Why does the oil pump motor and oil pump start, but there is no pressure?

There are several characteristics of the situation described where the motor has not developed any pressure, but it is still running. A systematic approach is necessary to understand and troubleshoot these problems. Below is a detailed breakdown based on the problem overview:

1.System Blockage:

• System blockage can prevent oil from circulating in hydraulic system, leading to no pressure build-up. Check for clogs or obstructions in lines, valves or filters.

2.Air entrainment:

• A pump that loses prime because of air entrainment will fail to produce pressure as well. To maintain pressure levels, it is important to ensure that the system is properly bled and free from air.

3.Wear in Pump:

• Inspection may reveal that the pump has worn out making it difficult for it to generate enough pressure needed. This calls for checking wear on the pump especially gears/vanes and replacing if necessary.

4.Sealing Problems:

• Leakages resulting from poor sealing prevent pressures from building up.. Examine all seals, gaskets and fittings within the system making sure they are adequately seated and intact.

5.Relief Valve Settings:

• Inappropriate adjustment of this relief valve might let oil bypass hence no pressure builds up. Confirm if it’s set right then adjust as per your systems specification

6.Low Oil Level:

• Also absence of enough oil may result into low pressures. Confirm whether your oil system has adequate volume at its disposal for correct functioning.

7.Mechanical faults:

• This means lack of applied physical force that can be caused by breaking or jamming gears including problematic motor and bearing damages within a pumping device or components supporting its operation

8.Electrical Faults:

• The poor electric contacts between engine parts may also lead to inability of power being adequately delivered into pumps thus stopping them from creating required rotational rates capable of developing desirable amounts of force.

9.Wrong Pump Rotation;

• Make sure that your pump turns in the proper course; otherwise you won’t get any pressure

10.Hydraulic Fluid Quality;

• Quality of hydraulic fluid affects the pressure in your system. Cleanliness, type, and viscosity of hydraulic fluid required for your system should be observed.

11.System Design Issues:

• In some cases, hydraulics had design faults that prevent it from building up any pressure. It might be good to consult a hydraulic systems expert for reviewing the system’s design.

In short, investigating why an oil pump does not generate pressure requires following a systematic approach when addressing potential problems such as clogging or blockage, pump wear and tear, air entrainment, sealing difficulties and other similar mechanical or electrical failures. It may also be helpful to refer to experts or review the maintenance manual of the system for detailed troubleshooting steps and possible corrective measures.