3512B Marine Auxiliary Engine Caterpillar

The engine has Electronic Fuel Injectors that are mechanically actuated and electronically energized. The Electronic Control Module (ECM) sends a 105 volt pulse to each injector solenoid. The pulse is sent at the proper time and at the correct duration for a given engine load and speed. The solenoid is mounted on top of the fuel injector body. The 105 volt pulse can be individually cut out to aid in troubleshooting misfire problems.

If an open is detected in the solenoid circuit, a diagnostic code is generated. The ECM continues to try to fire the fuel injector. If a short is detected, a diagnostic code is generated. The ECM will disable the solenoid circuit. The ECM will then enable the solenoid. If the short circuit remains this sequence of events will be repeated until the problem is corrected.

Illustration 1	g00621954

Test Step 1. Check for Connector Damage.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Perform the diagnostic functional test 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:

Ensure that all connectors, pins, and sockets have good electrical connections. The harness and wiring should be free of corrosion, abrasion or pinch points.

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK - The connectors and/or wiring need repair.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 2. Check for LOGGED Diagnostic Codes.

1. Connect the Caterpillar Electronic Technician (ET).

2. Turn the circuit breaker for the battery to the ON position.

3. Turn the ECS to the STOP position.

4. Observe the diagnostic codes on the Cat ET.

Expected Result:

A CID-FMI from 1-05 to 12-05 or from 1-06 to 12-06 should not be logged.

Results:

• OK - A CID-FMI from 1-05 to 12-05 or from 1-06 to 12-06 is not logged. Proceed to test step 3.

• Not OK - A CID-FMI from 1-05 to 12-05 or from 1-06 to 12-06 is logged. Proceed to test step 4.

Test Step 3. Perform the Injector Solenoid Test.

Note: This test will help the service technician verify that the ECM can fire the solenoids. DO NOT try to manually crank the engine during this test. The ECM will terminate the Injector Solenoid Test.

1. Perform this test on both Electronic Control Modules.

2. Turn the circuit breaker for the battery to the OFF position.

3. Turn the ECS to the OFF/RESET position.

4. Ensure that the ECM connector J2/P2 is connected. Ensure that the injector connectors J4/P4 through J15/P15 are connected.

5. Connect the Cat ET.

6. Turn the circuit breaker for the battery to the ON position.

7. Turn the ECS to the STOP position.

8. Use Diagnostic Tests on the Cat ET to initiate the Injector Solenoid Test.

9. As each solenoid is energized by the ECM an audible click can be heard at the valve cover. Listen for a click at each valve cover. A black square will appear over the cylinder number when the cylinder is being fired.

   Note: A false reading may result from the initial test. By the fourth consecutive test, the readings should become valid.

10. Perform this test on the Secondary ECM also.

Expected Result:

As each solenoid is energized by the ECM, an audible click of the solenoid should be heard. The solenoids will be energized one at a time in the following numerical order: 1-12. There will be momentary delay between each one.

Results:

• OK - As each solenoid is energized an audible click is heard. Proceed to test step 5.

• Not OK - Verify that the ECM is receiving correct battery power.

  Repair: Perform the diagnostic functional test Troubleshooting, "Electrical Power Supply".

  Stop.

Test Step 4. Check for a Short between Wires in the Harness.

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This engine uses high voltage to control the fuel injectors. Disconnect the fuel enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Disconnect J2/P2 and J4/P4 through J15/P15.

4. Measure the resistance between the solenoid wire pairs at the ECM connector P2.

   For an engine with twelve cylinders, measure the resistance at the following points:

   • Measure the resistance for SOLENOID 1 at P2-16 and P2-5.

   • Measure the resistance for SOLENOID 2 at P2-40 and P2-11.

   • Measure the resistance for SOLENOID 3 at P2-26 and P2-5.

   • Measure the resistance for SOLENOID 4 at P2-34 and P2-11.

   • Measure the resistance for SOLENOID 5 at P2-32 and P2-17.

   • Measure the resistance for SOLENOID 6 at P2-28 and P2-21.

   • Measure the resistance for SOLENOID 7 at P2-38 and P2-17.

   • Measure the resistance for SOLENOID 8 at P2-22 and P2-21.

   • Measure the resistance for SOLENOID 9 at P2-37 and P2-27.

   • Measure the resistance for SOLENOID 10 at P2-18 and P2-33.

   • Measure the resistance for SOLENOID 11 at P2-31 and P2-27.

   • Measure the resistance for SOLENOID 12 at P2-12 and P2-33.

Expected Result:

The resistance should be greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. Proceed to test step 6.

• Not OK - The resistance is less than 20,000 Ohms. There is a problem in the wiring harness.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 5. Perform the Cylinder Cutout Test.

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NOTICE
Engine power is reduced when a properly functioning cylinder is cut out. Make sure that you will not damage auxiliary or driven equipment if the engine power is suddenly reduced.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Verify that the ECM connector J2/P2 and the injector connectors J4/P4 through J15/P15 are properly connected.

4. Turn the circuit breaker for the battery to the ON position.

5. Install the Cat ET.

6. Start the engine.

7. Apply a load to the engine.

8. Use the diagnostic tests on the Cat ET to initiate the injector solenoid test.

9. Check for a difference in the sound, feel, or power of the engine as each cylinder is cut out. The amount of change should be similar for all of the good cylinders. The amount of change should be minimal for a weak cylinder or a bad cylinder.

10. Disable the override. Repeat above steps for each cylinder (solenoid).

Expected Result:

The amount of change should be similar for all of the good cylinders. The amount of change should be minimal for a weak cylinder or a bad cylinder.

Results:

• OK - There was a similar change in the sound, feel, or power of the engine as each cylinder was cut out. The injectors are okay. Stop.

• Not OK - There was no change in the sound, feel, or power of the engine as each cylinder was cut out. Proceed to test step 7.

Test Step 6. Check the Harness for a Short to Engine Ground.

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This engine uses high voltage to control the fuel injectors. Disconnect the fuel enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Measure the resistance between the individual solenoid wires and engine ground at connector P2:

   For an engine with twelve cylinders, measure the resistance at the following points:

   • Measure the resistance between P2-5 and engine ground.

   • Measure the resistance between P2-11 and engine ground.

   • Measure the resistance between P2-12 and engine ground.

   • Measure the resistance between P2-16 and engine ground.

   • Measure the resistance between P2-17 and engine ground.

   • Measure the resistance between P2-18 and engine ground.

   • Measure the resistance between P2-21 and engine ground.

   • Measure the resistance between P2-22 and engine ground.

   • Measure the resistance between P2-26 and engine ground.

   • Measure the resistance between P2-27 and engine ground.

   • Measure the resistance between P2-28 and engine ground.

   • Measure the resistance between P2-31 and engine ground.

   • Measure the resistance between P2-32 and engine ground.

   • Measure the resistance between P2-33 and engine ground.

   • Measure the resistance between P2-34 and engine ground.

   • Measure the resistance between P2-37 and engine ground.

   • Measure the resistance between P2-38 and engine ground.

   • Measure the resistance between P2-40 and engine ground.

Expected Result:

The resistance should be greater than 20,000 Ohms.

Results:

• OK - The resistance is greater than 20,000 Ohms. Proceed to test step 11.

• Not OK - The resistance is less than 20,000 Ohms. There is a problem in the wiring harness.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.

Test Step 7. Check the Spring and the Valve Lash.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Check the Injector and the engine Valve Lash Setting. Refer to the Systems Operation.

Results:

• OK - The injectors and valve lash setting appear to be okay. Stop.

• Not OK - A problem is found with the injector.

  Repair: Refer to Systems Operation.

  Stop.

Test Step 8. Check the Diode Assembly.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Set a voltmeter to the "diode check" setting. Remove the Diode Assembly J62 for Cylinder number 1.

4. Connect the positive lead to pin-1 and the negative lead to pin-4. The display should show a number less than 0.4 ± 0.1.

5. Connect the positive lead to pin-2 and the negative lead to pin-3. The display should show a number less than 0.4 ± 0.1.

6. Connect the negative lead to pin-1 and the positive lead to pin-4. The display should indicate an open circuit ".OL".

7. Connect the negative lead to pin-2 and the positive lead to pin-3. The display should indicate an open circuit ".OL".

8. Record the measurements of each pair. Continue testing the Diode Assemblies J63 through J73.

Expected Result:

The diode assembly should measure 0.4 ± 0.1 VDC when the positive lead is connected to the anode and the negative lead is connected to the cathode of the diode. The diode assembly should measure ".OL" when the negative lead is connected to the anode and the positive lead is connected to the cathode of the diode.

Results:

• OK - The diode assembly is okay. Proceed to test step 9.

• Not OK - There is a problem with a diode assembly.

  Repair: Temporarily replace the diode assembly. Verify that the problem is no longer present. Reinstall the old diode. If the problem returns replace the diode.

  Stop.

Test Step 9. Measure the Resistance of the Injector Solenoids through the Harness Yoke.

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Personal injury can result from high voltage. The Electronic Control Module produces high voltage. Make sure the Electronic Control Module is not powered and the fuel injector solenoids are disconnected before proceeding.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Ensure that the ECM connector J2/P2 is disconnected. Ensure that the injector connectors J4/P4 through J15/P15 are disconnected.

4. Measure the solenoid resistance between pin-1 and pin-2 at J4 through J15.

5. Record the measured resistance for each solenoid.

Expected Result:

The resistance should be between 0.5 and 1.5 Ohms.

Results:

• OK - The resistance is between 0.5 and 1.5 Ohms. Proceed to test step 3.

• Not OK - The resistance is not between 0.5 and 1.5 Ohms. Proceed to test step 10.

Test Step 10. Check the Resistance of the Injector Solenoids and Check for Shorts.

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This engine uses high voltage to control the fuel injectors. Disconnect the fuel enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running.

1. Turn the ECS to the OFF/RESET position.

2. Remove the valve cover of the suspected cylinder.

3. Remove the harness yoke from the solenoid terminals.

4. Measure the resistance between the two solenoid terminals on top of the injector. Record the resistance.

5. Measure the resistance from either solenoid terminal to the fuel injector body (metal). Record the resistance.

6. Reconnect the harness yoke and install the valve cover.

Expected Result:

Resistance between the two solenoid terminals should be between 0.5 and 1.5 Ohms. Resistance from either solenoid terminal to the fuel injector body (metal) should be greater than 20,000 Ohms.

Results:

• OK - The injector is okay.

  Repair: The harness yoke has a short or an open. Repair the harness yoke or replace the harness yoke.

  Stop.

• Not OK - The injector has failed.

  Repair: Repair the injector. If the problem is still present, replace the injector. If the new injector has a 4-Digit code that is different from the old injector, change the code in the ECM.

  Stop.

Test Step 11. Check for an Open in the Harness.

1. Use a suitable piece of wire to short socket-1 to socket-2 at each solenoid connector. Also shortsocket-1 to socket-4 at each diode assembly. Short socket-2 to socket-3 at each diode assembly.

2. Measure the resistance between the following solenoid wire pairs in connector P2:

   For an engine with twelve cylinders, measure the resistance at the following points:

   • Measure the resistance for SOLENOID 1 at P2-16 and P2-5.

   • Measure the resistance for SOLENOID 2 at P2-40 and P2-11.

   • Measure the resistance for SOLENOID 3 at P2-26 and P2-05.

   • Measure the resistance for SOLENOID 4 at P2-34 and P2-11.

   • Measure the resistance for SOLENOID 5 at P2-32 and P2-17.

   • Measure the resistance for SOLENOID 6 at P2-28 and P2-21.

   • Measure the resistance for SOLENOID 7 at P2-38 and P2-17.

   • Measure the resistance for SOLENOID 8 at P2-22 and P2-21.

   • Measure the resistance for SOLENOID 9 at P2-37 and P2-27.

   • Measure the resistance for SOLENOID 10 at P2-18 and P2-33.

   • Measure the resistance for SOLENOID 11 at P2-31 and P2-27.

   • Measure the resistance for SOLENOID 12 at P2-12 and P2-33.

   Note: Repeat this test step for the Secondary ECM.

Expected Result:

The resistance should be less than 10 Ohms.

Results:

• OK - The resistance is less than 10 Ohms. Proceed to test step 8.

• Not OK - The resistance is greater than 10 Ohms. There is a problem in the wiring harness.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring.

  Stop.