BMW 318i 2009 E90 smells like burnt oil and smokes?

Question

I have the following problem:

My girlfriend's BMW ran on 3 cylinders. After the diagnosis, the ignition coil on cylinder 1 was replaced. She drove around in the car for 3 weeks. ‍

It is actually running perfectly now, but there is a lot of smoke and it smells of burnt oil.

In the cold state everything is OK, but not so as soon as it is warm, especially when starting up and at partial load. No smoke is noticeable under full load.

It's been in the garage for a few months now, so now I'd like to take the time to solve the problem. I suspect that the catalytic converter was damaged by driving on 3 cylinders or is dirty with oil and gasoline. Is that plausible or rather improbable? I discovered a trace of oil on the valve cover seal, could it be because of that? P101b is also stored in the error memory. According to Google, this is probably due to the "Valvetronic", but it can also be because I had to bypass it.

Vehicle data:

BMW 318i E90

Year of construction 2006

Engine code N43.

Answer 1

If it smokes and smells, that's a sure sign of oil burning. I lean far out of the window and claim that the replacement of the ignition coil for cylinder was completely unnecessary. A new candle would have done it too. When the oil burns, it is only a matter of time before the cylinder fails again because of a sooty candle or even a carbon thread between the electrodes.

It either pulls oil past the piston and piston rings into the combustion chamber or past the valve stem seals.

In any case, it won't cost more than a few minutes and dollars to repair.

Traces of oil on the valve cover seal are only noticeable as smoke if oil runs on very hot engine parts. Manifold, flame tube... In any case, it has nothing to do with black smoke from the exhaust.

Answer 2

If she's lucky, it'll just burn the mess out of the exhaust system and it'll stop soon. If she's unlucky, there is something damaged by it - from driving on three cylinders.

Check oil consumption.