I have a 1992 240+t that I can’t get to stop pinging, I never had the problem then after dealing with some overheating issues I ping on 12psi of boost. I run 93 octane and it doesn’t seem to ping on 6psi but if I go any much higher than that I start to ping. Any suggestions? Also the car was converted to I believe LH 2.2 or LH 2.4.
I should add that if the car is not fully warmed up there is no pinging, along with I have already tried replacing the spark plugs.

 

A solution for pinging - is to retard the timing - which is not adjustable.

A 92 240 was not offered with a turbo in any market. So where did this "turbo" setup come from? Transplanted from a 740/940? Those did use efi fuel injection - the early 80's 240 turbos used CIS.

Do you have an intercooler? (that would have an effect on pinging) How is your boost adjustable? (I trust you have a gauge - the 240 turbo gauge in the center cluster or an aftermarket one - just curious)

And you mentioned overheating - I have seen many melted temp sensors (for the fuel injection) after an overheating event, perhaps the knock sensor (which adjusts the timing to prevent pinging) was damaged during your overheating event.