What is the reason why it is difficult to start a cold car?

The above two problems will lead to the phenomenon that the engine is difficult to start cold.

The reasons for the deterioration of low-temperature starting conditions are: high viscosity of engine oil reduces the starting speed, low temperature reduces the ion concentration of the battery, reduces the ignition energy, and low temperature reduces the molecular activity, making it difficult to form combustible gas mixture. Therefore, it is difficult to start at low temperature, and too much carbon deposit will easily lead to the blockage of idle air duct, which will lead to poor air intake and difficult start of cold car. Cause and solution:

First, check whether there is too much carbon deposit at the throttle valve and idle valve. You can step on the clutch before ignition, so if there is too much carbon deposit, you need to clean it first, and then check whether the water temperature sensor of the engine control system works properly.