N54 single turbo runs extremally lean and misfires when getting into boost.


Jan 12, 2023
Have a 2009 BMW 335XI with 60k miles. Car ran fine, and had no issues. I decided to go with a big single turbo kit and all supporting mods. I do not have port injection, I am just running Index 12 injectors with a bucket less dual in-tank fuel pump. We are working on an E40 tune right now but every time the car gets into boost it misfires on cylinder 3 and 5. According to the log the car is running extremely lean but fuel pressure looks good. Plugs and coils are brand new (using NKG one step colder). Oxygen sensors are brand new. Valve cover gasket, oil filter gaskets, oil has all been replaced very recently. Really don't understand what is going on here. We are now in the works of putting on an N20 map sensor and if that doesn't work supposedly the DME might be bad?? Really want to figure out the issue without pouring money into places not needed. Let me know if you guys have any ideas! thank you.

Here is the most recent log.