I have 2002 WRX. It has recently started registering - negative knock correction on take off.

1. The - KC only occurs on clutch take up from stand still.
2. There is no - KC anywhere else in the rev band

I surmise there might be a loose object confusing the KC. What should I check?

 

I would have thought it's just picking up the noise of the clutch engaging/gearbox noise..? Especially as it's OK elsewhere in the rev range..!
I'm sure someone with more knowledge will contribute as to whether this could be the case (or not)..

 

Assuming the KC you are seeing is being displayed on a data monitor, negative KC is not good as it indicates that the ECU is retarding because it's detecting something it doesn't like.

I recently posted asking about knock correction on a data monitor versus knock activity detected by a knock link. Interesting info.

https://www.scoobynet.com/knocklink-...ock+correction

 

The engine is not detting.

Definitly something loose in that area. Knocklink showing knock on off throttle coasting.

 

Interesting link..

T2T, what's your current spec..?

 

Plumb in det cans, might give you better idea of what's going on (noise wise) and another form of safety check for det later - its what all the pros use.

 

A noisy release bearing can be picked up by the factory knock sensor and cause the ecu to pull timing during take off. Not sure if it will cause the knocklink to light on off throttle coasting though. Do you know if the bosch sensor is ok or not, is it fitted in the correct place, has it come loose ? Strange that the knocklink sensor seems to be detecting something that the factory one isn't, or the ecu isn't responding to.

You can check for det with det cans as already mentioned. In the absence of det, and with known good knock sensors, I would have it looked at professionally as a knocklink can also be triggered by mechanical problems.

 

Thanks Ken. It is definitely something loose on the gearbox.

 

Is the spring connected to the clutch operating arm ? If not then it may rattle a bit.