What is the cause of smoke from the small hole on the throttle of diesel engine?

The reason why the diesel engine can't add the throttle;

In the D-type electronic control system, throttle position sensor and intake pressure sensor are important sensors for detecting engine load. If one of them fails, the computer can use the substitute value to keep the engine working, but the working condition is worse, and the failure varies according to the degree of damage. The throttle position transmitter is damaged, the refueling fails, and the car will fall down at a constant speed.

In Bosch M 154 electronic control system, the computer adjusts the steps of idle motor according to the load to keep the normal engine speed. If there are signals such as virtual wiring, out-of-control idle motor or internal abnormality during work, the computer will control the engine speed. At this time, the engine speed will be limited to a certain speed, but there is no fault code at this time, and the idle speed is generally abnormal.