RS7 Engine Knocking with Power Loss and Heavy Smoke

Had similar symptoms on my RS5 last season. The knock sensor was triggering constantly due to carbon deposits in the combustion chamber, causing the ECU to pull timing aggressively. This led to power loss and engine knocking under load. The root cause was carbon buildup creating hot spots, leading to pre-ignition issues. The smoke during acceleration was a clear indicator of oil passing through the combustion chamber, likely due to clogged PCV system contributing to the deposit formation. The fix required: Complete carbon cleaning of combustion chambers, New knock sensors, PCV system replacement, Reset of ignition timing adaptations This was a serious issue that needed immediate attention to prevent permanent engine damage. Piston slap can develop if these symptoms are ignored, potentially leading to complete engine failure. Would strongly suggest having a compression test done and getting the carbon deposits cleaned professionally. The longer you wait, the more extensive and costly the repair becomes.

Thanks for the detailed info on the carbon buildup issue. Made a lot of sense when you mentioned the knock sensor triggering and ECU adjustments. Just wanted to follow up since my Audi had almost identical symptoms, especially that engine knock during acceleration and the smoke issue. Pretty worried about potential cylinder head damage at first. Got it fixed at a specialist shop that really knew their way around high performance engines and fuel octane requirements for these cars. The engine tuning and timing is now perfect after the repair, but curious what repair costs you ended up with? Also wondering if youve had any recurring issues since the work was done?

Glad to hear you got it fixed. After my repair, the engine knock and detonation issues completely disappeared. The combustion chamber cleaning and sensor replacement cost me 425 Euro total, which seems fair given the complexity of accessing those components. The shop did excellent work targeting the carbon deposits. No recurring problems in the past 15000km. The knock sensor works perfectly now, and the engine runs smooth even under heavy load. The smoke issue is completely resolved too. Just make sure to use high-quality fuel to prevent future carbon buildup in the combustion chamber. Regular maintenance will help avoid these issues from developing again. Worth every cent considering how well the car performs now, no more power loss or rough acceleration. Your experience matches mine almost exactly, right down to the initial concerns about cylinder head damage.

Finally got my car sorted and wanted to share the outcome. Found a specialist shop that really knew their stuff with high performance engines. They confirmed it was heavy carbon deposits causing the knock sensor issues and messing with the ignition timing. Total repair came to 680 Euro including parts and labor. They did a thorough job cleaning the combustion chambers, replaced the knock sensors, and fixed some related vacuum issues. The cylinder heads were actually fine, just needed a good cleaning and proper engine tuning to get everything back in sync. Been driving it for about 2000km since the repair. Engine knock is completely gone, acceleration is smooth again, and no more smoke under throttle. Running much better than before, almost like new. Definitely learned my lesson about getting issues checked out early before they turn into bigger problems. For anyone else facing similar symptoms, dont wait around hoping it will fix itself. That knock sensor triggering was a serious warning sign that needed immediate attention.