RSQ3 Engine Knock: Timing and Fuel Issues Explained

Having dealt with similar symptoms on my 2019 RS3, I can share some relevant experience as someone whos worked on several VAG engines. The symptoms you describe strongly point to carbon deposits in the combustion chamber, which can affect the knock sensor readings and cause the engine management to pull back ignition timing as a protective measure. This exact issue cost me 425 Euro to resolve completely. My repair process involved: Professional carbon cleaning service, Checking knock sensor functionality, Verifying engine timing, Testing fuel system pressure, Clearing stored error codes The reduced power and jerking during acceleration are classic signs of the engine detecting knock and adjusting timing to compensate. This often happens when carbon buildup interferes with proper combustion. Before proceeding further, could you share: Current mileage, Fuel grade youre regularly using, When you first noticed the symptoms, Any recent maintenance history Using the proper high octane fuel is crucial for these engines to prevent pre-ignition issues, but carbon buildup can occur even with the best maintenance practices. Once you provide those details, I can offer more specific guidance based on how my situation was resolved.

Having dealt with similar symptoms on my 2019 RS3, I can share some relevant experience as someone whos worked on several VAG engines. The symptoms you describe strongly point to carbon deposits in the combustion chamber, which can affect the knock sensor readings and cause the engine management to pull back ignition timing as a protective measure. This exact issue cost me 425 Euro to resolve completely. My repair process involved: Professional carbon cleaning service, Checking knock sensor functionality, Verifying engine timing, Testing fuel system pressure, Clearing stored error codes The reduced power and jerking during acceleration are classic signs of the engine detecting knock and adjusting timing to compensate. This often happens when carbon buildup interferes with proper combustion. Before proceeding further, could you share: Current mileage, Fuel grade youre regularly using, When you first noticed the symptoms, Any recent maintenance history Using the proper high octane fuel is crucial for these engines to prevent pre-ignition issues, but carbon buildup can occur even with the best maintenance practices. Once you provide those details, I can offer more specific guidance based on how my situation was resolved.

Having dealt with similar symptoms on my 2019 RS3, I can share some relevant experience as someone whos worked on several VAG engines. The symptoms you describe strongly point to carbon deposits in the combustion chamber, which can affect the knock sensor readings and cause the engine management to pull back ignition timing as a protective measure. This exact issue cost me 425 Euro to resolve completely. My repair process involved: Professional carbon cleaning service, Checking knock sensor functionality, Verifying engine timing, Testing fuel system pressure, Clearing stored error codes The reduced power and jerking during acceleration are classic signs of the engine detecting knock and adjusting timing to compensate. This often happens when carbon buildup interferes with proper combustion. Before proceeding further, could you share: Current mileage, Fuel grade youre regularly using, When you first noticed the symptoms, Any recent maintenance history Using the proper high octane fuel is crucial for these engines to prevent pre-ignition issues, but carbon buildup can occur even with the best maintenance practices. Once you provide those details, I can offer more specific guidance based on how my situation was resolved.

Having dealt with similar symptoms on my 2019 RS3, I can share some relevant experience as someone whos worked on several VAG engines. The symptoms you describe strongly point to carbon deposits in the combustion chamber, which can affect the knock sensor readings and cause the engine management to pull back ignition timing as a protective measure. This exact issue cost me 425 Euro to resolve completely. My repair process involved: Professional carbon cleaning service, Checking knock sensor functionality, Verifying engine timing, Testing fuel system pressure, Clearing stored error codes The reduced power and jerking during acceleration are classic signs of the engine detecting knock and adjusting timing to compensate. This often happens when carbon buildup interferes with proper combustion. Before proceeding further, could you share: Current mileage, Fuel grade youre regularly using, When you first noticed the symptoms, Any recent maintenance history Using the proper high octane fuel is crucial for these engines to prevent pre-ignition issues, but carbon buildup can occur even with the best maintenance practices. Once you provide those details, I can offer more specific guidance based on how my situation was resolved.

Thanks for the detailed suggestions. Just had the 150000km service done 2 weeks ago and currently at 156008km. Started using RON98 fuel exclusively after a mechanic confirmed pre-ignition was causing the knock sensor to trigger. The carbon cleaning suggestion makes sense since detonation issues often get worse with carbon deposits. Engine tuning might need adjustment too, since the piston slap noise is most noticeable during cold starts. Will try the diagnostic steps mentioned, especially checking knock sensor readings. Going to keep track of when the symptoms occur and under what conditions to help pinpoint the root cause. A full inspection seems necessary at this point to rule out any serious damage from the knocking. Does this warrant an immediate workshop visit or is it safe to continue driving while monitoring the situation?

Thanks for the detailed suggestions. Just had the 150000km service done 2 weeks ago and currently at 156008km. Started using RON98 fuel exclusively after a mechanic confirmed pre-ignition was causing the knock sensor to trigger. The carbon cleaning suggestion makes sense since detonation issues often get worse with carbon deposits. Engine tuning might need adjustment too, since the piston slap noise is most noticeable during cold starts. Will try the diagnostic steps mentioned, especially checking knock sensor readings. Going to keep track of when the symptoms occur and under what conditions to help pinpoint the root cause. A full inspection seems necessary at this point to rule out any serious damage from the knocking. Does this warrant an immediate workshop visit or is it safe to continue driving while monitoring the situation?

Thanks for the detailed suggestions. Just had the 150000km service done 2 weeks ago and currently at 156008km. Started using RON98 fuel exclusively after a mechanic confirmed pre-ignition was causing the knock sensor to trigger. The carbon cleaning suggestion makes sense since detonation issues often get worse with carbon deposits. Engine tuning might need adjustment too, since the piston slap noise is most noticeable during cold starts. Will try the diagnostic steps mentioned, especially checking knock sensor readings. Going to keep track of when the symptoms occur and under what conditions to help pinpoint the root cause. A full inspection seems necessary at this point to rule out any serious damage from the knocking. Does this warrant an immediate workshop visit or is it safe to continue driving while monitoring the situation?

Thanks for the detailed suggestions. Just had the 150000km service done 2 weeks ago and currently at 156008km. Started using RON98 fuel exclusively after a mechanic confirmed pre-ignition was causing the knock sensor to trigger. The carbon cleaning suggestion makes sense since detonation issues often get worse with carbon deposits. Engine tuning might need adjustment too, since the piston slap noise is most noticeable during cold starts. Will try the diagnostic steps mentioned, especially checking knock sensor readings. Going to keep track of when the symptoms occur and under what conditions to help pinpoint the root cause. A full inspection seems necessary at this point to rule out any serious damage from the knocking. Does this warrant an immediate workshop visit or is it safe to continue driving while monitoring the situation?

Thanks for the additional details. The mileage and symptoms you describe match what I experienced almost exactly. After my carbon cleaning at 155000km, I also discovered worn cylinder heads were contributing to the detonation issues. The knock sensor triggering combined with piston slap during cold starts strongly suggests carbon buildup has progressed beyond just a minor issue. In my case, continuing to drive resulted in increased damage that could have been prevented with immediate attention. The fact youre already using RON98 fuel is good, but the knock sensor readings are telling us theres still an underlying problem. With these engines, once detonation becomes noticeable, internal components can deteriorate rapidly. Based on my repair experience, I strongly recommend getting it checked immediately. When my engine showed these exact symptoms, waiting only led to more extensive, and expensive, repairs. The final repair bill jumped from around 800 Euro to 2100 Euro because I delayed too long. The cold start piston slap is particularly concerning as it wasnt present in my initial symptoms but developed later as the problem worsened. This could indicate the detonation has already affected internal engine components. Get it inspected before the weekend if possible. These symptoms combined with the recent service timing suggest a thorough combustion chamber inspection is needed asap.

Thanks for the additional details. The mileage and symptoms you describe match what I experienced almost exactly. After my carbon cleaning at 155000km, I also discovered worn cylinder heads were contributing to the detonation issues. The knock sensor triggering combined with piston slap during cold starts strongly suggests carbon buildup has progressed beyond just a minor issue. In my case, continuing to drive resulted in increased damage that could have been prevented with immediate attention. The fact youre already using RON98 fuel is good, but the knock sensor readings are telling us theres still an underlying problem. With these engines, once detonation becomes noticeable, internal components can deteriorate rapidly. Based on my repair experience, I strongly recommend getting it checked immediately. When my engine showed these exact symptoms, waiting only led to more extensive, and expensive, repairs. The final repair bill jumped from around 800 Euro to 2100 Euro because I delayed too long. The cold start piston slap is particularly concerning as it wasnt present in my initial symptoms but developed later as the problem worsened. This could indicate the detonation has already affected internal engine components. Get it inspected before the weekend if possible. These symptoms combined with the recent service timing suggest a thorough combustion chamber inspection is needed asap.

Thanks for the additional details. The mileage and symptoms you describe match what I experienced almost exactly. After my carbon cleaning at 155000km, I also discovered worn cylinder heads were contributing to the detonation issues. The knock sensor triggering combined with piston slap during cold starts strongly suggests carbon buildup has progressed beyond just a minor issue. In my case, continuing to drive resulted in increased damage that could have been prevented with immediate attention. The fact youre already using RON98 fuel is good, but the knock sensor readings are telling us theres still an underlying problem. With these engines, once detonation becomes noticeable, internal components can deteriorate rapidly. Based on my repair experience, I strongly recommend getting it checked immediately. When my engine showed these exact symptoms, waiting only led to more extensive, and expensive, repairs. The final repair bill jumped from around 800 Euro to 2100 Euro because I delayed too long. The cold start piston slap is particularly concerning as it wasnt present in my initial symptoms but developed later as the problem worsened. This could indicate the detonation has already affected internal engine components. Get it inspected before the weekend if possible. These symptoms combined with the recent service timing suggest a thorough combustion chamber inspection is needed asap.

Thanks for the additional details. The mileage and symptoms you describe match what I experienced almost exactly. After my carbon cleaning at 155000km, I also discovered worn cylinder heads were contributing to the detonation issues. The knock sensor triggering combined with piston slap during cold starts strongly suggests carbon buildup has progressed beyond just a minor issue. In my case, continuing to drive resulted in increased damage that could have been prevented with immediate attention. The fact youre already using RON98 fuel is good, but the knock sensor readings are telling us theres still an underlying problem. With these engines, once detonation becomes noticeable, internal components can deteriorate rapidly. Based on my repair experience, I strongly recommend getting it checked immediately. When my engine showed these exact symptoms, waiting only led to more extensive, and expensive, repairs. The final repair bill jumped from around 800 Euro to 2100 Euro because I delayed too long. The cold start piston slap is particularly concerning as it wasnt present in my initial symptoms but developed later as the problem worsened. This could indicate the detonation has already affected internal engine components. Get it inspected before the weekend if possible. These symptoms combined with the recent service timing suggest a thorough combustion chamber inspection is needed asap.

I appreciate all the input and detailed advice. After reading about the potential risks and comparing symptoms, I will not postpone this repair. Already scheduled a workshop visit for tomorrow morning. The correlation between knock sensor readings, combustion chamber deposits, and the piston slap noise makes more sense now. Especially concerning is how engine tuning and carbon buildup could be working together to create these issues. My main takeaway is that high octane fuel alone wont solve underlying mechanical problems. The rapid progression from initial symptoms to potential cylinder head damage in your case has convinced me to take immediate action rather than risk more extensive repairs. Will have them perform a complete diagnostic check focusing on: Carbon deposit inspection, Knock sensor function testing, Compression testing, Cylinder head examination, Full error code analysis The repair costs you mentioned have helped set realistic expectations for what this might involve. Better to address it now at 800 Euro than wait and face a 2100 Euro repair bill. Will update once I have the diagnostic results and know exactly what were dealing with.

I appreciate all the input and detailed advice. After reading about the potential risks and comparing symptoms, I will not postpone this repair. Already scheduled a workshop visit for tomorrow morning. The correlation between knock sensor readings, combustion chamber deposits, and the piston slap noise makes more sense now. Especially concerning is how engine tuning and carbon buildup could be working together to create these issues. My main takeaway is that high octane fuel alone wont solve underlying mechanical problems. The rapid progression from initial symptoms to potential cylinder head damage in your case has convinced me to take immediate action rather than risk more extensive repairs. Will have them perform a complete diagnostic check focusing on: Carbon deposit inspection, Knock sensor function testing, Compression testing, Cylinder head examination, Full error code analysis The repair costs you mentioned have helped set realistic expectations for what this might involve. Better to address it now at 800 Euro than wait and face a 2100 Euro repair bill. Will update once I have the diagnostic results and know exactly what were dealing with.

I appreciate all the input and detailed advice. After reading about the potential risks and comparing symptoms, I will not postpone this repair. Already scheduled a workshop visit for tomorrow morning. The correlation between knock sensor readings, combustion chamber deposits, and the piston slap noise makes more sense now. Especially concerning is how engine tuning and carbon buildup could be working together to create these issues. My main takeaway is that high octane fuel alone wont solve underlying mechanical problems. The rapid progression from initial symptoms to potential cylinder head damage in your case has convinced me to take immediate action rather than risk more extensive repairs. Will have them perform a complete diagnostic check focusing on: Carbon deposit inspection, Knock sensor function testing, Compression testing, Cylinder head examination, Full error code analysis The repair costs you mentioned have helped set realistic expectations for what this might involve. Better to address it now at 800 Euro than wait and face a 2100 Euro repair bill. Will update once I have the diagnostic results and know exactly what were dealing with.

I appreciate all the input and detailed advice. After reading about the potential risks and comparing symptoms, I will not postpone this repair. Already scheduled a workshop visit for tomorrow morning. The correlation between knock sensor readings, combustion chamber deposits, and the piston slap noise makes more sense now. Especially concerning is how engine tuning and carbon buildup could be working together to create these issues. My main takeaway is that high octane fuel alone wont solve underlying mechanical problems. The rapid progression from initial symptoms to potential cylinder head damage in your case has convinced me to take immediate action rather than risk more extensive repairs. Will have them perform a complete diagnostic check focusing on: Carbon deposit inspection, Knock sensor function testing, Compression testing, Cylinder head examination, Full error code analysis The repair costs you mentioned have helped set realistic expectations for what this might involve. Better to address it now at 800 Euro than wait and face a 2100 Euro repair bill. Will update once I have the diagnostic results and know exactly what were dealing with.