General Motors Detonation is a form of abnormal combustion in automotive engines that occurs when the air-fuel mixture ignites in an uncontrolled manner. Typically, detonation happens when pressure and temperature inside the engine cylinder become excessively high, causing the fuel to ignite prematurely, before the spark plug fires. This premature ignition leads to a knocking or pinging sound, reducing engine efficiency, causing poor performance, and potentially leading to long-term engine damage, such as worn pistons or cylinder heads. GM works to reduce detonation through advanced engine designs, better fuel management, and knock sensors that adjust engine timing to avoid the problem.