14 1.4 manual gear Bora shakes when flameout.

The reason of carbon deposition is the cold start, flameout or jitter of the car. Carbon deposition generally appears on the inner wall of throttle valve, intake valve head, intake port, piston top and combustion chamber. Excessive carbon deposition will lead to insufficient air intake, difficult starting or easy flameout at idle speed. After the water temperature reaches the normal working temperature of the engine, the computer repeatedly adjusts the position of the throttle valve plate, causing the idle speed to rise and fall.

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.