Analysis of starting fault of electronic injection vehicle:

The engine of long axis single-phase motor products can start normally must have three factors: compression, spark and mixture. If a certain element works abnormally, it will cause the engine can not start or difficult to start. There are many factors leading to the start failure of EFI engine. The failures analyzed below are all occurred under the conditions of battery voltage, normal operation of starting system, good compression and spark of engine, and normal operation of exhaust purification device.

The starting fault usually shows that it is difficult to start and start, and the starting difficulty can be divided into cold start difficulty and hot start difficulty.

1、 Cannot start

The engine can not start and has no sign of ignition, which is generally caused by no fuel injection. The main reasons are as follows:

1. Speed signal system fault

The engine speed and crankshaft position sensor detects the speed signal and provides the crankshaft position signal when the engine is working, which is the main basis and basis of the control system. If the sensor or its circuit fails, the ECU can't receive the speed signal and crankshaft position signal, it can't control the fuel injection and ignition timing correctly, and there will be the phenomenon that the fuel injector doesn't work and the spark plug doesn't jump. Check with stethoscope and timing light to confirm whether the fuel injector and spark plug are working.

In case of the above fault, the general self diagnosis system can display the fault code, so the speed sensor, No. 1 and No. 2 camshaft position sensor and their circuits should be checked comprehensively. First, disconnect the connector of each sensor and check their resistance. If the resistance is abnormal, replace it; If it is normal, check whether the wiring and connector between ECU and sensors are normal.

2. Fuel pump and control circuit fault

If the fuel pump or control circuit fails, there will also be no fuel pressure in the fuel supply system. Even if the injector works normally, the fuel can not be injected normally. The inspection method is: connect diagnostic plug terminal + B and FP with short wiring, then turn on the ignition switch (do not start), and check whether there is pressure in the oil inlet hose. If there is pressure in the hose and the sound of oil return can be heard, there is no problem with the fuel pump itself; Otherwise, the fuel pump should be checked, and the resistance between terminals 4 and 5 can be measured with a multimeter. If it does not meet the requirements, the fuel pump should be replaced. If the fuel pump works normally, check its control circuit, including fuse, EFI main relay, fuel pump relay, resistor, wiring and connector.