Detonation (Engine Knock)
Detonation is uncontrolled explosive burning of part of the mixture after the spark, heard as a metallic pinging or knocking.
What is Detonation (Engine Knock)?
It happens when pressure and temperature make the end gas ignite on its own. Low-octane fuel, carbon deposits, overheating and wrong timing increase the risk. Modern engines detect it with knock sensors. Engines with knock control will retard ignition timing to stop knock, which reduces power and efficiency; repeated knock retard in live data is a clue.
How it works
Shock waves hit the piston and chamber walls, causing the noise and heat.
Why it matters for your car
Severe detonation can damage pistons, rings and head gaskets. Use the specified fuel and keep the cooling system healthy.
Other terms
- Atkinson Cycle
- Body Control Module (BCM)
- Bolt Pattern (PCD)
- Camshaft
- Carbon-ceramic Brakes
- Cargo Barrier (Dog Guard)
- CV Joint (Constant Velocity Joint)
- Emergency Lane Keeping
- Exhaust Backpressure
- Hatchback
- Injector Coding
- Injector Leak-off Test
- LED Headlight
- Oil Catch Can
- Port Fuel Injection
- Positive Earth Electrical System
- Power Steering Pump
- Purge Valve
- Space-Saver Spare Wheel
- Voltage Drop Test