762 Knock Sensors

If a knock sensor of the type described in Chapter 5 is correctly fitted, i.e. not overtightened and the electrical connections are good, the sensor is likely to be very reliable. However, if 'pinking' should occur it is probable that the knock sensor may be failing to produce a signal. In order to test the knock sensor, the sensor can be activated by tapping the cylinder block with a small spanner, or similar object, close to the sensor. It should be possible to observe the effect on an oscilloscope screen.

Figure 7.16(a) shows the oscilloscope probe connected to the signal lead of the sensor, the type of pattern, together with a maximum voltage and frequency that

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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