CLS 63 2011 Misfire M157

[sambam2006]

Hi guys,

I purchased a CLS 63 2011 on 7th September privately and on the 13th the car began to misfire on the M1 motorway and the engine light came on, the car was hesitating on idle and juddering. At some occasions the engine management light was flashing.

Managed to get it to a local specialist who I know and they plugged it in and got the following codes:

P0306 - Cylinder 6 Misfire
P0307 - Cylinder 7 Misfire

They cleared the codes and the ones above kept coming back. So far I have taken it to 2 garages (Mercedes Specialists) but they have been unable to source the problem. None of the garages have worked on the M157 garages I have spoken to .

First Garage: Changed 4 Coil Packs and 4 Spark Plugs = Same misfire problem and same codes.

Second Garage: Currently Diagnosing it

Any advice you guys can give? (Car is out of warranty)

A detailed video can be seen below:

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[daveenty]

It needs proper Mercedes diagnostics using a STAR machine and, more importantly, an operator who knows how to use it. Anything else is second guessing as you're starting to find out.

If you let us know your location then people may be able to recommend a person in your area who will be familiar with these engines.

Is the car modified at all, specifically the exhaust system?

 

[Abb]

Perhaps give Acid a call at MSL??

 

[bluestreak]

hopefully it is just spark plugs in affected cylinders.

generally one of four things:

- spark plug
- ignition coil
- injector
- compression

usually the first two depending on service history and mileage

 

[sambam2006]

It needs proper Mercedes diagnostics using a STAR machine and, more importantly, an operator who knows how to use it. Anything else is second guessing as you're starting to find out.

If you let us know your location then people may be able to recommend a person in your area who will be familiar with these engines.

Is the car modified at all, specifically the exhaust system?

I have two diagnostic readers of my own and it's been connected to Autologic and Mercedes Star which didn't give much information apart from the same, Cylinder Misfire 6 and 7.

If I tried to drive the car then 5 and 8 would also start to misfire alongside 6 and 7

The car has been remapped by previous owner, tuners were AMD Tuning.
And exhaust has had a mod by previous owner

Perhaps give Acid a call at MSL??

I have been in contact with Adnan from MSL in Bradford, he told me to get a compression test done but none of the garages I have been too have been able to do it. (I'm currently at my 2nd Mercedes Specialist lol). These guys dont use star but only Autologic.

hopefully it is just spark plugs in affected cylinders.

generally one of four things:

- spark plug
- ignition coil
- injector
- compression

usually the first two depending on service history and mileage

The first garage I went to replaced ignition coil and spark plugs

I am waiting for my injectors to arrive from Germany

No compression test done yet

 

[bluestreak]

star should be able to update ECU to rule out incorrect mapping. Multiple misfires are quite dramatic and it is quite unlikely to have multiple injectors fail the same time. compression test should be a priority.

I've seen videos of cylinder block damaged by power race. Really hope that isn't the case here.

 

[alecmascot]

There is thread here
http://tinyurl.com/y8nny2uo
about plug gaps being critical in tuned M157 engine.

 

[sambam2006]

star should be able to update ECU to rule out incorrect mapping. Multiple misfires are quite dramatic and it is quite unlikely to have multiple injectors fail the same time. compression test should be a priority.

I've seen videos of cylinder block damaged by power race. Really hope that isn't the case here.

The garage managed to use a Mercedes star today and found irregularities in Cylinder 6, they didn't really give me much more information than that. But I have already ordered injectors which should arrive tomorrow afternoon so time will tell, fingers crossed it's the injectors only. I told them to update ECU back to Mercedes one but they using aliexpress Xentry lol.

There is thread here
http://tinyurl.com/y8nny2uo
about plug gaps being critical in tuned M157 engine.

Thank you for the link, interesting read there didn't realize this would even cause an issue, will keep this in mind

 

[sambam2006]

UPDATE: It was difficult finding a Mercedes Specialist that had Star Diagnosis (Online), but finally took it to AutoClass in Milton Keynes and they tried to update the ECU but it already had the latest software so they did SCN coding to it and reset all values.

Problem solved, no more misfire or CEL, car is running like nothing happened.