The engine uses 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. If a diagnostic is detected in the solenoid circuit, the ECM will disable that solenoid circuit. The ECM keeps the solenoid circuit disabled for 10 revolutions of the crankshaft. The ECM then tries to fire the injector. If the diagnostic is still present, the ECM will disable the circuit for another 10 revolutions of the crankshaft. This sequence of events will be repeated indefinitely until the problem is corrected.
The Cylinder Cutout Test on the Caterpillar Electronic Technician (ET) can be used to troubleshoot misfire problems. The Cylinder Cutout Test cuts out the 105 volt pulse to the injector solenoids. The injector solenoid is mounted on top of the fuel injector body.
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| Illustration 1 | g00919579 |
Test Step 1. Check for Connector Damage.
- Turn the keyswitch to the OFF position.
- Turn the battery disconnect switch to the OFF position.
- Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors" for details.
- Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
- Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).
- Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).
- Check the harness and the wiring for abrasion and for 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, of abrasion or of pinch points.
Results:
- OK - The connectors and wiring are okay. Proceed to test step 2.
- Not OK - The connectors and/or wiring are not okay.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
Stop.
Test Step 2. Check for LOGGED Diagnostic Codes.
- Connect the Cat ET to the service tool connector J42/P42.
- Turn the battery disconnect switch to the ON position.
- Turn the keyswitch to the STOP position.
- Observe the diagnostic codes on the Cat ET.
Expected Result:
A CID-FMI 1-05 to 16-05 or 1-06 to 16-06 should not be logged.
Results:
- OK - A CID-FMI 1-05 to 16-05 or 1-06 to 16-06 is not logged. Proceed to test step 3.
- Not OK - A CID-FMI 1-05 to 16-05 or 1-06 to 16-06 is logged. Proceed to test step 5.
Test Step 3. Perform the Cylinder Cutout Test.
- Turn the keyswitch to the OFF position.
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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. |
- Turn the battery disconnect switch to the OFF position.
- Verify that the ECM connector J2/P2 and the injector connectors J4/P4 through J19/P19 are properly connected.
- Install the Cat ET.
- Turn the battery disconnect switch to the ON position.
- Turn the keyswitch to the START position.
- Start the engine.
- Apply a load to the engine.
- Perform the following steps on all suspect cylinders (solenoids).
- Use the diagnostic tests on the Cat ET to initiate the Cylinder Cutout Test.
- 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.
- Disable the override.
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 noticeable change in engine performance during the Cylinder Cutout Test.
Repair: The injectors are firing in all cylinders. Reset the system and check for diagnostic codes.
Stop.
- Not OK - There was no noticeable change in engine performance during the Cylinder Cutout Test. Proceed to test step 4.
Test Step 4. Check the Injector Lash and the Engine Valve Lash Setting.
- Turn the keyswitch to the OFF position.
- Turn the battery disconnect switch to the OFF position.
- Check the injector and the engine valve lash setting. Refer to Testing and Adjusting, "Fuel Injector Adjustment".
Expected Result:
The engine valve lash setting is correct. The injectors are okay.
Results:
- OK - The injector is okay. Proceed to test step 5.
- Not OK - The injector is not okay. A problem is found with the injector.
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 5. Check the Resistance of the Harness from the Solenoid to the ECM Connector.
- Turn the keyswitch to the OFF position.
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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running. |
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- Turn the battery disconnect switch to the OFF position.
- Disconnect ECM connector J2/P2 and injector connectors J4/P4 through J19/P19.
- Measure the resistance at ECM connector P2 between the sockets for power output and the solenoid return for the individual solenoid. Refer to Illustration 1.
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.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
Stop.
Test Step 6. Check for Shorts in the Harness to Engine Ground.
- Measure the resistance at the ECM connector between the following points and engine ground: P2-4, P2-5, P2-6, P2-10, P2-11, P2-12, P2-16, P2-17, P2-18, P2-21, P2-22, P2-26, P2-27, P2-28, P2-30, P2-31, P2-32, P2-33, P2-34, P2-36, P2-37, P2-38, P2-39 and P2-40.
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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running. |
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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 7.
- Not OK - The resistance is less than 20,000 Ohms.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
Stop.
Test Step 7. Check for Open Circuits in the Harness.
- Use a suitable piece of wire to short socket 1 to socket 2 at each injector connector.
- Measure the resistance at ECM connector P2 between the sockets for power output and the solenoid return for the individual solenoid. Refer to Illustration 1.
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.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
Stop.
Test Step 8. Measure the Resistance at the Valve Cover Base.
- Measure the solenoid resistance between pin 1 and pin 2 at J4/P4 through J19/P19.
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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. |
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- Record the measured resistance for each solenoid.
Expected Result:
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 9.
- Not OK - The resistance is not between 0.5 and 1.5 Ohms. Proceed to test step 10.
Test Step 9. 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.
- Ensure that the ECM connector J2/P2 is connected. Ensure that the injector connectors J4/P4 through J19/P19 are connected.
- Connect the Cat ET.
- Turn the battery disconnect switch to the ON position.
- Turn the keyswitch to the STOP position.
- Use the diagnostic tests on the Cat ET to initiate the Injector Solenoid Test.
- 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. On the Cat ET screen, a black square will appear over the cylinder number as the cylinder is being fired.
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 to 16. There will be a momentary delay between each one.
Results:
- OK - The audible click is heard for each solenoid. Proceed to test step 3.
- Not OK - The audible click is not heard for each solenoid.
Repair: Perform the diagnostic functional test Troubleshooting, "Electrical Power Supply".
Stop.
Test Step 10. Check the Resistance of the Injector Solenoid.
- Turn the keyswitch to the OFF position.
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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. |
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- Turn the battery disconnect switch to the OFF position.
- Remove the valve cover of the suspected cylinder.
- Remove the harness yoke from the solenoid terminals.
- Measure the resistance between the two solenoid terminals on top of the injector. Record the resistance.
- Measure the resistance from either solenoid terminal to the fuel injector body (metal).
- Record the resistance.
- 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 - All resistance readings are within limits. There is a problem in the valve cover base harness.
Repair: Repair the connectors or wiring and/or replace the connectors or wiring.
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.