What if the Jetta train is heavy in winter?

There are the following possibilities: carbon deposition in the intake valve and throttle valve will cause insufficient cylinder pressure and make it difficult for the vehicle to start cold; When carbon deposits are attached to the intake valve and throttle valve, the engine cannot accurately control the amount of gasoline and air sent into the combustion chamber, resulting in unstable idle speed of the engine. The blockage of fuel nozzle caused by carbon deposit will affect the fuel injection quantity, and the mixture will not reach the ignition ratio, which will also make it difficult for the vehicle to start cold. In addition, if the water temperature sensor fails, it will cause the sensor to be unable to obtain an accurate temperature signal (both when the cold car starts and when the hot car starts), so that the ecu can't accurately adjust the mixture concentration according to the water temperature signal (the ecu can't get the signal to provide an excessively rich mixture, but can only supply a dilute mixture to the engine), which makes it difficult to start the cold car. It is recommended that you go to the 4s shop for corresponding maintenance in time (clean up the carbon deposit at the intake valve, throttle valve and fuel nozzle, the water temperature sensor needs to be replaced due to failure, the car can't start, the idle speed is unstable, the speed is high and low, and the oil supply is abnormal). Check items are as follows: 1, vehicle battery voltage is low; Specific detection method: test the battery voltage with a voltage range of three meters. If it is lower than 10V, it is recommended to replace it. If it is around 1 1V, it is barely used; Be prepared to be replaced. 12V or more; 2. Check whether it is caused by carbon deposition; If driving about 20,000 KM, check and clean the throttle; 3. Check, test and replace the spark plug; 4. Confirm the oil quality of the added gasoline; 5. Check the ignition switch; 6. Test and check the starter, gasoline pump, sensor and other related parts of the starting and oil supply system; 7. Don't start it immediately after being electrified again, wait for 30 seconds to 1 minute, and then ignite; See if it works; In any of the above cases, please note that when you can't get a taxi at one time, you must call it again every 15-30 seconds to protect the battery from excessive power generation and prolong its service life.