Factory factors affect engine knock (Dieselpartsworld) 2016-01-19    

Factory factors affect engine knock:
1, to reduce the compression ratio (out of the factory is not good to do, the 307 factory has been done, which is to reduce the power consumption and increase the fuel consumption in exchange for);
2, adjust (reduce) the ignition advance angle (in the 4S can also handle, which to take a lot of bad influence for), ignition advance angle in addition to and original factory settings, and many factors related, such as CKP crankshaft sensor gap inappropriate; loose CKP; temperature sensor damage; load engine; ECU damage; spark plug inappropriate; 3, check the knock sensor is normal or not, whether the damage and interference; 4, whether the user or other special circumstances.
Engine knock how to do how to repair check it
For knock phenomenon inspection, 4S or repair plant in general by a sensor with a high frequency microphone to check if you can hear directly with the ear, to prove that the knock has reached a very serious point.
We can also check with the car:
1) simulation of vibration method
In the check of the knock sensor, the cylinder near the knock sensor can be knocked lightly, and the engine speed should be decreased when it is tapped. At this time, it is necessary to open the throttle valve and stabilize the engine, so as to increase the engine speed, the ignition timing is advanced, and the ignition timing is delayed. If the knock sensor near the tap, the ignition timing and speed of the engine has no effect, then the application of the meter to check.
2) check the power supply voltage of the knock sensor
Switch off ignition, wait 10 seconds, remove the knock sensor plug and socket, and then turn the ignition switch and the engine can not start), the DC voltage wiring harness measuring signal output terminal and a signal circuit between terminals should be 1 - 4V, or else that there's something wrong with the line.
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3) check the knock sensor function
Method 1: the engine running, connect to the knock sensor wire, slow to improve the engine speed to min / 3000r, while the use of universal meter voltage profile measurement. If the voltage increases, it indicates that the knock sensor is faulty.
Method two: engine running, connecting the knock sensor wire, with about 12b of the hammer gently tap the exhaust manifold, while the use of universal meter voltage profile measurement. If the voltage instruction value fluctuations occur, it indicates that the knock sensor fault vehicle sensors are input device of computer system of automobile, the automobile running in various conditions of information, such as speed, medium temperature, the engine is running condition and converted into electrical signal transmission to the computer, so that the engine in the best working condition. There are a lot of sensors in the car, which should not only consider the sensor itself, but the whole circuit of the fault should be considered. Therefore, in fault finding, in addition to check sensor, also check wiring harness, connectors, sensors and electronic control unit of the circuit.