What is the reason why the hot car does not start well?

At high temperature, carbon deposit has a strong adsorption effect on gasoline. If the intake valve, throttle valve, piston and other carbon deposits are more. , easy to absorb part of the fuel, resulting in too thin mixture, which affects the start-up.

2. Water temperature sensor

The water temperature sensor can correct the fuel injection pulse width. If it doesn't work well and can't provide the correct temperature signal, it will affect the fuel injection of the engine, which will easily lead to abnormal air-fuel ratio of the mixture and affect the start-up.

3. Air temperature sensor

Similar to the water temperature sensor, the air temperature sensor is also used to correct the fuel injection quantity. The higher the temperature of the air temperature sensor, the thicker the mixed steam will be, or the air temperature sensor will be too dilute due to open circuit or poor grounding. But too thick and too thin will be difficult to start.

4. Fuel quality issues

After the hot car is turned off, the temperature in the engine compartment is still very high. If the fuel quality itself is easy to volatilize, it is easy to form a higher evaporation pressure in the fuel rail. When this pressure is greater than the pressure of the oil supply system, air resistance will be formed, which will cause the oil vapor sprayed by the oil nozzle to be too thin and difficult to start.

5. The choke falls off

Fuel nozzle leaks. Because the engine has just turned off and the temperature is still high, the leaked fuel will turn into oil and gas and enter the intake pipe. At this time, the hot start will cause the mixture to be too rich and the start will be difficult.

Can test valve assembly, coolant temperature sensor, spark plug, crankshaft position sensor, oil pump, etc. , which may make it difficult to start. It is recommended that you use a diagnostic computer to test and narrow down the fault range.

Extended data:

? In most people's minds, it is always believed that when you want to use the car early in the morning (or when you don't use it for a long time), you should idle to warm up and wait for three to five minutes before you go on the road, which is most beneficial to the car.

But in fact? Are you sure this is the right way to warm up the car? According to a statistic, more than 90% engine parts are worn within three minutes after the cold car starts.

The correct way to warm up the car should be to go on the road 30 seconds after starting to 1 minute. But don't drive at high speed at this time, keep low speed, and the engine speed should not exceed 3000~3500 rpm. Generally keep 2000 rpm. Otherwise, the severe wear and tear suffered by the engine and gearbox is irreparable. After the engine temperature rises to the normal working temperature, the "personal habit" driving mode can be restored.

References:

Baidu Encyclopedia _ Hot Car