[tafmasterpl]

Hello guys i have 2012 F30 N55 with weird issue for some time, related to random stalling. The car runs perfectly normal 95% of the time, it has full power, no leaks, no strange squeking noise or whatsoever. It has normal NON-rough idle start, this can happen randomly.
It happend to me on fully warmed up engine and barely warmed up engine and it only happens on low rpm like 500-1200, the lower the worse it gets, but it is very random, i observed it likely to happen when you are driving at traffic at low rpms, like 15-20 minutes at the traffic, on highways with 2-7k rpms it never happens.
I experienced it two times at traffic, when you are approaching the traffic lights, the rpm jumps a little bit between 600-1100 rpms and the engine shuts off, no errors are presents on the screen via idrive or ISTA, so i guess it must be something mechanical, i got no misfires or other problems, the only thing im gertting from time to time is yellow CEL with ISTA - 118401 - mixture is too lean so my guess is, it is about some air getting to engine, there are no other errors

My mechanic suggested that this might be related to PCV valve cover or valve cover gasket, and advised me to check if the oil cap is hard to unscrew, however its getting of easily, so we are still not sure what is going on.

Whats even more interesting when this starts to happen, the car will only stall and die when you will get to 500 rpms, then the engine is completely dead for 15-60 seconds and cannot start at all. The faster you start the engine the worse it runs at low rpm (500-1100), so for example if i will start the engine after 15 seconds it will barely run on low rpm, however if i will wait for 2-3 full minutes it will start perfectly fine like nothing happend with full power and will run smoothly even on low rpm, so it must be something related to air? or thing that is getting away quickly and is a cause of the problem.

Do you have an idea what might be the cause?

[thejeremyman9]

Mileage? Mods?

The lean code in itself suggests either a vacuum leak or potentially O2, but it would be weird for those to be intermittent.

[tafmasterpl]

242k kilometres, it has been modified in 2016, wagner intercooler, catless, downpipe, 361 hp @ 570 nm. Thanks for the reply mate!

[Billfitz]

242k? It's tired!
However, the three requirements are fuel, air and ignition. Stalling is most likely fuel related. I'd start with the low pressure fuel pump and work my way to the engine. The integrated fuel filter may be clogged.

[thejeremyman9]

Can you datalog? getting a log when the issue occurs might be the only way to narrow it down if theres no codes

[tafmasterpl]

Originally Posted by thejeremyman9

Can you datalog? getting a log when the issue occurs might be the only way to narrow it down if theres no codes

i think i can, i have Vgate 4.0 bluetooth and i can buy every log program on android/iOS that would be needed i already have bimmerlink + bimmercode, i even wanted to the log myself before, but there are literally million options in BimmerLink to choose from and there is no option to choose all and then filter it via Excel file (real shame) Im not sure which options i need to choose to log something valuable that could help us, could you narrow the list which options i should choose in which program ? That could be very useful thank you for your input mate!

Here are also few short videos that i recorded today, i finally was able to narrow it down, i hear obviously fuel injectors which is totally normal but for around 6-12 months there is...kind of knocking in the left side of the engine according to my hearing it is located at the bottom of the left side of the engine (i think its around center wheel cap height). Please play it at full volume as mostly fuel injectors are spraying but you will hear the knock? the rattle? im not sure how to call it english, but i would call it sounds...diesel like rattle? the sound is quite similar to the diesel engine. The videos were filmed with air conditioning/air system turned off, as when it is on it is mostly inaudible to hear.

Please take a look what you think it is?

[tafmasterpl]

snyone got an idea?