How to distinguish whether the NTC temperature control switch of gasoline engine is faulty

　　Common faults and troubleshooting methods of automobile engine

　　When the car engine does not work 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 of the fault and the location where the fault occurs. The author now summarizes the common faults of automobile engines as follows:

　　1.1 The engine does not start

　　(1) Failure phenomenon: Turn on the ignition switch, turn the ignition switch to the start position, and the engine will not start.

　　(2) Possible reasons for the failure:

　　A. The failure of the starting system makes the engine unable to rotate or rotate too slowly: ①The battery is insufficiently stored, the electrode pile clamp is loose or the electrode pile is seriously oxidized; ②The main circuit fuse is broken; ③The ignition switch is faulty; ④The starter is faulty; ⑤Starting Open circuit or poor contact in the line connector.

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

　　C. Failure of the fuel injection system: 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; too dirty.

　　D. Intake system failure: ① The idle speed control valve or its control circuit is faulty; ② The air pipe of the idle speed control valve is broken or the joint leaks; ③ The air flow meter is faulty.

　　E.ECU failure.

　　(3) Diagnosis and exclusion methods and steps.

　　① When the starting gear is turned on, the starter and the engine cannot be rotated, and the inspection should be carried out according to the failure of the starting system. First, check the battery storage condition and the pole connection and contact; if the battery is normal, check the starting circuit, fuse and ignition switch;

　　② Step on the accelerator to the medium opening position, and then start the starter. If the engine can be started at this time, it means that the fault is the idle speed control valve and its circuit fault or the air leakage of the intake pipe. If the engine still does not start when the accelerator is pressed to the medium opening position, the next step should be checked.

　　; ③ Carry out visual inspection. Check the intake pipeline for air leakage; check whether the hoses and their connections are in good condition; check the crankcase ventilation device hose for air leakage or rupture;

　　④ Check the high pressure 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 after confirming that there are tears in the fuel tank;

　　⑦ Check the ignition timing and the ignition sequence of each cylinder;

　　⑧ Check the working condition of the fuel pump switch installed on the air flow meter;

　　⑨ Check the working conditions of the spark plugs of each cylinder;

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