[///Mposter]

So you have an MHD tune? Make sure exhaust burble is off . It can cause that issue by expelling too much gas and the CCs can't convert it fast enough.

To be on the safe side of diagnosis, you can eliminate at least 3 cylinders by pulling the d o w n p I p e s off and looking at the turbine compressor wheels. If an oil deal is busted , you will see oil. If you have a coolant leak you will see the area white. If you see an extreme black soot looking area , you might be running too rich of a fuel table / or leaky injector on that bank. Normal would be just a cast iron brown look.
Only by taking the whole turbo off would you be able to see the second step which could be a leaky valve stems. That would be an oil issue leaking past the stem. ( most likely not your issue)

Once you can eliminate some of those , you will know where to focus. There is a good video showing how to test for a leaky injector, or you could log and see which cylinder value is off.

You could also have a PCV issue, as some do tend to get gummed up and stuck.
Also want to reiterate about blown turbo seals. Usually it's the rear because the drain clogs. After removing my turbos I know why. It seems as if the rear drain sits lower on the pan relative to the front . I was able to remove the front turbo with nothin leaking out of the pan, while after removing the rear drain, oil came rushing out. Make sure you do not overfill the oil when doing an oil change. And make sure after running a hard run you allow oil circulation so that hot oil doesn't sit in the drain line and cake up. You don't have to worry much about turbo timers for coolant but the oil just sits there while water pump runs when the car is off.

Best of luck on troubleshooting this smoking issue. It only will get worse with the straight pipes.

[RGP-N54]

Originally Posted by ///Mposter

So you have an MHD tune? Make sure exhaust burble is off . It can cause that issue by expelling too much gas and the CCs can't convert it fast enough.

To be on the safe side of diagnosis, you can eliminate at least 3 cylinders by pulling the d o w n p I p e s off and looking at the turbine compressor wheels. If an oil deal is busted , you will see oil. If you have a coolant leak you will see the area white. If you see an extreme black soot looking area , you might be running too rich of a fuel table / or leaky injector on that bank. Normal would be just a cast iron brown look.
Only by taking the whole turbo off would you be able to see the second step which could be a leaky valve stems. That would be an oil issue leaking past the stem. ( most likely not your issue)

Once you can eliminate some of those , you will know where to focus. There is a good video showing how to test for a leaky injector, or you could log and see which cylinder value is off.

You could also have a PCV issue, as some do tend to get gummed up and stuck.
Also want to reiterate about blown turbo seals. Usually it's the rear because the drain clogs. After removing my turbos I know why. It seems as if the rear drain sits lower on the pan relative to the front . I was able to remove the front turbo with nothin leaking out of the pan, while after removing the rear drain, oil came rushing out. Make sure you do not overfill the oil when doing an oil change. And make sure after running a hard run you allow oil circulation so that hot oil doesn't sit in the drain line and cake up. You don't have to worry much about turbo timers for coolant but the oil just sits there while water pump runs when the car is off.

Best of luck on troubleshooting this smoking issue. It only will get worse with the straight pipes.

Writing this again.. E90post bugged out
I replaced my coolant this morning. I flashed my car back to Stage 1 without the aggresive burble mod and then took the car for a ride. Had my camera and nostrils wide open prepped for the worst. But nothing, I took the car down a straight and did multiple stop and go's since that's usually when it occurred. I guess as of now the problem is solved, will update if the smoke returns. Thanks everyone for the help! Planning on doing a secondary cat delete soon to accompany my VRSF.. er, Tubes that come down.
(Still not sure why *that* word is banned.)

TLDR; MHD Aggresive burble is the culprit.. for now

[dannyjones]

Originally Posted by STR8-6IX

BMW's are known to consume coolant so low coolant isnt going to tell you much. you can open the reservoir when the engine is hot, its actually good for the system its just going to release pressure. however, you only get an accurate coolant reading when the vehicle is cold

What!?!? They should not consume coolant and opening the reservoir when up to temperature will result in coolant overflowing everywhere at high temperature (>100C) and you'll probably seriously burn yourself.

[Gohan335i7]

Maybe your Vanos Solenoids need replacing. When mine went bad, white thick smoke came out of my exhaust,& my car was stumbling right when it turned on. Best of luck.

[RGP-N54]

Originally Posted by ///Mposter

So you have an MHD tune? Make sure exhaust burble is off . It can cause that issue by expelling too much gas and the CCs can't convert it fast enough.

To be on the safe side of diagnosis, you can eliminate at least 3 cylinders by pulling the d o w n p I p e s off and looking at the turbine compressor wheels. If an oil deal is busted , you will see oil. If you have a coolant leak you will see the area white. If you see an extreme black soot looking area , you might be running too rich of a fuel table / or leaky injector on that bank. Normal would be just a cast iron brown look.
Only by taking the whole turbo off would you be able to see the second step which could be a leaky valve stems. That would be an oil issue leaking past the stem. ( most likely not your issue)

Once you can eliminate some of those , you will know where to focus. There is a good video showing how to test for a leaky injector, or you could log and see which cylinder value is off.

You could also have a PCV issue, as some do tend to get gummed up and stuck.
Also want to reiterate about blown turbo seals. Usually it's the rear because the drain clogs. After removing my turbos I know why. It seems as if the rear drain sits lower on the pan relative to the front . I was able to remove the front turbo with nothin leaking out of the pan, while after removing the rear drain, oil came rushing out. Make sure you do not overfill the oil when doing an oil change. And make sure after running a hard run you allow oil circulation so that hot oil doesn't sit in the drain line and cake up. You don't have to worry much about turbo timers for coolant but the oil just sits there while water pump runs when the car is off.

Best of luck on troubleshooting this smoking issue. It only will get worse with the straight pipes.

Originally Posted by Gohan335i7

Maybe your Vanos Solenoids need replacing. When mine went bad, white thick smoke came out of my exhaust,& my car was stumbling right when it turned on. Best of luck.

Posted resolution above haha. Thanks for the help man, it could be my vanos solenoids acting up soon but so far car is running fine.. will keep everything in note. Poor turbo seals and vanos solenoids seem to be the two most logical ones in my situation, once again thanks everyone for the help!

[galahad05]

Yeah, a good takeaway from this is: white smoke on startup COULD be water/coolant, but it could also be excess fuel going unburned through the exhaust. Thus vanos solenoids, ecu programming for exhaust overrun noise (burble) or leaking injectors. It hadn't occurred to me before about our n54s, but the fuel system is one of the less reliable parts of our cars.

[RGP-N54]

Originally Posted by galahad05

Yeah, a good takeaway from this is: white smoke on startup COULD be water/coolant, but it could also be excess fuel going unburned through the exhaust. Thus vanos solenoids, ecu programming for exhaust overrun noise (burble) or leaking injectors. It hadn't occurred to me before about our n54s, but the fuel system is one of the less reliable parts of our cars.

Bingo
TLDR For whole thread - your problem can be one of the four;
1. Head gasket
2. Vanos solenoids
3. Excess burble in tunes - in my case MHD
4. Leaking injectors

[NW 335i]

Originally Posted by STR8-6IX

BMW's are known to consume coolant so low coolant isnt going to tell you much. you can open the reservoir when the engine is hot, its actually good for the system its just going to release pressure. however, you only get an accurate coolant reading when the vehicle is cold.

what mileage are you at again? I suspect your car is just burning alot of oil and is in rough shape because metal pistons expand when hot, filling the cylinders and thus slowing down oil consumption. you would need an engine rebuild (new piston rings and probably valve stems, then very carefully break it in with 3000 miles of city driving, no more then 3000rpm)

but I doubt this is worth it. if the rest of the car is in good shape and worth keeping, you might want to consider swapping a new motor in but check to make sure it cant be fixed first.

Holy shit! LMFAO!

[AZDAVEBROWN]

This may or not apply since I have a N52. Had the exact same issue. Pulled both my vanos solenoids, cleaned them and switched (intake to exhaust and exhaust to intake). That was 8000 miles ago. No problem since.

[Wolf 335]

Originally Posted by galahad05

Yeah, a good takeaway from this is: white smoke on startup COULD be water/coolant, but it could also be excess fuel going unburned through the exhaust. Thus vanos solenoids, ecu programming for exhaust overrun noise (burble) or leaking injectors. It hadn't occurred to me before about our n54s, but the fuel system is one of the less reliable parts of our cars.

If an injector is leaking to the point of that much smoke building up, your car will definitely throw a code and go into limp mode. You will also definitely smell gasoline in the exhaust pipe.

Usually slight misfires at idle are compensated by ecu with increased rpm.

[galahad05]

Originally Posted by Wolf 335

If an injector is leaking to the point of that much smoke building up, your car will definitely throw a code and go into limp mode. You will also definitely smell gasoline in the exhaust pipe.

Usually slight misfires at idle are compensated by ecu with increased rpm.

Yeah, that's what happened in my case. Misfires and codes thrown. I had something like index 1 injectors that started dying around 40k miles.