.BMW N54 smoking. Input and feedback needed.

Sixbanger

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Jun 20, 2017
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I've owned my car since 2008 and I'm lost as to what to do next with my current issue. I've maintained this car very well since day one and have continued to all this time. Car has currently 150,000 miles on the odometer.
1. Re-manufactured turbos installed 5/2019
2. Valve cover replaced with a new oem cover and oem pcv valve 8/2021
3. new plugs (NGK) and coils done back in 2019) which plugs not sure.
4. compression test done this year see attached pic on numbers
5. currently running a custom tune (lowered power back in July) my tuner retired and I havent done a log in a while. Not sure if that would produce smoking.
current mods:
VRSF charge pipe and tial bov
vrsf catless downpipes and first set of resonators were removed a few years ago
afe cold air intake
fuel it ethanol sensor (havent used it since running E85 2+ years ago) running 93 pump
BMS catch can that doesnt catch oil lol

Heres what happened. Last night I was leaving a restaurant and when I was driving slow to pull out of the parking lot I got a big puff of smoke. That hasn't happened since I replaced my valve cover recently. I was confident the issue was resolved back when I replaced my valve cover a few months ago. This past 2 weeks I did drill into my intake manifold to install a 1/4 inch adapter so the bov can flow better. Last week I used STP valve cleaner to clean the valves and poured liqui moly valve cleaner into the closed valves and scrubbed. It only smoked last weekend on the day I cleaned the valves then it stopped. I understand its normal for the N54 to smoke, but what else could be the culprit? Turbos? valve seals? should I have a mechanic look at it?
 

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RuskiRacer

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Jul 17, 2019
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I've seen injectors seals blow out and dissappear and contribute to a low compression reading make sure all your injector seals are in tact
 
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corbanistan

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Jul 26, 2021
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^ Good point Rusdki. I'd go thru everything, make sure everything is on correctly and buttoned up. Then recheck compression. Hope it isn't valve stem seals as I haven't heard of that being much of an issue with our N54. Check PCV stuff too
 

Sixbanger

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With everything you've all said I'm going to take a visit to my local mechanic and have him check everything. I'll follow up in a week with an update. Thank you all.
 
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Sixbanger

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FYI that compression test was a dry one. I didn't mention it in my original post.
 

Sixbanger

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a little update. I pulled the plugs and coils today. The last time I replaced my coils was over 4 years ago (fcp euro). The sparkplugs were replaced back in August of 2019. Today as I was pulling out the coils cylinder one coil broke off in half. I replaced the valve cover and gasket in July of this year. Yesterday I went to the auto store to pick up some oil because the level went down a little. I dumped in a quart but I spilled a little oil and it dropped down. Also notice Im leaking from the oil cap, what do I need to repair the oil leak from the cap?
After the oil spill was noticed today I sprayed brake cleaner cautiously around plug 4 and thats why it looks bad. I dont know what to take from all of what I did today. I did order new plugs and coils and they should be here soon. I'm still going to take the car to my mechanic later this week and have him evaluate the injectors and re-do compression test.
 

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SlowE93

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Jul 2, 2017
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a little update. I pulled the plugs and coils today. The last time I replaced my coils was over 4 years ago (fcp euro). The sparkplugs were replaced back in August of 2019. Today as I was pulling out the coils cylinder one coil broke off in half. I replaced the valve cover and gasket in July of this year. Yesterday I went to the auto store to pick up some oil because the level went down a little. I dumped in a quart but I spilled a little oil and it dropped down. Also notice Im leaking from the oil cap, what do I need to repair the oil leak from the cap?
After the oil spill was noticed today I sprayed brake cleaner cautiously around plug 4 and thats why it looks bad. I dont know what to take from all of what I did today. I did order new plugs and coils and they should be here soon. I'm still going to take the car to my mechanic later this week and have him evaluate the injectors and re-do compression test.
Maybe I need to go over the whole thread again....but why mismatched spark plug ?
 

Sixbanger

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Maybe I need to go over the whole thread again....but why mismatched spark plug ?
My mechanic threw that in there when he did the compression test earlier this year. When he did the compression test he broke the plug. I specifically asked him why not just get another NGK. He said nothing bad will happen and I'll be fine and he couldnt get the NGK plug from his sources. What can I do? I took his word.
 

Sixbanger

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I've seen injectors seals blow out and dissappear and contribute to a low compression reading make sure all your injector seals are in tact
vrsf catless down pipes
first set of resonators removed
afe intake
csf radiator
vrsf front intercooler
stock turbos that were rebuilt and balanced in 2019 with bigger turbine wheel
custom tune boost lowered ever since low compression results
Eisenmann axle back exhaust
 

corbanistan

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Jul 26, 2021
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If you're leaking from the oil cap you could have too much crankcase pressure building up, I'd service the PCV system. I've seen PCV issues cause smoke on M3s. You already did valve cover, so that's one thing out of the way. You should think about replacing the valve near the back of the cover with an upgraded metal one that you can get from various sources. Got mine from FCP for lifetime warranty.
 
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Sixbanger

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Jun 20, 2017
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If you're leaking from the oil cap you could have too much crankcase pressure building up, I'd service the PCV system. I've seen PCV issues cause smoke on M3s. You already did valve cover, so that's one thing out of the way. You should think about replacing the valve near the back of the cover with an upgraded metal one that you can get from various sources. Got mine from FCP for lifetime warranty.
When I replaced teh valave cover on my car the new one came with the plastic one. So, get the metal one from VTT?