Combustion of the air/fuel mixture prior to the spark is a premature ignition. This is usually caused by a hot spot in the combustion chamber. Possible sources of premature ignition are an incorrect spark plug, an incorrectly installed spark plug, and deposits in the combustion chamber. Detonation can be the result of premature ignition. The premature ignition has the effect of advanced 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.
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Detonation sensor (1) Accelerometer | |
The new detonation sensor consists of an accelerometer (1). Make sure that the connectors and the wiring are in good condition.
The operation of the detonation sensor can be easily tested.
Use a screwdriver to tap the engine block next to the accelerometer. If the detonation increases, the sensor is operating properly.
Monitor the level of detonation while you wiggle the wires for the detonation sensors at the ends of the engine harness. When possible, wiggle the wires for the detonation sensors throughout the engine harness. If the level of detonation changes, there is a problem with the wiring.
If the detonation sensors generate a diagnostic code for a problem with the electrical circuit, refer to the Electronic Troubleshooting manual.