[raffi007]

Hello guys
I need your help trying to analyze what is happening with me N54 335xi

So a couple months back my crankcase dies because of a spun bearing, so i had to rebuild the full engine.
I didn’t know the reason why the crankcase bearing spun.
So fast forward a couple of weeks after the engine was rebuilt.
The car runs smooth, no problems with the engine.
But one morning as i turn on the engine and went behind the car i saw a puff of white smoke which disappeared quickly and then nothing. I monitored the car by placing a gopro on the back bumper and no white smoke while driving.

But i wanted to find out why there was a white smoke in the mornings.
So i started researching a bit and came to understand that it could be a leaking injector. Which also explains the crankcase problem if fuel go into the oil and thinned it down.

So i removed the sparkplugs of each cylinder and inserted a camera into the cylinders and saw that :
1- spark plug 1 had a black/wet-ish look
2- the cylinder head 1 also was a bit wet/black compared to all the rest of the 5 cylinders.

So i concluded that injector 1 was leaking, and since all my injectors were index 11, i replaced the injector 1 with a used index 12 and coded it.

To my surprise the white puff in the morning didn’t stop but after a week i pulled all the spark plugs again and inserted the camera and things looked like they were back to normal

Fast forward another week, out of curiosity i pulled the plugs again and saw that the black/wet problem is back

After inspecting the spark plug 1 and comparing it with the rest i saw that the gap between the 3 heads and the center pin were way bigger than the rest of the plugs, so i concluded that maybe thats the problem since the mixture fuel/air isn’t being burnt correctly since the spark generated is not strong.

I took some pliers and pushed the pins to the correct distance and went ahead and ordered a full set of 6 delphi coils and 6 spark plugs.

By watching the videos, can you understand what is exactly the reason for this problem ?

[Cm452]

This gonna be offensive to a few of you, but have a friend start the car while you stand by the exhaust. Once the smoke emerges, gently waft the surrounding air towards you; don't huff the fumes or smoke though. You'll easily be able to discern between oil, fuel, or coolant. You could also have worn valve guides, which admit a little bit of oil after the engine cools and sits. Also, sniff the residue on the spark plugs and rub it between your fingers--whatever it is will again be easy to identify. If you've never smelled coolant it smells kinda like how artificial sweeteners taste. Unburned fuel smells like raw gas, and oil will smell like 2-stroke or like a Honda with a fart cannon spewing blue clouds.
Fill us in with your findings.
-Cm

[raffi007]

Originally Posted by Cm452

This gonna be offensive to a few of you, but have a friend start the car while you stand by the exhaust. Once the smoke emerges, gently waft the surrounding air towards you; don't huff the fumes or smoke though. You'll easily be able to discern between oil, fuel, or coolant. You could also have worn valve guides, which admit a little bit of oil after the engine cools and sits. Also, sniff the residue on the spark plugs and rub it between your fingers--whatever it is will again be easy to identify. If you've never smelled coolant it smells kinda like how artificial sweeteners taste. Unburned fuel smells like raw gas, and oil will smell like 2-stroke or like a Honda with a fart cannon spewing blue clouds.
Fill us in with your findings.
-Cm

Honestly i smelled the smoke and i cannot tell you precisely what the smell is.
It doesn’t smell like gas or coolant but it should technically smell like oil but my impression wasn’t clear that it was oil.
Very weird

[dpaul]

Originally Posted by raffi007

Hello guys

So i concluded that injector 1 was leaking, and since all my injectors were index 11, i replaced the injector 1 with a used index 12 and coded it.

To my surprise the white puff in the morning didn’t stop but after a week i pulled all the spark plugs again and inserted the camera and things looked like they were back to normal

Fast forward another week, out of curiosity i pulled the plugs again and saw that the black/wet problem is back

After inspecting the spark plug 1 and comparing it with the rest i saw that the gap between the 3 heads and the center pin were way bigger than the rest of the plugs, so i concluded that maybe thats the problem since the mixture fuel/air isn’t being burnt correctly since the spark generated is not strong.

I took some pliers and pushed the pins to the correct distance and went ahead and ordered a full set of 6 delphi coils and 6 spark plugs.

If plug #1 is black/wet and smells like gas, the injector is leaking. There is not another simple explanation for this. And after all, you purchased a used injector so you don't know its history.

In testing for leaking in the situation you describe, it is important that you pull the plug in the morning after the engine has sat all night and is cold, not on a hot engine after running.

If the mis-gapped plug resulted in a weak spark and poor/intermittent ignition, you'd get a misfire code.

Since you are able to code the injectors yourself, you could always swap cylinder #1 injector to a different cylinder - if the black/wet follows, then your "new" used injector is leaking.

It is worth thinking about why the gap on plug #1 is larger than normal - if this is something that very recently occurred it could be the result of detonation/preignition, foreign material in the combustion chamber or even partial hydrolock from too much fuel. It's pretty unusual for the plugs to be grossly misgapped from the factory and not likely that plug #1 was so much older than the others that the gap was the result of natural wear. Can you say with any confidence when the large gap appeared?

Finally, relevant to the issue of odor - I've experienced the white smoke on startup resulting from badly leaking injectors and personally could not identify any characteristic odor in the exhaust. But the black/wet plugs that smelled like fuel were obvious.

[raffi007]

Originally Posted by dpaul

If plug #1 is black/wet and smells like gas, the injector is leaking. There is not another simple explanation for this. And after all, you purchased a used injector so you don't know its history.

In testing for leaking in the situation you describe, it is important that you pull the plug in the morning after the engine has sat all night and is cold, not on a hot engine after running.

If the mis-gapped plug resulted in a weak spark and poor/intermittent ignition, you'd get a misfire code.

Since you are able to code the injectors yourself, you could always swap cylinder #1 injector to a different cylinder - if the black/wet follows, then your "new" used injector is leaking.

It is worth thinking about why the gap on plug #1 is larger than normal - if this is something that very recently occurred it could be the result of detonation/preignition, foreign material in the combustion chamber or even partial hydrolock from too much fuel. It's pretty unusual for the plugs to be grossly misgapped from the factory and not likely that plug #1 was so much older than the others that the gap was the result of natural wear. Can you say with any confidence when the large gap appeared?

Finally, relevant to the issue of odor - I've experienced the white smoke on startup resulting from badly leaking injectors and personally could not identify any characteristic odor in the exhaust. But the black/wet plugs that smelled like fuel were obvious.

You raise a very interesting point concerning the gap on plug 1 : all my plugs were replaced 10.000KM ago, before the engine was rebuilt.
I already have 1200km on the new engine after the rebuild so basically the new plugs were installed 9000kms before that.
I also found it weird that it is such a coincidence that i have a gap on plug 1 and at the same time the piston head is wet/black.
Maybe the scenario you said actually happened. Injector 1 was leaking which resulted in a partial hydrolock due to too much fuel in the cylinder, which also was the reason fuel go its way into the oil which resulted in the the bearing of the crankcase to turn.

I just replaced plug 1 with a brand new one today while waiting to receive the full set of 6 coils & plugs from FCPEuro next week.

I just took another video 10min ago which shows that the piston is kind of dry compared to before.
I will check it again tomorrow morning and report back.

This video shows the new plug after a 25km drive

[dpaul]

It is hard for me to tell with the videos but when you describe the plug as black/wet are you talking about the threaded region or the tip? In most of the videos, the tip does not appear black or wet.

Black/wet on the threaded region is from oil leaking from the valve cover or valve cover gasket into the spark plug well.

Black/wet at the tip would most likely be from a leaking injector.

Again, the most reliable way to inspect for leaking injector is to pull ALL THE PLUGS in the morning BEFORE starting the engine. Your smoke puff on startup could very well be from a leaky injector but it does not have to be #1 cylinder

[raffi007]

Originally Posted by dpaul

It is hard for me to tell with the videos but when you describe the plug as black/wet are you talking about the threaded region or the tip? In most of the videos, the tip does not appear black or wet.

Black/wet on the threaded region is from oil leaking from the valve cover or valve cover gasket into the spark plug well.

Black/wet at the tip would most likely be from a leaking injector.

Again, the most reliable way to inspect for leaking injector is to pull ALL THE PLUGS in the morning BEFORE starting the engine. Your smoke puff on startup could very well be from a leaky injector but it does not have to be #1 cylinder

What i will do is pull all the plugs tonight and take a video, and will do the same tomorrow morning before starting the car and will post the 2 videos.

I am suspecting cylinder 1 because it is the only one that shows black and wet symptoms on the piston head the rest are dry and clean

[raffi007]

So here is the video of all plugs and piston head which i filmed tonight at midnight. (Last time the car was driven was at 9pm)

Tomorrow at noon i will film all of it again to check if any fuel or oil has leaked inside the piston heads overnight.

[raffi007]

So here it is
The plugs stayed off the car for 12 hours.
The car stayed parked for 12 hours
The piston head seem dry/clean yet the white smoke persists on cold start in the morning

[gster109]

Did you ever figure this out???