3500B Industrial Engines Caterpillar

The Engine's Prelubrication System may increase the life of certain engine parts. When the Start/Run/Stop switch is turned to the Start position, the motor of the engine prelubrication system will start. The engine's prelube motor will run until the engine prelube pressure switch closes. A set of contacts on the prelube control relay sends a signal to the ECM in order to start the engine.

The Electronic Technician(ET) will allow a user to monitor the status of certain engine functions. The ET enables the operator to view the status of the Prelubrication System. The engine should start when the ET indicates a "COMPLETED" status for the prelubrication system.

Illustration 1	g00745818

Test Step 1. Check the Electrical Connectors and the Wiring.

1. Turn the Battery switch for the ECM to the OFF position.

2. Turn the breaker at the battery to the OFF position.

3. Thoroughly inspect the ECM connector J1/P1. Inspect all of the other connectors. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.

4. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

5. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

6. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

7. Check the harness and the wiring for abrasion and pinch points.

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring should be free of corrosion, abrasion or pinch points.

Results:

• OK - The wiring and connectors are okay. Proceed to Test Step 2.

• Not OK - Repair the wiring and connectors or replace the wiring or the connectors. Ensure that all of the seals are properly connected. Verify that the repair eliminates the problem.STOP

Test Step 2. Check the Engine Prelube Pressure Switch.

1. Disconnect the wires from terminals 1 and 2 of the engine prelube pressure switch.

2. Measure the resistance between terminals 1 and 2 of the engine prelube pressure switch .

3. Replace all wires.

Expected Result:

The resistance should be greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. The engine prelube pressure switch is not active. Proceed to test step 3.

• Not OK - The resistance is less than 20,000 Ohms. The engine prelube pressure switch is active. Verify that the engine does not have a residual oil pressure that is high enough to activate the switch. If there is no residual oil pressure the switch is not operating correctly.

  Repair: Replace the engine prelube pressure switch. Verify that the problem has been solved.

  STOP

Test Step 3. Check the Voltage to the Prelube Relay.

1. Turn the breaker at the battery to the ON position.

2. Turn the Battery switch for the ECM to the ON position.

3. Connect a voltage test lamp between terminal 3 of the prelube relay and the engine ground.

4. Turn the Start/Run/Stop switch to the RUN position.

5. Monitor the voltage test lamp for illumination.

6. Turn the Start/Run/Stop switch to the STOP position.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminated. Proceed to test step 4.

• Not OK - The voltage test lamp did not illuminate. Proceed to test step 7.

Test Step 4. Check the Voltage to the Prelube Motor.

1. Connect a voltage test lamp between terminal 1 of the prelube relay and the engine ground.

2. Turn the Start/Run/Stop switch to the RUN position.

3. Monitor the voltage test lamp for illumination.

4. Turn the Start/Run/Stop switch to the STOP position.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminated.

  Repair: Check the voltage at the prelube motor. If the voltage is present at the prelube motor, the prelube motor should run. If the prelube motor does not run repair the prelube motor or replace the prelube motor. If the voltage is not present at the prelube motor there is a problem in the wiring and/or the connectors between the prelube relay and the prelube motor. Repair the connectors or wiring and/or replace the connectors and/or wiring.

  STOP

• Not OK - The voltage test lamp did not illuminate. Proceed to test step 5.

Test Step 5. Check the Voltage to the Contacts on the Prelube Relay.

1. Connect a voltage test lamp between terminal 2 on the prelube relay and the engine ground .

2. Monitor the voltage test lamp for illumination.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminated. Proceed to test step 6.

• Not OK - The voltage test lamp did not illuminate.

  Repair: Check the battery voltage at the battery terminals. If the voltage is present at the battery the problem is in the wiring and/or the connectors between the battery and the prelube relay. Repair the wiring and/or the connectors. If the voltage is not present at the battery, refer to Testing and Adjusting, "Electrical System".

  STOP

Test Step 6. Check the Resistance at the Prelube Relay.

1. Turn the Start/Run/Stop switch to the OFF position.

2. Remove the wire from terminal 4 of the prelube relay.

3. Measure the resistance between the wire from terminal 4 and the engine ground.

4. Reconnect all wires.

Expected Result:

The resistance should be less than 10 Ohms.

Results:

• OK - The resistance is less than 10 Ohms.

  Repair: Replace the prelube relay. Verify that the problem is no longer present.

  STOP

• Not OK - The resistance is greater than 10 Ohms.

  Repair: There is a problem in the wiring between the coil of the prelube relay and the engine ground. Repair the wiring and/or replace the wiring. Verify that the problem is no longer present.

  STOP

Test Step 7. Check the Voltage at the Start/Run/Stop Switch.

1. Connect a voltage test lamp between terminal 3 on the Start/Run/Stop switch and the engine ground.

2. Turn the Start/Run/Stop switch to the RUN position.

3. Monitor the voltage test lamp for illumination.

4. Turn the Start/Run/Stop switch to the STOP position.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminated.

  Repair: There is a problem in the wiring and/or connectors between the Start/Run/Stop switch and the prelube relay. Repair the connectors and/or wiring or replace the connectors and/or wiring. Verify that the problem is no longer present.

  STOP

• Not OK - The voltage test lamp did not illuminate. Proceed to test step 8.

Test Step 8. Check the Voltage to the Start/Run/Stop Switch.

1. Connect a voltage test lamp between terminal 2 on the Start/Run/Stop switch and the engine ground.

2. Monitor the voltage test lamp for illumination.

Expected Result:

The voltage test lamp should illuminate.

Results:

• OK - The voltage test lamp illuminated.

  Repair: Replace the Start/Run/Stop switch. Verify that the problem is no longer present.

  STOP

• Not OK - The voltage test lamp did not illuminate.

  Repair: Check the battery voltage at the battery terminals. If the voltage is present at the battery the problem is in the wiring and/or the connectors between the battery and the Start/Run/Stop switch. Repair the wiring and/or the connectors. If the voltage is not present at the battery, refer to Testing and Adjusting, "Electrical System".

  STOP