Car smoking ocasionally

[daimlerush]

Hi,
I have an bmw x1 xdrive 2.0 e84 
Some time ago I was driving in town centre and noticed alot of smoke coming out from tailpipe especially when accelerating.  The smoke's colour was white/grey and smells like burn oil. I also had the oil light on after some time. I called the nearest garage I could find at that time and left the car there for the mechanic to have a look. From what he said he tested turbo, he did a comparison test, and flushed the engine 3 times. (That's what I was told and charged £500).
In the meantime car has the same problem, is smoking ocasionally and every episode lasts aprox 2-5 mins. I noticed today after driving it for aprox 30mins  that if I stop the engine and turn it back on the smoking stops for some reason. 

Things that I already did myself:
Changed the PCV valve
Cleaned the egr and cooler tank
Did an ISTA diagnostic and found 2 errors (one for EGR and one for DPF)
After cleaning the egr and cooler tank the egr error disappeared. DPF is still there.any 

I have been with this car since then to 3 garages including bmw wakefield. Noone could find the problem, everyone said everything is fine with the car. That's probably because everytime I was to their garages the car was not smoking at all.

Any ideeas on what else could I check ?

Links for ista results screenshots:
https://ibb.co/VLqz0G7
https://ibb.co/mC6vVyt

[aade]

Is this a diesel?

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Is this a diesel?

Smoking can be a number of factors, but if you're burning oil I would try to take care of that or it might clog your cats. That's very expensive to fix. A few things to check (if it's a gasoline motor):

1. Valve stem seals. Fiddly to replace, but not difficult. Take your time.
2. The PCV diaphragm, though you mentioned you'd replaced it in the past.
3. Check your oil pressure, seals and gaskets around oil filter housing and such things.
4. Do a compression test to make sure your valves are sealing properly at TDC, not sure how applicable this is on a diesel. Depending on the result from this you may have bigger work ahead of you, such as valve cleaning, busted head gasket or something like worn piston rings.

Since you're mentioning that this only happens when the engine is warm and that it stops when you turn it off and on again, suggests to me it's a rich condition from the ECU. Perhaps ISTA is right and that this isn't a shadow code. The EGR valve is one thing, but there's a sensor also. Check and see that it's operable. You should be able to run a multimeter in resistance mode to see whether it's likely electrically fine. If the sensor doesn't think your EGR valve is operable, that probably causes the motor to run rich and if you then don't have proper sealing there might be smoke.

[daimlerush]

Hi. Yes, car is a diesel.
Today I opened the bonnet again to see if I missed something..I noticed a pipe that looked it has a small ripped material on it and when I tried to twist it a little bit it snapped. After that i removed the small part and tried to snap it again using the same force i used when I checked the first time and it wont snap, I tried even harder and no snap..meaning the pipe was already damaged. One end of this pipe goes to egr pressure converter and is black in colour, the other end goes somewere behind the engine..couldn't tell were. There is another red one that looks allright. Do you think this could be the main reason for my car to smoke like that ?.
I will try to attach an image of how this pipe looks like.

[aade]

Hi. Yes, car is a diesel.
Today I opened the bonnet again to see if I missed something..I noticed a pipe that looked it has a small ripped material on it and when I tried to twist it a little bit it snapped. After that i removed the small part and tried to snap it again using the same force i used when I checked the first time and it wont snap, I tried even harder and no snap..meaning the pipe was already damaged. One end of this pipe goes to egr pressure converter and is black in colour, the other end goes somewere behind the engine..couldn't tell were. There is another red one that looks allright. Do you think this could be the main reason for my car to smoke like that ?.
I will try to attach an image of how this pipe looks like.

I really don't know much about diesels, so I will be careful with what I say.

Since you're suggesting that the behavior changes once you've restarted the car (I presume without allowing the motor to cool down), it says to me that you're reaching a rich condition. If the EGR doesn't work properly, the gases will have to go somewhere and I believe that somewhere is the exhaust in this case. If there's a lot of oil in these gases you'll end up clogging your NOX sensors and possibly also the catalytic converters themselves.

A hose that goes to the EGR, from somewhere on the block (probably similar to a crankcase breather valve or something like that) could make it so that the ECU thinks the EGR is inoperable. If the ECU is getting wonky values from applicable sensors, it's possible that it would try to set a rich condition.

However, if you're burning oil, I would also not rule out compression issues so you should check that. No idea how this is done on a diesel, but it can't be super different from a gasoline motor.

If that hose is broken, replace it. You probably need it anyway. RealOEM.com should give you a clue as to what the part number is.

[daimlerush]

Just failed on MOT today. Exhaust noxes are 3 times higer then maximum allowed.

[aade]

Just failed on MOT today. Exhaust noxes are 3 times higer then maximum allowed.

MOT is an emissions test?

Have you attempted to switch out your NOX sensors?