The first reason why the oil pump doesn't work is the circuit fault. Circuit faults include: fuse blown, high-voltage coil disconnected, low-voltage circuit disconnected, central ignition wire falling off, ignition head leaking, spark plug damaged, which will lead to no sound.
Hydraulic oil pump is an energy conversion device, which works under the drive of driving motor (or engine) to realize the energy conversion from mechanical energy to hydraulic oil pressure energy, thus promoting the working mechanism of truck crane. The hydraulic pumps used in hydraulic transmission work by changing the sealed working volume, so they are all positive displacement pumps.