Pinging and pre-ignition are not the same thing, although pre-ignition can cause pinging. Pre-ignition occurs when the air fuel mixture ignites before the spark plug fires. This can be caused by hot spots forming in the combustion chamber (for example due to carbon glowing red hot) poor fuel quality (low octane), excessive cylinder head temperatures, etc. Note that pinging can also be caused by excessively advanced ignition timing, in which case it is notcaused by pre-ignition but by incorrect timing. Pre-ignition if sustained may cause engine damage and should be investigated.
Using the term detonation opens a door to another discussion...
Steve
