There could be many reasons for the "pinging" or detonation. Yes, enriching the fuel mix does help. It does this by the cooling effect of the unburnt fuel taking the heat away kind of like evaporation cools you down if you are doused with water on a hot day. To determine if you are running lean, the best ways to determine this would be either by "plug reading" or by the use of a wide band O2 meter. By the way the detonation will sometimes show up as wear or small specs on the plugs when you read them, it depends how bad the pinging is. Also, you have to realize that the main cause of the pinging is a combination of excess heat and/or incorrect ignition timing. Causes of excess heat; poor water circulation or not enough of it. Too much compression (either by engine design or from excess carbon build up in the combustion chamber) Causes or incorrect timing: Ignition components that are worn or weak or just an incorrect advance curve. An example could be weak springs in the distributor or a weak coil etc. Having the wrong plugs. bad wires etc. all could contribute to pinging. Ways to counter pinging. Increase engine cooling, internal and external. Use gas with more octane. Get rid of carbon deposits. Make sure the ignition timing is spot on and that the ignition system is up to par. Lower the compression ratio if needed.
