The third diesel vehicle can't afford to add the throttle when downshifting.

It may be the diesel filter element, the oil-water separator, or the solenoid valve on the large pump, indicating that the engine is faulty.

The reason why the diesel engine can't add the throttle is that one of the throttle position sensor and the intake pressure sensor is faulty. Throttle position sensor and intake pressure sensor are important sensors for detecting engine load. If there is a fault, the computer can use the substitute value to keep the engine working, but the working condition is worse, and the fault varies according to the degree of damage.

The working principle of diesel engine is somewhat different from that of gasoline engine. A four-stroke gasoline engine has a power stroke. At the end of the compression stroke, the spark plug will ignite the combustible mixture in the combustion chamber, so that the combustible mixture will burn, and the burnt combustible mixture can push the piston to move downward, so that the engine can do work.