[fyllt]

Hi,

I have a problem with the engine and am not sure what's going on. Long story short: 3 months ago I first saw RPMs on cold start started to shift up and down and it started vibrating a little more than usual. The vibration did go away around 50c temps and the engine sounded normal again. The engine week after a week started to vibrate more and more on cold start and 2 weeks ago the first time I noticed that the engine started running rough even after reaching 50C. A week ago I started to notice also knocking on a cold engine, but on hot it goes away.

Now just to rule some things out, I did a lot of testing/live data tracking when the engine was fine, just to know it better, and now that this thing is happening(cold start vibration, knocking when cold, hot engine vibration) I can say that something's up with air/fuel? Here's something interesting, when the engine is hot MAF sensor shows that it's pulling 500mg air, but when it goes down to 250-300mg it works perfectly, with no vibrations, no knocking. Has anyone had a similar problem?

1. The computer shows 0 errors.
2. I changed the glow plugs and relay, but on a cold start, it doesn't sound like glow plugs or relay again and it wouldn't make a difference to a hot engine.
3. I installed a new crankshaft pulley it does make the knocking noise when it's on its way out, but that didn't help and it still doesn't explain why the engine runs normally when air mass changes to 250-300mg.
4. It's not timing chains related either, I changed them 20,000 km ago and it's not timing chain sound, and again doesn't explain why the engine runs perfectly on 250-300 air mass.
5. The turbocharger was changed to a new one 10,000km ago and it's showing same boost as before this problem.
6. Forced even DPF regeneration - didn't help.
7. Unplugged EGR, didn't help. (also I tried to 100% open and fully 0% close it via computer. The engine sound changes, but it still sounds not normal)
8. Tried disconnecting the MAF sensor - didn't help. Installed a new bosch MAF - didn't help again.
9. Tried disconnecting injectors while the engine was running, but none of them made a huge difference, the engine was sounding pretty much the same with each disconnected.
10. The engine reaches ~94C temps pretty fast and never drops below 90C, so all thermostats are working correctly, but again that doesn't explain the weird cold start then.

As you can see I tried a lot of things and just can't figure it out, car pulls like brand new, no problem there, but when at idle or cold start that's when the most annoying sounds and feeling(vibration) I get via seat, foot, steering wheel. Also, another thing I noticed is that my car consumes a lot of fuel, in the city around 14 liters per 100km, but on the highway, it takes only 5.5l per 100km. No tuning was done to the car, everything is in place as it should be.

I tried to make this post as short as possible, but it still ended up a bit long. Anyway, any ideas guys? My heart tells me that it's probably injector related, but unplugging each one didn't make a huge difference and on bimmer-tools where you can check injectors, the values are all good...

P.s. I change the oil quite often every 5-6k km(3-4k miles) when I change the oil I also change all filters(air, fuel, oil).

Or maybe something happened to DDE? I mean the computer of the engine?

Thank you.