[ConorG-McC]

Hi all,

Looking for some advice on this issue.

Year: 2011
Model: 118i
Engine: N13
Mileage: 100,100

Car hit 100,000 miles this week and received periodic misfires but would go away on a restart etc. With it being at 100k i decided to replace all of the spark plugs and coils at the same time to have a clean slate.

During the change i noticed a lot oil on the end of two of the ignition coils which i suspected was a carry over from the rocker cover gasket symptoms. I got this gasket replaced September with my local mechanic at the same time as having my alternator belt replaced.

After replacing with the 4 bosche iridium spark plugs and the Deplhi ignition coils, the engine starts and appears to be fine.
Once i drive it from my driveway to the end of the street, on acceleration out of the street the car throws the DRIVETRAIN MALFUNCTION and begins to shake roughly until turned off on return to my home.

When returning to the car with daylight this morning, I removed all of the spark plugs and coils and turned the engine for 2-3 seconds a few times incase there was any oil residue that i had missed when clearing it previously (advice from online). This had no luck and experienced the EXACT same scenario when attempting to drive.

Any advice/guidance on what to do next or things to check?

[sailorbob]

Drivetrain error is caused by many things so the best thing to do is get a OBD-II diagnosis done to determine the error(s) the ECU has stored so you know what to investigate further.

[ConorG-McC]

I have a Veepeak OBD-2 and used that. The codes that i am getting are:

P0304 - Cylinder 4 misfire detected
140010 - Misfire in several cylinders detected
140410 - Combustion misfire cylinder 4
140001 - Misfire several cylinders: injection is cut out
140401 - Misfire cylinder 4: injection is cut out

[sailorbob]

I would look at the following in this order:

Sparking plugs - I believe the OE plugs are Beru so I'd try them.
Coils - On the N55 engine Delphi coils can be hit and miss depending on where they are made so it may be the same for your engine. There are rubbish knock offs out there too so trying a genuine coil in cylinder #4 would be worthwhile.
Injectors - Swapping injectors over but you'll need new injector seals and I'm guessing the injectors are probably coded to each cylinder so that'll need doing too.

[ConorG-McC]

Originally Posted by ConorG-McC

After replacing with the 4 bosche iridium spark plugs and the Deplhi ignition coils, the engine starts and appears to be fine.
Once i drive it from my driveway to the end of the street, on acceleration out of the street the car throws the DRIVETRAIN MALFUNCTION and begins to shake roughly until turned off on return to my home.

This morning i had a local mechanic nosey and scan the car himself for a bit of advice on potential issues. He had a suspicion that one of the spark plugs has been bad and to return the best of the old spark plugs to cylinder 4 and see.

Right enough, the car ran like new after taking out the 'new' plug in cylinder 4. The other 3 plugs bought at the same time are fine.

Going to return back to where this was purchased, inform them, swap this for another. Going to change it in the car park of the place to ensure it isnt part of the same bad batch etc.

As he said, 'every day is a school day'

[sailorbob]

Probably the cheapest repair so a great result