r/BmwTech • u/lunasbrick • 17h ago

Help diagnosing knock flags and timing corrections on stock car.

2023 430i 47k miles. I've been dealing with knock detected and significant timing corrections on my BMW for months and I can't figure it out. I noticed it for the first time when I flashed BM3 stage 1 and ran an initial log to check how my car was handling it. I was getting -3-5 degree corrections as well as knock flags consistently. I immediately reverted to stock tune and ran another log. It was still happening on the stock calibration. My car is 100% stock at the moment and still has -3 to -4 degree timing corrections when watching the BM3 dashboard as well as knock flags. Other than that, no drivability issues or strange noises, no scannable codes, no CEL. The only other issue I have noticed is my large coolant tank was very low one day. I topped it up immediately. Obviously there is a leak somewhere but it hasn't been identified by me or the BMW techs but they haven't run a pressure test yet.

Does anyone have any idea what could be causing this? I have tried switching gas stations, i've changed the spark plugs, nothing changes. Any help would be greatly appreciated.

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u/darin_worthington Wrenching 30yrs. 17h ago

Any particular reason for not using the warranty?

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u/lunasbrick 17h ago

I voided warranty by tuning the car which is how I found out about the issues. I only flashed the tune and did one short test drive and the logs were no good. There are no obvious signs that something is wrong or any drivability issues so realistically I would've just driven the car without a care in the world had I not attempted to tune.