Originally Posted by rking117
that is Direct Injection. The Newer vehicles have it and it is loud with the hood open. Almost sounds like a diesel. It is normal
I was going to say that.
These new DI injectors run at a much higher pressure than non DI injection systems. And as I understand it, and I may be wrong, per reading up on the matter the fuel mixture as it leaves the injector is under such pressure that it actually creates a mini sonic boom...in this case it sounds like a tick. Add to it that it's occurring in a metallic tube and it just gets louder.
What gets me and I applaud BMW for this, they did not install a plastic insulator over the engine block to cut down on the noise.