so the tp (efi) seems to have developed some pinging on light throttle, seems to mainly happen when i change gears and/or when no more than 10% throttle is used, though seems to be worse on the gear changes.
it only lasts for a split second and if i floor it it goes away immediately.
timing is advanced to about 15 degrees and has been running fine.
ambient and air temp seems to have no bearing.
any idea?

Obviously its not running fine if it is pinging. Set the ignition timing to factory specs or run higher octane fuel.

set the timing to 13 degrees btdc at an idle of 800 rpm
all accesories and air conditioner off

tryed 13 degrees after the head change and it was really slow. it has up to this stage been running fine on 15. what i cant understand is why it knocks for a moment and then with no change in load or throttle position it stops, surely the knock sensor should retard the timing alot quicker if that was he problem.

that a tough question then

could the problem be in the dissy module

check the fuel pressure regulator/ faulty injector

the TP didnt come out with a knock sensor like the TR/TS 4 cyl

can you tell which cylinder is knocking if you pull the plug leads off one at a time

yeah im not sure, not really in a position to be checking stuff as im away atm. migh throw some injector clean it her and see if it makes any difference.