E90 N54 misfiring on cold starts

[walross 0]

During cold starts I get slight missing and rough idle. If I don't leave the car to idle for a minute or two before driving the car it will seriously misfire as soon as I load the engine, throwing multiple misfire codes, cylinder shutoff etc, limp home mode. Even if I let off the throttle and reduce load it will just continue to misfire. If I pull over and restart the car its usually fine immediately after. It blows a little smoke cold and I notice the exhaust tips are getting really black like its running too rich or something? Comes good when warm. Twice I have instances too where the car is up to temperature. I go to plant it from a standstill (high load, low rpm) and again it sends it shuddering into multiple cylinder misfires etc).

I have recently replaced Plugs, Coils and upgraded to brand new OEM index 12 injectors. Before the injector change I was getting misfire codes, shuddering, spluttering on start ups. There has been a real improvement. But still nagging issues. Vanos solenoids and boost solenoids also changed reasonably recently. I run the car nearly entirely on Gulls E10 98 octane. Colleagues suggest that maybe its shitty fuel? Thoughts on that remark?

Car is running jb4 with MHD BEF. Logs for LPFP and HPFP pressures look really good at start up and running so I think it would be clutching at straws to blame them. But nothing is impossible right?

Codes are repeated individual cylinder misfires including 29CC (several cylinders) and 29DC (cylinder injection shutoff).

But have also had 2x 29F1 (Fuel pressure, Plausibility) and one 29F3 recently (Faulty low fuel pressure sensor)

Also had 2B2C come up frequently and im not sure what that is?

Car has only 70,000km on the clock. Boosts well (when this isn't happening). Seen in logs it easily reaches 17psi targets. Does have horrendous waste gate rattle though.

I feel like walnut blasting might come up as a recommendation. Who does it in or near taranaki? Is hamilton my closest bet? I have bought a catch can to be fitted too.

Your thoughts are appreciated!

 

[brenthay 10]

I use Gull E10 in my 335i with zero issues!

[Driftit 2078]

Just letting you know that Gull changed their 98 to 95 after lock down. And it's sh*t. Most should be back on 98 by now but I highly doubt they drained the tanks. Probably just mixed it. 

Edited July 25, 2020 by Driftit

[walross 0]

22 hours ago, F10er said:

Did you code the injectors to the DME?

I personally didn't but I took it to a mechanic that said they had the right software to do it. So I am trusting they did. Is there anywhere you can look at the calibration factors using Bavarian technic or MHD?

Update: I reset all adaptations and it currently *knock on wood* seems a lot better! The starts are waaaaay calmer, car feels smoother. But still not perfect. Just the odd subtle hiccup a few seconds after start where it still does a miss or two.