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      11-09-2019, 01:54 PM   #2686
RileyMac
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Drives: 2008 BMW 335xi
Join Date: Nov 2019
Location: Champaign Illinois

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Top end noise

Hi there folks, first post here

I'm experiencing an odd noise that seems to be coming from the top end. I believed it to be an injector because I'm experiencing some poor fuel economy. While I was going to be in that area I decided to do plugs and coils because I figured they may be fouled from the leaky injector. A couple plugs smelled like gas so I do believe this is part of the issue. Cylinder 6 was throwing a misfire code which I thought was injector based, turns out its coil was grounding. Changed the coil and the misfire code went away and the engine is running perfectly smooth. Only issue is the strange noise is still there. I'm attaching the video (or attempting to at least, been a while since I've used a forum's interface) in the hopes more experienced ears can help diagnose.

I should mention I already thought it to be rod knock and had the oil tested which showed no metal.

I plan on doing the injectors anyway just wondering if I should pickup anymore parts. Based off my research I have narrowed it down to a couple culprits:

Boost solenoid
Vanos solenoid
HPFP
The ac compressor
Waste-gate rattle (it is rpm dependent and occurs on decel when the rpm's pass 3k)

Thanks for your time, any advice is appreciated
Riley

https://youtu.be/NTBJLL-k_nk
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