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Chongqing Benhai Electronic Techonlgy Co.,Ltd
Phone£º18121066650
Contact: Mr. Mu.
Website: www.cqbhdz.com
Company Address: No. 27 Lailong Second Street, Fenghuanghu Industrial Park, Yongchuan District, Chongqing.
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common problem |
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| Common fault diagnosis and troubleshooting of engine ignition system |
| RELEASE TIME£º2025/9/6 SOURCE£ºChongqing Benhai Electronic Techonlgy Co.,Ltd READING£º49070TIME |
1£º The four basic principles of automobile fault diagnosis:
1. The principle of simplicity before complexity, and easy before difficult
2. The principle of thinking before acting and getting familiar with things before they arise
3. The principle of first up, then down, and first outside, then inside
4. The principle of backup before use and code priority
2£º The basic methods of automobile fault diagnosis:
1. Inquire with the user about the time, phenomenon, and circumstances of the malfunction, the cause of the malfunction, and whether it has been repaired or disassembled.
2. Preliminarily determine the scope and location of the malfunction.
3. Retrieve the fault code and identify the content of the fault.
4. Perform maintenance according to the fault range displayed by the fault code, paying particular attention to whether the connectors are loose or detached, and whether the wire connections are correct.
5. After the maintenance is completed, it should be verified whether the fault has been eliminated.
6. If the fault code cannot be retrieved or the fault content cannot be found after retrieval, the fault range can be roughly determined based on the fault phenomenon, and the method of checking the working performance of each component one by one can be used to eliminate it.
3¡¢ Diagnosis of common faults
1. The engine cannot start or has difficulty starting
(1) The starter does not rotate or rotates slowly a) Check the battery voltage. b) Check if the battery terminals, wire connections, etc. are loose. c) Check the starting system, including the ignition switch, start switch, neutral start switch, and starter motor, and ensure that all wiring connections are loose.
(2) The starter motor rotates normally, but the engine cannot start. a) Retrieve the fault code. b) Check the working condition of the fuel pump. c) Check if the idle system is working properly (if the idle system is not working properly, the engine can start when the accelerator pedal is pressed). d) Check the ignition system, including high-voltage spark, ignition timing, spark plugs, etc. e) Check for air leaks in the intake system. f) Check if the air flow meter or air pressure sensor is not functioning properly. g) Check if the fuel injector and low-temperature start fuel injector are working properly. h) Check the EFI system circuit, including the relevant terminals of the ECU connector. i) Check for any malfunctions in the mechanical components.
2. Poor engine idle speed
1) Retrieve the fault code and analyze the cause of the fault. 2) Check for air leaks in the intake system.
3) Check the operation of the PCV valve on the crankcase ventilation pipe (the PCV valve should be closed at idle).
4) Check if the idle adjustment screw on the throttle valve is adjusted correctly. If the adjustment screw is not adjusted correctly, it will cause the mixture to be too lean during idle, resulting in unstable engine idle.
5) Check the ignition timing.
6) Check the injection condition of the fuel injector.
7) Check the operation of EFI system circuits and components.
8) Check the condition of the mechanical system.
3. Idle speed too high
1) Check if the throttle valve is stuck and cannot be closed.
2) Check if the cold start injector is continuing to inject fuel.
3) Check if the throttle position sensor outputs an incorrect voltage.
4) Check if the fuel injection pressure is too high.
5) Check if the vacuum sensor hose of the pressure regulator is detached or broken.
6) Check if the idle control system and VSV valve are working properly.
7) Check the fuel injector for fuel injection and leakage.
8) Retrieve the fault code and determine the cause of the malfunction.
9) Regarding the operation of EFI system circuits and components.
10) Check if the ignition timing is incorrect.
4. Unstable engine speed
1) Retrieve the fault code and analyze the cause of the fault.
2) Check for air leaks in the intake system.
3) Check the fuel supply of the fuel pump and whether the pressure in the fuel pipeline is normal.
4) Check if the fuel pressure regulator is not working properly.
5) Check the injection condition of the fuel injectors to see if any individual injectors are not working or if the injection quantity is inaccurate.
6) Check the ignition system, such as ignition timing, high-voltage spark condition, spark plug carbon buildup, etc.
7) Check if the air filter element is clogged.
8) Check if the gasoline filter element is clogged.
9) Regarding the operation of EFI system circuits and components.
10) Check the mechanical parts, such as cylinder pressure, valve clearance, etc.
5. The phenomenon of engine backfire is mostly caused by the mixture being too lean or the ignition time being too late.
1) Retrieve the fault code and analyze the cause of the fault.
2) Check for air leaks in the intake pipe.
3) Check if the output signal of the throttle position sensor is correct.
4) Check the ignition timing.
5) Check if the fuel pressure is too low.
6) Check if the fuel injector injection time is too short.
7) Check if the fuel injector is stuck or blocked.
8) Check the working condition of EFI system circuits and components, mainly including various related sensors such as oxygen sensor, water temperature sensor, intake temperature sensor, intake pipe pressure sensor, etc.
6. The phenomenon of exhaust pipe blasting is mainly caused by incomplete combustion factors such as excessive mixture, some cylinders not working, and incorrect combustion time.
1) Retrieve the fault code and analyze the cause of the fault.
2) Check the ignition timing to see if the ignition time is too late.
3) Check if the cold start fuel injector is still spraying or leaking, and further identify the cause.
4) Low temperature start injector timing switch failure.
5) Individual cylinder spark plugs do not ignite or the spark is too weak.
6) Check the fuel injector for excessive fuel injection or individual cylinders with excessive fuel injection, and for any dripping.
7) Check if the fuel pressure is too high, if the pressure regulator is malfunctioning and causing the return line to fail to open, and if the vacuum sensor hose of the pressure regulator is detached or broken.
8) Check if the output signals of the air flow meter sensor and throttle position sensor are correct.
9) Check the operation of EFI circuit and related sensors.
7. Poor engine acceleration
1) Check if there is any air leakage in the intake pipe.
2) Check if the ignition time is too late.
3) Retrieve the fault code and analyze the cause of the fault.
4) Check the fuel injection system, such as fuel pressure and injector operation.
5) Check whether the ignition system, especially the knock sensor and igniter, are working properly.
6) Check if the throttle position sensor is functioning properly.
7) Check the operation of EFI circuits and components related to fuel injection.
8) Check cylinder pressure, valve clearance, spark plug operation, and valve timing.
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