I really need help! Please...

[E46318]

Hello guys,

My engine was stalling. Sometimes its just shutdown in the middle off the road and a red oil light was on. I had to ignite the car again to keep driving.
My mechanic said its a problem with mass air sensor. So we replaced it.
Now, the engine still stalling sometimes. When I stop on light traffic and press gas,the engine shutdown. So I went back to my mechanic. After checking the car he said I need to replace the engine. He said that the oil pressure is low and it can't be fixed. He unplugged something on top of the engine so I can drive without the problem with my engine going off. But the car has now power at all. I barely reach 100 kmh. I bought a OBDII and checked the car by myself,this is the errors I got:




Can anyone please explain to me what to do next? I'm pretty lost.
Don't know who to trust anymore.
Is it really can't be fixed? My engine is dying?

[jclausen]

If the lean faults were present at the original repair you need to smoke check then entire intake system, basically the oxygen sensors are reporting to the computer the mixture coming out of the engine has to much air. BMW's injection system uses metered air intake this is registere thru the airmass flow sensor any air after that that is caused by a leak, like a torn intake air bolt is unmetered air, lean faults are because of thenleak and the oxygen sensors are reporting the condition. So when people see the oxygen sensor reporting this and replace the sensor to have the fault come back are not understanding what the fault means. So I would start with the smoke check and as far as the oil pressure you would only know it's bad by in stalling a mechanical gauge and actually see what the reading is. I've had very few BMW over the years with actual poor oil pressure, on some engines that were just below the threshold of the switch rating, which I had in an e39 v8, in this case after watching the actual oil pressure the needle would jump up pretty high then settle to the correct rating, at like the pressure was a little below the minimum amount so we used engine flush, thinking the pressure relief valve was sticking for the high reading and used a slightly higher weight oil for the lower rating and it's been fine for over a year. So I'm not sure if your tech is up to the task to properly diagnos the car

[Muzz258]

+1 on the smoke test to find your vacuum leaks.

[MarcoZandrini]

+2 on the smoke test. You’ll need to find a shop that has a professional smoke machine. Also, the pre-catalytic oxygen sensor is considered to be a consumable item and needs to be replaced every 100k miles/160k kms.

[E46318]

First of all,thank you so much for your reply!
I couldn't find a smoke test on my country. Maybe I will try DIY,not sure yet what to do.
Maybe you can help diagnose the problem more accurate?

After I unplug this,the car drives much better and almost not stopping. But of course the car is lacking power. When it's plugged,I stop a lot. Specially on turns & after stopping on traffic lights and starting to drive:

(The plug under the cover,I have no idea how its called)



I checked with OBDII when its unplugged and thats what it shows:


I have checked spark plugs & ignition coils,looks fine.
Can all this be because of bad mass air sensor?
I bought a new one because my engine was dying in the middle of the road. Usually after speeding above 100kmh. EML light was turning on and I had to start the engine again.
Maybe all this info will spark some light on the problem and can help you diagnose more accurate. Where do I start? What to change first? Oxygen sensors? DISA? Fuel filter?
Or maybe DIY smoke test? What can I use as a smoke for the test?

[E46318]

If the lean faults were present at the original repair you need to smoke check then entire intake system, basically the oxygen sensors are reporting to the computer the mixture coming out of the engine has to much air. BMW's injection system uses metered air intake this is registere thru the airmass flow sensor any air after that that is caused by a leak, like a torn intake air bolt is unmetered air, lean faults are because of thenleak and the oxygen sensors are reporting the condition. So when people see the oxygen sensor reporting this and replace the sensor to have the fault come back are not understanding what the fault means. So I would start with the smoke check and as far as the oil pressure you would only know it's bad by in stalling a mechanical gauge and actually see what the reading is. I've had very few BMW over the years with actual poor oil pressure, on some engines that were just below the threshold of the switch rating, which I had in an e39 v8, in this case after watching the actual oil pressure the needle would jump up pretty high then settle to the correct rating, at like the pressure was a little below the minimum amount so we used engine flush, thinking the pressure relief valve was sticking for the high reading and used a slightly higher weight oil for the lower rating and it's been fine for over a year. So I'm not sure if your tech is up to the task to properly diagnos the car

+1 on the smoke test to find your vacuum leaks.

+2 on the smoke test. You’ll need to find a shop that has a professional smoke machine. Also, the pre-catalytic oxygen sensor is considered to be a consumable item and needs to be replaced every 100k miles/160k kms.

And again,thank you so much for your time & effort!

[whiskychaser]

You are unlikely to find much in the way of DIY smoke testers in the UK. Link below is to something I have used. You put a lit cigar in the port near the handle. The cigar will probably cost more than the kit
https://www.ebay.co.uk/itm/HAND-TRAN...4AAOSwH-daKlr7

Of greater concern is the low oil pressure. It could be a faulty oil pressure switch. If you cannot test it yourself, maybe get someone to do it?

It sounds like your mechanic just increased the idle speed to help prevent stalling. Not familiar with the N42 but it has got to have some form of idle control valve. Maybe get someone to look at that too