Knock Sensor: Testing and Inspection

1984 Plymouth Horizon L4-97 1.6L SOHCSECTION Testing and Inspection

1. Connect a suitable timing light to the engine.
2. Start engine and increase speed to 1200 RPM.
3. Connect a suitable vacuum pump to the vacuum transducer. Set pump to 16 inches vacuum.
4. Tap on the manifold near the sensor. Using the timing light, check for a decrease in spark advance. The amount of decrease in timing is proportional to the strength and frequency of the tapping. The greatest decrease in timing will be approximately 11 degrees.


RENDER: 1.0x

NO RELATED

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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.