What should I do if the BMW 5 Series cold car starts to shift gears and stall?

The most common reason for the shaking and flameout of the BMW 5 Series cold car in Pacific Auto Network is carbon deposition, which usually appears in the inner wall of throttle valve, intake head, intake port, piston top and combustion chamber. It is necessary for the owner to go to the repair shop to find out the specific reasons and solve them as soon as possible so as not to affect the use of the vehicle.

Excessive carbon deposition on the inner wall of the throttle will cause insufficient air intake, difficult starting or easy flameout at idle speed. After the water temperature reaches the normal working temperature of the engine, the idle speed rises and falls due to the excessive opening of the throttle valve exceeding the normal idle speed value, and the computer repeatedly adjusts the position of the throttle valve plate.

The surface of carbon deposit is loose, similar to sponge. 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, it will be more difficult to start a cold engine if carbon deposits accumulate too much at the head of the intake valve and the valve is not closed tightly. Even if it can be barely started, it will be closed soon.

The overall dimensions of BMW5 Series are 5047 *1860 *1491(mm), and the wheelbase is 2888 mm The new 5 Series is 66 mm longer than the previous generation. The power system of BMW5 series has been further strengthened. The top version 545i is equipped with a 7-series V8 engine, with a maximum power of 245kW/333HP (6 100rpm), a maximum torque of 450 Nm (3600rpm), a maximum speed of 250km/h and an acceleration of 5.9 seconds from 0- 100km.

(Photo/Text/Photo: Pacific Auto Network Q&A called Beast)