Skoda Haorui engine fault light is on, what should I do?

When the automobile engine is not working normally, but the self-diagnosis system has no fault code output, it is especially necessary to rely on the inspection and judgment of the operator to determine the nature and location of the fault. The author summarizes the common faults of automobile engines as follows:

1. 1 Engine failed to start.

(1) Symptoms: Turn on the ignition switch and turn it to the start position, but the engine will not start.

(2) Possible causes of failure:

A. The engine can't rotate or rotates too slowly due to the failure of the starting system: ① the battery power is insufficient, the pole clamp is loose or the pole is seriously oxidized; ② The main fuse of the circuit is blown; (3) ignition switch failure; ④ Starter failure; ⑤ The starting line is open or the line connector is in poor contact.

B. Ignition system failure: ① The ignition coil is not working well, resulting in weak or no high-voltage spark; ② Igniter failure; ③ The ignition time is incorrect.

C. Fuel injection system failure: ① There is no fuel in the fuel tank; ② The fuel pump does not work or the pump oil pressure is too low; (3) The fuel pipe leaks and deforms; (4) the circuit breaker relay is disconnected; ⑤ The fuel pressure regulator is not working properly; ⑥ The fuel filter is too dirty.

D failure of air intake system: ① failure of idle speed control valve or its control circuit; ② The air pipe of idle speed control valve is broken or the connector leaks; ③ The air flowmeter is faulty.

E.ECU failure.

(3) Methods and steps of diagnosis and elimination.

① When the starting gear is set, neither the starter nor the engine can rotate, so it should be checked according to the fault of the starting system. First, check the storage of the battery and the connection and contact of the pole; If the battery is normal, check the starting circuit, fuse and ignition switch; ② Step on the accelerator to the middle open position, and then start the starter. If the engine can still be started at this time, the fault is idle control valve and its circuit fault or air leakage in the intake pipe. If you step on the gas pedal to the middle open position, the engine still can't start, so check the next step. ③ Conduct visual inspection. Check whether the air inlet pipe leaks; Check whether the hose and its joint are in good condition; Check whether the crankcase ventilation hose leaks or breaks; ④ Check the high voltage spark. If the high-voltage spark is abnormal, check the high-voltage line, ignition coil, distributor and electronic igniter; ⑤ Check whether the ignition sequence is correct; ⑥ Check the oil supply of the oil supply system. Check the fuel supply pressure in the fuel pipe when it is confirmed that the fuel tank is torn; ⑦ Check the ignition timing and ignition sequence of each cylinder; ⑧ Check the working condition of the fuel pump switch installed on the air flowmeter; Pet-name ruby check the working condition of each cylinder spark plug; Attending to check the ignition timing. If the ignition timing is incorrect, further check the ignition timing control system; ? B 1 1？ Check the power supply and working condition of ECU to determine whether it is a fault of ECU.

1.2 engine stall fault

(1) fault phenomenon: when the engine is working, the speed rises and falls, which is called engine stall phenomenon, and its fault is called engine stall fault.

(2) Cause of failure: The reasons for the high and low engine speed include fuel nozzle system failure, ignition control system failure and air intake system failure. Common reasons for failure are as follows:

① Air leakage in the air intake system. For example, leakage of hoses and connectors, leakage of PVC valves, leakage of EGR system, leakage of dipstick socket and leakage of oil filter cover. ② The air filter element is too dirty; ③ The air flow meter is not working properly; ④ The supply pressure of the fuel injection system is unstable. Such as tubing deformation, poor connection and contact of system lines, insufficient pump pressure of fuel pump, unstable operation of fuel pressure regulator, dirty fuel filter, jitter of relay contact of circuit breaker, etc. ⑤ The ignition timing is incorrect; ⑥ The cold start injector and temperature timing switch are not working properly; ⑦ECU failure.

(3) Diagnosis and elimination methods and steps: ① Check whether the air inlet pipe leaks. Check all hoses and connectors, PVC valve pipes, EGR system, dipstick socket and oil filter cover; ② Check the oil supply pressure. Check whether there is too little fuel in the fuel tank and the pressure in the fuel pipe is unstable. The specific method is the same as when checking that the engine cannot be started; ③ Check whether the air filter element is too dirty; ④ Check the ignition advance angle; ⑤ Check the working conditions of spark plugs in each cylinder; ⑥ Check the working conditions of cold start injector and temperature time control switch; ⑦ Check the output voltage of air flow meter and its relationship with engine working conditions; ⑧ Check the fuel injection quantity of the fuel injector; Pet-name ruby check the working condition of ECU.

1.3 engine idling fault

(1) symptom: the engine works normally when it runs above the medium speed. When the vehicle speed is at or near the idle speed, the phenomenon of unstable idle speed or even flameout occurs, which is called poor idle speed fault.

(2) Cause of failure: Poor idle speed is usually caused by intake system and fuel injection control system, and occasionally caused by engine mechanical failure. The common causes of poor idle speed are: ① air leakage in the intake system; ② The cold start injector and temperature time control switch are not working properly; ③ Abnormal oil supply pressure of fuel injection system; (4) Nozzle failure leads to poor atomization quality; ⑤ECU failure.

(3) Diagnosis and elimination methods and steps: ① Check whether the air inlet pipe, PVC valve hose and dipstick are leaking; ② Check whether the air filter element is too dirty; ③ Check whether the cold start fuel injector and temperature time control switch are normal; ④ Check whether the fuel system pressure is too low; ⑤ Check the injection of the fuel injector; ⑥ Check cylinder pressure and valve clearance when necessary; ⑦ Check ECU.

1.4 mixture is too lean.

(1) fault phenomenon: the engine speed is unstable, the power is obviously insufficient, and there is backfire. It can be considered that the engine has a fault of too lean mixture.

(2) Cause of failure: ① Air leakage in the air intake system; (2) cold start injector and temperature timing switch failure; ③ The system fuel pressure is too low; ④ The fuel injector is stuck or blocked; (5) air flowmeter failure; ⑥ Water temperature sensor failure; ⑦ Fault of throttle position sensor; ⑧ECU failure.

(3) Diagnosis and elimination methods and steps: ① Check whether the air intake system leaks; ② Check the timing switch of cold start injector; (3) Check whether the fuel injector is blocked; ④ Check the working condition of the air flow meter; ⑤ Check the water temperature sensor; ⑥ Check the operation of the throttle position sensor; ⑦ Check the input and output signals of each terminal of ECU.

1.5 Accelerated failure

(1) Fault phenomenon: When the throttle is slowly accelerated from low speed to high speed, the engine works completely normally, but when it is rapidly accelerated, the engine speed changes slowly, and sometimes there is panting or backfire.

(2) Cause of failure: ① Air leakage in the air intake system; ② The system oil supply pressure is too low; ③ The ignition voltage is too low; ④ The ignition time is too late; ⑤ Cylinder pressure is too low or valve clearance is too small; ⑥ The throttle position sensor is not working properly; ⑦ECU failure.

(3) Diagnosis and elimination methods and steps: ① Check whether the air intake system leaks; (2) check the high voltage spark; ③ Check whether the ignition advance angle is normal; ④ Check the system oil supply pressure; ⑤ Check whether the throttle sensor works normally; ⑥ Check whether the signals of each terminal of ECU are normal; ⑦ Check the valve clearance and cylinder working pressure when necessary.

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