CARTRIDGE GP-TURBOCHARGER 7C6714 - Caterpillar

Detonation is engine knock that occurs after combustion has occurred. The excessive mechanical stress and thermal stress can reduce the service life of the engine. There are several possible causes of detonation. Examples are a rich air/fuel mixture, overload, a high compression ratio, and high inlet manifold air temperature.Combustion of the air/fuel mixture prior to the spark is a premature ignition. A hot spot in the combustion chamber can be the cause. Possible sources of premature ignition are deposits in the combustion chamber. Detonation can be the result of premature ignition. The premature ignition effectively advances ignition timing.Although a sensor may indicate the presence of detonation, the problem could be a premature ignition. An indication of detonation can also be caused by excessive mechanical engine noise.Detonation is only monitored between 9 degrees before top center and 40 degrees after top center. Doing so avoids detecting vibrations not related to detonation.For information on testing the detonation sensors, refer to the engine Troubleshooting manual.