104749-0090 ZEXEL INJECTION-PUMP ASSEMBLY Cross 1047490090 s20113800c

Illustration 1 g00564916The test for the engine oil pressure switch is a test for the actuation of the engine oil pressure and a test for the electrical continuity. This test will determine if the engine oil pressure switch is faulty and if the engine oil pressure switch needs to be replaced. Use the 1U-5470 Engine Pressure Group and the 8T-0500 Continuity Tester for this test.
If an access hole that has the same engine oil pressure as the engine oil pressure switch is not close to the engine oil pressure switch, remove the engine oil pressure switch. Install a tee at this location. Install the engine oil pressure switch on one side of the tee, and connect the 1U-5470 Engine Pressure Group on the opposite side of the tee. Note: This test can also be performed on a bench with air pressure if the correct fittings are available.
Disconnect the connector for the engine oil pressure switch from the junction box. While the engine is stopped, check the continuity between contact (2) and common contact (1). The continuity should be open. Next, check the continuity between contact (3) and common contact (1). This continuity should be closed.
Start the engine and allow the engine to run. Observe the 8T-0500 Continuity Tester and the 1U-5470 Engine Pressure Group from the time that the engine is started until the engine is running. The continuity between contact (2) and common contact (1) should close when the engine oil pressure is greater than the deactuation pressure of the engine oil pressure switch. The engine should begin to run and the starting motor should disengage when the engine oil pressure is above the deactuation pressure of the engine oil pressure switch. Record the reading from the pressure gauge when the continuity of the engine oil pressure switch changes. Compare the reading with the specifications for the deactuation pressure of the engine oil pressure switch.
The engine oil pressure switch should close across contact (2) and common contact (1) when the engine oil pressure is above the specified deactuation pressure of the engine oil pressure switch. If the engine oil pressure switch does not close the engine oil pressure switch is faulty. Replace the faulty switch.