Volkswagen ea2 1 1 cold car start and stop.

The reason for the start-up jitter and flameout of the cold car may be serious carbon deposition, which generally appears in the inner wall of the throttle valve, the head of the intake valve, the inner wall of the intake port, the top of the piston and the inner wall of the combustion chamber. Excessive carbon deposition on the inner wall of the throttle will cause insufficient air intake, difficult starting or easy flameout at idle speed.

In fact, it is not only the throttle valve that is the easiest to deposit carbon, but also the head of the intake valve (the end of the intake port). The gasoline injection of indirect injection engine is injected into the intake space where the intake valve head is located, and gum, wax and unburned carbon compounds are deposited in this part. The surface of carbon deposit is loose and porous. After stopping for a night or a long time, when the cold car is started, most of the fuel injected by the injector is absorbed by carbon deposits.

The amount of fuel entering the cylinder is insufficient, and the mixture is thin and difficult to ignite. The motor is running, and the fuel entering the cylinder is enough to ignite after multiple injections. In this case, it will definitely be difficult to start. What's more, if there is too much carbon in the head of the intake valve, the valve will not be closed tightly, which will make the cold start more difficult. Even if it can be barely started, it will be closed soon. Moreover, with the increase of engine temperature, the fuel in the carbon deposit evaporates and is sucked into the cylinder to participate in combustion. This part of the fuel is out of control, resulting in too much mixture and poor engine work.