Technical Knock Sensor
- Thread starter TheCROW
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Technical Knock Sensor
Modern cars run their ignition timing pretty advanced and close to the edge where the engine would feel like it's "knocking" or clattering. The knock sensor detects this and retards the ignition a fraction until it gets to a point where the ignition is advanced as far as it can go without the knocking occuring
"Knocking" can damage an engine over a period of time
"Knocking" can damage an engine over a period of time
NumanR
Established member
The technical term is "Pinking", the knock sensor is a Piezo crystal device which picks up the pinking frequency before the human ear can detect it. The sensor sends the signal to the ecu like Deck says and the ecu then decides whether to retard the ignition or not. It is required due to the weak mixtures modern engines use and varying quality and RON rating of petrol throughout the vehicles anticipated operating area. Because it is a Piezo crystal device it is tuned by the torque of the centre fixing bolt, so if you ever fit a new sensor make sure the mating surface is clean and that you torque the fixing bolt up to the correct torque.
NumanR said:
And only way to test is resistance but you can contact to voltmeter & hit it,knock sensor not the meter
(only tests for open circuit though as no official measurments are given)
Last edited:
NumanR
Established member
I prefer to hit the meter T, I find it much more therapeutic.
I prefer throwing hammer across workshop......duck!!!
Other types of tantrum include kicking the toolchest,punching the toolchest(not good...hurts),kicking workshop doors,swearing 'rather' loudly,going for a walk around the block
Other types of tantrum include kicking the toolchest,punching the toolchest(not good...hurts),kicking workshop doors,swearing 'rather' loudly,going for a walk around the block
