Pinking, also known as pinging, is a fault which occurs in spark-ignition engines.

Pinking occurs in the combustion chamber after the spark has ignited some of the air/fuel mixture. As part of the mixture burns the temperature and pressure of the unburned air/fuel mixture in the rest of the combustion chamber rises, until eventually it is so hot it explodes. This uncontrolled combustion produces a ticking or tinkling noise which is known as pinking or pinging.

In extreme cases the uncontrolled combustion can cause serious damage to the valves, piston crown and cylinder head.

See also detonation, pre-ignition