hey all ~
Pretty much trying to nail this on the head as to what to change / replace and look at.

Car not relevant - engine k20a (JDM EP3R). Stock engine stock everything 49xxx miles. Use 98 RON fuel here in Oz ( 93 in the US?).

Noticed that the engine makes a distinct rattling/pinging under medium throttle in 1st and 2nd gear - this noise disappears under heavier load and full throttle.
Ideal situation to hear this , is a slow cruise up a suburban street in 2nd gear then punch it alittle and you will hear the *rattlerattlerattlerattle* as your foot presses further then the noise disappears. No other time , rpm or situation this happens. Engine generally feels strong , the clutch was close to dead ( car is sitting waiting for subframe to be reinstalled as we speak ).

Short of telling me to use better fuel ( there isnt here in OZ , 98 is the top leve ) what else could i be looking at adjusting/changing ? Car is up on stands subframe off so all good to access. VTC issue ? auto-tensioner old/failing ?

Any thoughts !

 

I do not think the pinging you are hearing is detonation considering your octane rating is high enough for that engine/ ecu. Are you still using a PCV valve? The rattle may not have anything to do with the internals of the motor. Check for something vibrating under the hood while working the throttle at the RPM where you usually hear the noise.

 

Still using the oem pcv system.

As the car is on stands and I'm waiting for parts so i thought to replace what I can while it's apart