W203 C180K coupe misfire on cylinder 1 help!

[craigw131]

Hi all, been having a few issues with my C180K coupe misfiring. When read it comes up with code P301 Cylinder 1 misfire detected. It only starts misfiring when accelerating quickly and puts the EML on. It also starts to shake and loses power. It seems to be ok upto around 4000rpm and drives great with plenty of power and smooth acceleration

In order to rectify this I have so far done the following:
Replaced the valve cover gaskets including the spark plug cover gaskets and the oil filler cap seal. This was due to finding a pool of oil in my spark plugs 1 and 2. Also replaced all 4 spark plugs and topped up with oil. Also have swapped the coil packs to see if the problem moves. It is always cylinder 1 that has the problem so I think I can eliminate the coil pack as the issue.
I have removed and cleaned the MAF using proper maf cleaning spray.

I have noticed today that the breather pipe from the airbox into the top of the engine has gone really soft and has a couple of small holes so will be replacing that as soon as I can get one ordered.
I have also tested the resistance of the fuel injectors and they all settle at 12.2. I assume this means that the injectors are all functioning properly

Can anyone think what the problem might be, as I am really starting to run out of ideas to fix it.

Any ideas gratefully received.

 

[mattkh]

Check and clean the connector to the number 1 coilpack.

 

[LostKiwi]

Have No1 injector checked.

 

[craigw131]

Have already checked the resistance on all injectors and they all are the same. Could there still be a problem with injector no1, like maybe it is stuck open? I only ask because sometimes there is a strong smell of petrol from the exhaust

 

[LostKiwi]

Have already checked the resistance on all injectors and they all are the same. Could there still be a problem with injector no1, like maybe it is stuck open? I only ask because sometimes there is a strong smell of petrol from the exhaust

Yes there could. If it doesn't open properly or close properly or the spray pattern is bad it can cause issues.

 

[craigw131]

Just to update, have now removed, checked and cleaned all injectors, replaced the breather pipe. Still have the exact same problem. Under acceleration EML comes on and when read comes up with P0301 cylinder 1 misfire detected.

Anything else it could be? I have checked the wiring to the coil packs and sprayed them with electrical contact cleaner. I am seriously at a loss what to do next.

 

[AMGeed]

Hope it isn't connected, but have you read about the inherent M271 engine problems with the timing chain and cam sprockets?

 

[Arv]

Just to update, have now removed, checked and cleaned all injectors, replaced the breather pipe. Still have the exact same problem. Under acceleration EML comes on and when read comes up with P0301 cylinder 1 misfire detected.

Anything else it could be? I have checked the wiring to the coil packs and sprayed them with electrical contact cleaner. I am seriously at a loss what to do next.

Perhaps injector cyl 1 is leaky even after cleaning? Please do watch this video,
may help. If your injector is leaking even after cleaning, you will see it sputtering
during testing.

How to test the Fuel Injectors for Leaks / Pressure Drop / Multimiter Test DIY

-----------
How to Check For Leaking Fuel Injector and Fixes - Rx Mechanic

| Rx Mechanic

Read on to learn how to check for leaking fuel injectors to ensure your engine runs optimally and prevent fire outbreaks from external injector leaks and vacuum leaks.

rxmechanic.com

 

[Cole@MBS]

That engine back in the day was prone for carbon build up and sticking valves! Used to be a program on star to burn the carbon out! Not seen one for a while now!

 

[craigw131]

What is really annoying is that the car is really nice to drive and pulls well. As soon as you accelerate hard though that's when it puts the EML on and starts shaking. If I manage to keep it under 4000 rpm its drives perfectly. Its always cylinder 1 that has the fault according to my code reader

 

[mioba]

Sounds like a shot injector.