Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Knock Sensors: Notes
Knock Sensors are required to prevent detonation (pinging) from damaging the engine. The EMS2000 will retard the ignition timing (cylinder selective) based on the input of this sensor. Detonation occurs due to:
- High Compression Ratio
- Poor Quality Fuel
- High Level of Cylinder Filling
- Maximum Timing Advance Curve
- High Intake and Engine Temperatures
- Combustion Chamber Carbon Build-up
The knock sensor is a "Piezo-electric accelerometer" producing an output voltage proportional to mechanical vibration (knock) produced by the engine. Knock is caused by high-pressure waves of uncontrolled spontaneous combustion of gasses in the cylinder.
The EMS2000 receives a signal from the knock sensor, filters out any noise and calculates if the engine is knocking. During knock the crystal oscillation increases, the EMS2000 compares the signal received to known signal profiles in the memory.
From the camshaft and crankshaft signals supplying information regarding the position of the engine in it's cycle, the EMS2000 is able to determine which cylinder is knocking and will retard the ignition, on that particular cylinder until the knock is eliminated. It then gradually advances the ignition again towards the original setting until knock occurs again.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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