Selling advice

[ainarssems]

Just my 2p about knock sensors.
1. Old or poor fuel.
2. Carbon build-up in in combustion chamber due to historic use of poor fuel, mostly being driven short distances not getting up to temp or high oil consumption.
3. Knock sensors bolted down with wrong torque values or loose. Or something else loose on the engine vibrating away giving false knock reading.

My friends 3.7 was like that, sometimes showing error codes and in measuring blocks always showing high knock values and ignition timing retarded due to knock values. Car did not seem like cared before and he was always driving on cheapest Morrissons petrol. Put in VPower just for trying and values went down quite a bit. He could not be bothered and just went back to Morrissons fuel. Probably cost him more in increased fuel consumption due to ignition timing retardation than he saved in cost per liter.

[MikkiJayne]

Checking Elsawin, that knock sensor code does simply mean too much signal from the sensors, so either an electrical issue or the engine is actually knocking outside the bounds of what the ECU can handle.

I'm inclined to agree its probably old fuel if the car isn't getting used much. The S8, oddly, is much more tolerant to low octane fuel than you would expect. There's no discernible difference in mine using Tesco standard or momentum, although that may be because the engine only has 30K on it. I know Mike does see a difference in consumption on the good stuff. I mostly run mine on Tesco standard day-to-day and it doesn't knock at all. It only gets momentum for longer journeys. The 3.7 however absolutely hates cheap / low octane fuel because its mapped to burn as lean as it can for better economy. My original 3.7 would knock terribly if it had anything other than Vpower.

[Dempsey87]

Thanks for the feedback. I guess next step is to list it in the for sale section and see if anyone is interested. Would love for it to go to someone who will get it back to tip top shape.