The reason why excavators detain cars is:

The engine power does not match the hydraulic pump power.

Insufficient engine intake.

Braking caused by heavy objects.

The hydraulic pump or distribution valve leaks, causing the pump power to exceed the engine power.

Reasons such as regulator wear, excessive pressure and flow of pump valve group, and wear of internal components of the pump.

Poor diesel signal, possibly due to cold weather and high diesel viscosity, resulting in insufficient fuel supply.

The voltage value of the PRV solenoid valve is insufficient.

The engine valve clearance is too large or too small.

The pump pressure is incorrect.

Insufficient motor speed or load power.