My 91 Turbo 945 seems to be having more trouble pinging. I read an earlier post about retarding the spark but wondered what else is there to look for? I have a new radiator, cooler thermostat, fresh oil change and still the pinging comes and goes. Last night in the cool weather I thought it was gone but today it seems like it wants to ping under acceleration almost all the time. The hoses look good but I am really scratching my head on this one - any help would be greatly appreciated!

Stop running cheap gas! Turbos need 89 octane minimum, 91+ is better for them.

And a fuel injection cleaner would probably help. Techron is one that actually works, not just snake oil. Helps get deposits off of injectors and intake valves. The intake deposits can create pre-ignition or pinging.
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I would check the temp sensor for proper resistance. Then check the knock sensor. Cheap gas should not ping a turbo, not unless you are running more than 8 lbs of boost, and then only on a hill would it ping. Your compression is not high enough. If you have lots of miles on it and your oil consumption is up, put some ice cubes in your winshield washerfluid and pour it in. Then hook to your vacuum port for the breather pipe. Get on the highway and use your washer fluid to clean any build up of carbon in the cylinders out. If that doesn't work I have plenty more ideas. Pauli