What’s Wrong With The Engine If It Can Not Be Started

Sometimes we will encounter vehicle engine can not start the problem, extreme cases, if it happens to be we can not go to the repair point maintenance repair, how to do? We next understand the car engine can not start what may be the cause of the problem, as well as the solution to the problem.

The reasons that the engine can not start might be:

1. Starting system failure so that the engine can not turn or turn too slow to cause the engine can not be started

① insufficient battery storage, loose electrode post clamps or electrode post oxidation; ② circuit fuse broken; ③ ignition switch failure; ④ starter motor failure; ⑤ start line break or poor contact with the line connector

2. Engine fails to start due to faulty ignition system.

Faulty ignition coil, resulting in weak or no high-voltage spark; faulty ignition coil; faulty spark plug.

3. Engine fails to start due to fuel injection system failure.

No fuel in the fuel tank; ② Fuel pump does not work or pump pressure is too low; ③ Fuel pipe leakage; ④ Disconnected relay; ⑤ Fuel pressure regulator does not work well; ⑥ Fuel filter is too dirty.

4. Air intake system problems

Failure of the idle control valve or its control circuit; ② cracked air hose or leakage of the idle control valve; ③ failure of the air flow meter; ④ failure of the throttle.

5. Sensor failure

① Crankshaft position sensor

◆ Loss or abnormality of crankshaft position signal Although the engine can be started, it will cause confusion in the calculation of the ECU due to the absence of basic signal, and the injection advance angle, rail pressure signal, and correction data will be irregularly incorrect. Therefore, the crankshaft position sensor is a necessary component to be tested when irregular changes in data flow are detected during maintenance testing.

◆ ECU correction of the amount of fuel injected into each cylinder is crankshaft position sensor according to the waveform generated by the signal hole in the flywheel to detect the operating speed of the piston in each cylinder to determine the signal abnormalities will lead to abnormal correction of the amount of fuel injected, triggered by the engine in the middle and low-speed shaking and other phenomena.

② camshaft position sensor camshaft position sensor is also the basis of the ECU computing signal, this signal is lost or abnormal can cause engine startup difficulties.

③ Water Temperature Sensor Abnormal signals from the water temperature sensor can cause the following effects on the engine operating conditions:

◆ The low-temperature signal can make the ECU think of cold start thickening conditions, increase the fuel injection, resulting in too rich a mixture, the engine combustion is incomplete, the power to reduce the situation;

◆ The high temperature signal can make ECU think that the engine is already high temperature, limit the oil, reduce the engine speed.

④ Oil pressure sensor oil pressure sensor signal abnormality (low voltage value) can make ECU think that the oil pressure is not enough, limit the oil, reduce the engine speed.

⑤ Intake Pressure Sensor The intake pressure sensor is an important basis for ECU to calculate the size of fuel injection. Signal abnormality: high voltage value signal, can make the ECU that in order to ensure the mixing ratio, increase the amount of fuel injection, resulting in engine powerlessness, black smoke, when more than the limit of the ECU suddenly cut off the power to stop the oil; low voltage value signal, can make the ECU to reduce the amount of fuel injection, engine powerless.

The engine can not start several situations and solutions

1. If the start switch is turned to the S position, the engine does not respond to check the start circuit, fuse, relay, battery and wiring, start switch. For automatic transmission cars, should check whether the shift handle in the P / N position.
2. If the starter switch is turned to the S position, only the starter motor can be heard to make a "clicking" sound, and the engine still does not rotate.

Check the battery voltage and wiring.

Check the battery voltage and wiring ② check the starter suction and pull coil and keep the coil operating conditions

③ Check whether the engine crankshaft locking

3. Only the starter motor idles, the engine does not rotate Check the operation of the starter motor's suction and retention coils, and check the starter motor pinion and one-way clutch. 4.
4. if start switch is turned to S position, engine speed is weak and will not start (200r/min) check battery, starter.
5. if the engine starts when the starter switch is turned to position S, but the engine stalls when the ignition switch is released and returned to the ON position the starter switch does not work well.
6. If the starter motor drives the engine very strongly (more than 200r/min), but the engine still does not start

① Check the fault code with an instrument or self-diagnostic system.

② Check the ignition circuit.

Check the ignition circuit.

◆ Pull out the spark plug high-pressure wire or the central high-pressure wire, and let it test fire at 5-8mm from the hitch. If there is no fire, first check: engine speed sensor, crankshaft position/camshaft position sensor signal output and wiring conditions

③ check the oil supply system to check the spark plug wetting situation, wetting is that the oil supply circuit; if not wetting If not wetting then check the following items：

◆ Gasoline pump working condition, energized, oil pressure

◆ Injector circuit and working condition

◆ Whether the oil circuit is smooth, whether there is oil in the fuel tank.

Please remember safety precautions while working on a vehicle, especially around electrical components and fuel systems. In case you're unable to diagnose or fix the problem, it's best to seek professional assistance from a mechanic.