Camshaft position sensor can be started without signal, but after starting, the idle speed is unstable, the acceleration is poor and the fuel consumption increases. The crankshaft position sensor has no signal, so most vehicles can't start normally, but some vehicles can start, such as Jetta 2 valve EFI vehicle, whose program is designed to replace the signal of camshaft sensor after the crankshaft position sensor fails. However, after starting, all the performances are reduced and the engine speed can't go up.

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Introduction of common sensors:

1, type: it belongs to a type of engine speed and crankshaft angle sensor, which is also commonly known as cylinder identification sensor.

2. Principle: The timing of engine ignition and fuel injection is mainly determined by collecting crankshaft angle and engine speed signals. In order to distinguish their performance in work, we generally use the logo of CIS for identification. Carry out the work of fuel injection control, ignition timing control and deflagration control according to the corresponding working sequence.

Second, the photoelectric sensor is introduced:

1. Structure: It is mainly composed of signal panel (i.e. signal rotor), signal generator, distributor, sensor housing and wiring harness plug. The given task is received, transmitted and executed by signal rotor and signal sensor.

2. Principle: First, the signal of the model dial is transferred to the transistor of the LED, and then the corresponding electrode output voltage is concentrated. Generally, the voltage is 0. 1 v-0.3v-0.3v. At this time, the LED transistor will emit 4.8V——5.2V Finally, when the corresponding signal is transmitted through the rotation of the signal panel, a G signal sensor will generate1signal and a ne signal sensor will generate 60 signals.

Brief introduction of magnetic induction sensor;

1. Principle: When a given magnetic force passes through a permanent magnet and then corresponds to the S-level of its magnet, an alternating electromotive force will be generated through periodic changes. When the signal rotates clockwise, the air gap decreases, the magnetic resistance decreases, the magnetic flux φ increases, the magnetic flux change rate increases, and the induced electromotive force E is positive.

2. When rotating to the middle alignment position, the magnetic flux is constant, the magnetic flux change rate is zero, and the induced electromotive force E is zero; When rotating clockwise, the air gap increases, the reluctance increases, the magnetic flux φ decreases, and the electromotive force E is negative.

3. Attention: Pay attention to the structural characteristics of Ne signal generator, the generation principle and control process of speed and angle signals, the structural characteristics of G signal generator, cylinder identification and TDC signal generation principle and control process.