are they off a STAR scanner session? ................... STAR will tell you exactly what to go look for

 

[grober]

Sadly there is no information regarding Mercedes ECU circuitry in the official MB literature. They are usually portrayed as a black box. In terms of what happens the operating principle for each ignition coil is that its coil is supplied with 12v and its fired by switching the coil to earth via a power transistor in the ECU. If any of the switching transistors has failed it means sending the ECU off for repair to a repair specilaist or swapping it for a good second hand one.
However having read your post again where you detail numerous intermittant electrical faults LvR's advice to inspect the wiring loom is a good one. In addition to physical loom damage some of these cars have a problem with oil migration up the wiring loom till it reaches the ECU! So an inspection of the ECU loom connection is a must!
See this thread:- https://mbworld.org/forums/c-class-w203/237667-m111-leaky-cam-sensor-replacement.html

 

[Usheruff]

Hi LvR and Grober,

Thanks for the information given. You guys are awesome. Btw, I checked my Code report via OBD Car doctor and Torque apps. Both apps shows same codes. I'll bring my car for compression test first and see the result. I hope there's no major problem...

 

[LvR]

That LTFT ..............reason for it being that low? (should ideally be closer to 0)
STFT on 0 .............. incredible coincidence?
ECT reported there - because the engine was still cold?