The Knock Sensor (KS) is mounted to the engine block. When spark knock, or pinging is present, then sensor produces a voltage signal which is sent to the ECM. The ECM will then retard the ignition timing based on these signals.
When a Knock Sensor problem is suspected, first perform a visual inspection. Most problems can be found in wiring harnesses and connectors.
Perform a basic knock sensor test as follows. To perform this test, you will need a timing light.
- Connect a suitable timing light to the engine.
- Start the engine and allow to warm up sufficiently.
- Position the timing light near the timing marks on the harmonic balancer.
- Locate the knock sensor.
- Using a suitable metallic tool, tap on the intake manifold or side of the engine block; whichever is closer to the knock sensor. Do not strike hard or hit the sensor directly, light tapping should cause the knock sensor to react.
- If the knock sensor is working, the ignition timing will begin to retard as you tap.
- If the timing does not change, you will need to check voltage at the knock sensor harness connector. Also, make sure the connector is clean and making good connection.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Raise and support the vehicle safely.
- Detach the harness connector from the knock sensor.
- Remove the sensor from the engine block.
Do not apply thread sealant to sensor threads. Sensor is pre-coated at factory applying additional sealant will affect the sensors ability to detect detonation.
- Clean the threads on the engine block, where the sensor was installed. Install the sensor. Tighten to 11-16 ft. lbs. (15-22 Nm).
- Attach the harness connector to the knock sensor.
- Carefully lower the vehicle.
- Connect the negative battery cable.