S6 Performance Loss with Smoke: Timing and Knock Issues

Had similar symptoms with my 2014 Audi S4. The detonation and power loss issues were caused by heavy carbon deposits in the combustion chamber. The cylinder heads needed thorough cleaning and the ignition timing had to be recalibrated. The smoke and jerking during acceleration are classic signs of pre-ignition, often caused by carbon buildup affecting proper combustion. This was indeed a serious issue requiring immediate attention, as continued driving could have led to engine damage. The fix involved: Complete carbon cleaning of combustion chambers, Inspection and cleaning of cylinder heads, Adjustment of ignition timing, Switching to higher fuel octane rating, Reprogramming the engine control unit After the repairs, all symptoms disappeared. The engine returned to smooth operation with proper power delivery. Worth noting that carbon buildup is common in direct injection engines, requiring preventive maintenance around 80000-100000 km. Would recommend having a certified specialist diagnose and repair this, as improper timing adjustments can cause significant engine damage.

Thanks for sharing that solution. I actually ended up with similar issues on my S6 last month, rough acceleration and that telltale smoke that had me worried about pre-ignition damage. The piston slap noise was getting pretty bad too before I got it sorted. The symptoms you described match exactly what I experienced, especially the power loss from carbon buildup in the combustion chamber. Did the detonation issues come back at all after your repairs? Wondering if I should watch out for any recurring problems. Also curious about the total repair cost you ended up paying for the cylinder heads work and carbon cleaning. My mechanic mentioned this might need regular maintenance going forward.

Good to hear back about your S6. After getting the combustion chamber cleaned and timing reset, my engine knock issues never returned. The 425 Euro repair cost was worth every cent, took care of all the carbon deposits and restored proper combustion. The knock sensor now shows normal readings and the engine runs perfectly smooth. The mechanic explained that modern direct injection engines are prone to carbon buildup, but regular maintenance can prevent pre-ignition problems from recurring. Switching to premium fuel also helps reduce deposit formation. For preventive care, I now do carbon cleaning every 40000 km. The initial fix included a complete combustion chamber service and ignition timing adjustment, which stopped the detonation completely. No more power loss or rough acceleration since then. Make sure to monitor for any unusual sounds or performance changes, but with proper maintenance, these issues typically dont come back. The engine management system should maintain optimal timing now that the carbon deposits are cleared.

I took my S6 to a certified Audi specialist last week after reading your advice. The diagnosis confirmed heavy carbon buildup causing engine knock and messing with the ignition timing. The knock sensor readings were way off normal levels. The repair involved a full carbon cleaning service, combustion chamber inspection, and ECU recalibration. Total cost came to 580 Euro but the difference in performance is like night and day. No more pre-ignition issues or power loss during acceleration. The mechanic showed me the carbon deposits they cleaned out, it was pretty shocking how much buildup there was. They recommended switching to higher fuel octane and scheduling regular carbon cleaning every 45000 km to prevent future problems. Really glad I addressed this when I did. The engine runs smooth now with proper power delivery and no smoke. Will definitely keep up with the maintenance schedule this time to avoid any repeat issues.