C-10 and C-15 Petroleum Engines Caterpillar

Use this procedure to troubleshoot any suspected problems with the fuel injectors.

This procedure covers the following diagnostic codes:

• 1-11 Injector Cylinder #1 fault

• 2-11 Injector Cylinder #2 fault

• 3-11 Injector Cylinder #3 fault

• 4-11 Injector Cylinder #4 fault

• 5-11 Injector Cylinder #5 fault

• 6-11 Injector Cylinder #6 fault

• You have been directed to this procedure from Troubleshooting, "Troubleshooting without a Diagnostic Code".

Perform this procedure under conditions that are identical to the conditions that exist when the problem occurs. Typically, problems with the injector solenoid occur when the engine is warmed up and/or when the engine is under vibration (heavy loads).

The engine has electronic unit 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 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.

The injector codes must be programmed into the ECM. The injector code is a four digit number (last four digits of the serial number for the injector) that is found on each of the unit injectors. The ECM uses this number to compensate for manufacturing variations between individual injectors. If you replace any of the unit injectors, you must reprogram the code for the new injectors. Also, if you replace the ECM, you must reprogram all of the injector codes. The ECM will generate a 268-02 Check Programable Parameters if the injector codes have not been programmed.

For more information, refer to the calibration procedure Troubleshooting, "Injector Code - Calibrate".

Illustration 1	g01147070
Mechanical Electronic Unit Injector (MEUI)

Illustration 2	g01146991
Schematic for injector solenoids

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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.

Test Step 1. Inspect Electrical Connectors and Wiring

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position.

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Illustration 3	g01147202
Left side engine view (typical example) (1) J2/P2 ECM connector

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Illustration 4	g01147054
Left side engine view (typical example) (2) J300/P300 Valve cover connector

2. Thoroughly inspect connectors (1) and (2). Ensure that the locking tabs for the valve cover connector are securely locked. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for details.

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Illustration 5	g01147016
P2 ECM connector (P2-33) Injector 1 return (P2-34) Injector 2 return (P2-35) Injector 3 return (P2-36) Injector 4 return (P2-44) Injector 1 & 2 supply (P2-45) Injector 3 & 4 supply (P2-46) Injector 5 & 6 supply (P2-54) Injector 5 return (P2-55) Injector 6 return

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Illustration 6	g01147031
P300 Valve cover connector (wire side) (P300-1) Injector 1 return (P300-2) Injector 2 return (P300-3) Injector 3 return (P300-4) Injector 4 return (P300-5) Injector 5 return (P300-6) Injector 6 return (P300-8) Injector 5 & 6 supply (P300-10) Injector 3 & 4 supply (P300-12) Injector 1 & 2 supply

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors and in the valve cover connector that are associated with injector solenoids.

4. Check the allen head screw on the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

5. Check the harness and wiring for abrasions and for pinch points from the valve cover to the ECM.

Expected Result:

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

Results:

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

• Not OK - There is a problem with the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check for Logged Diagnostic Codes

1. Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.

2. Turn the keyswitch to the ON position.

3. Monitor the "Logged Diagnostic Codes" screen on Cat ET.

Expected Result:

One or more of the following diagnostic codes has been logged:

• 1-11 Injector Cylinder #1 fault

• 2-11 Injector Cylinder #2 fault

• 3-11 Injector Cylinder #3 fault

• 4-11 Injector Cylinder #4 fault

• 5-11 Injector Cylinder #5 fault

• 6-11 Injector Cylinder #6 fault

Results:

• OK - There are logged diagnostic codes for the injectors. Proceed to Test Step 4.

• Not OK - There are no logged diagnostic codes for the injectors. Proceed to Test Step 3.

Test Step 3. Check the Variation of the Injectors Between Each of the Cylinders

1. Start the engine.

2. Allow the engine to warm up to normal operating temperature (approximately 77 °C (171 °F)).

3. After the engine is warmed to operating temperature, access the "Cylinder Cutout Test" on Cat ET by accessing the following display screens in order:
   • "Diagnostics"

   • "Diagnostic Tests"

   • "Cylinder Cutout Test"

4. Enable the cooling fan, if the fan is not controlled by the ECM. If the ECM controls the cooling fan, the cooling fan will start automatically when the test begins.

5. Shut off all parasitic loads such as the air conditioning and the air compressors which could affect the results of the test.

6. Set the engine speed to 1200 ± 20 rpm.

7. Select the start button at the bottom of the screen for the "Cylinder Cutout Test".

8. Select the "4 Cylinder Cutout Test" which is the default test.

9. Follow the instructions that are provided in the "Cylinder Cutout test". The cylinder cutout tests are interactive so the procedure is guided to the finish.

Expected Result:

All cylinders are within specifications.

Results:

• OK - All cylinders are within specifications.

  Repair: If the engine is misfiring or if the engine has low power, refer to the diagnostic procedure Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable" and the diagnostic procedure Troubleshooting, "Low Power/Poor or No Response to Throttle".

  If a diagnostic code results from running the "Cylinder Cutout Test", proceed to Test Step 4.

• Not OK - A problem was found with one of the cylinders. Proceed to Test Step 4.

Test Step 4. Use the Injector Solenoid Test to Check the Operation of the Injector Solenoids

1. Start the engine.

2. Allow the engine to warm up to normal operating temperature (approximately 77 °C (171 °F)).

3. Turn the keyswitch to the OFF position.

4. Turn the keyswitch to the ON position.

5. Access the "Injector Solenoid Test" on Cat ET by accessing the following display screens in order:
   • "Diagnostics"

   • "Diagnostic Tests"

   • "Injector Solenoid Test"

6. Activate the test.

   Note: The test is in the "Interactive Diagnostic Tests". Do not confuse the "Injector Solenoid Test" with the "Cylinder Cutout Test". The "Cylinder Cutout Test" is used to shut off fuel to a specific cylinder while the engine is running. The injector solenoid test is used in order to actuate the injector solenoids. This allows the click of the injector solenoids to be heard when the engine is not running in order to determine that the circuit is functioning properly.

7. 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.

8. Perform the injector solenoid test at least two times.

Expected Result:

All cylinders indicate "OK".

Results:

• OK - There is not an electronic problem with the injectors at this time.

  Repair: If the "Cylinder Cutout Test" returned a "NOT OK" for any injector, refer to the diagnostic procedure Troubleshooting, "Engine Misfires, Runs Rough or Is Unstable".

  STOP

• Not OK - Note the cylinders that indicate "OPEN" and/or "SHORT". Proceed to Test Step 5.

Test Step 5. Use the Injector Solenoid Test to Check for Shorts in the Engine Wiring Harness

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Disconnect the J300/P300 (valve cover connector).

3. Turn the keyswitch to the ON position.

4. Perform the injector solenoid test at least two times.

Expected Result:

All cylinders indicate "OPEN".

Results:

• OK - All cylinders indicate "OPEN". Proceed to Test Step 6.

• Not OK - Note the cylinders that indicate a short circuit. Proceed to Test Step 7.

Test Step 6. Use the Injector Solenoid Test to Check for Opens in the Engine Wiring Harness

Illustration 7	g00706830
Engine harness connector for the injectors

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Disconnect the J300/P300 valve cover connector at the valve cover base.

3. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.

4. Insert one end of the jumper wire into the connector socket for supply wire of the problem injector. Insert the other end of the jumper wire into the appropriate socket for the suspect injector in the P300 valve cover connector. For example, if injector 5 is the problem injector, insert the jumper in terminal 5 and in terminal 8 of the P300 valve cover connector.

5. Turn the keyswitch to the ON position.

6. Perform the injector solenoid test at least two times.

7. Turn the keyswitch to the OFF position.

8. Repeat this test for each suspect Injector. Ensure that the injector solenoid test is disabled before handling the jumper wires.

Expected Result:

Cat ET displays "SHORT" for the cylinder with the jumper wire.

Results:

• OK 1 - Test Step 4 indicated that only one injector had an "OPEN" or "SHORT", or that one injector had an "OPEN" but the other injector on the supply line had a "SHORT". Proceed to Test Step 9.

• OK 2 - Test Step 4 indicated that two injectors that share a supply line are open. Proceed to Test Step 10.

• OK 3 - Test Step 4 indicated that two injectors that share a supply line are shorted. Proceed to Test Step 11.

• Not OK - Proceed to Test Step 8.

Test Step 7. Use the Injector Solenoid Test to Check the ECM for Short Circuits

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Disconnect the J2/P2 ECM connector from the ECM and check for evidence of moisture.

3. Turn the keyswitch to the ON position.

4. Perform the injector solenoid test at least two times.

Expected Result:

All cylinders indicate "OPEN" when the P2 ECM connector is disconnected from the ECM.

Note: When the engine harness is disconnected all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.

Results:

• OK - The short circuit is in the engine harness.

  Repair: Repair the engine harness or replace the engine harness, as required. Clear all diagnostic codes after completing this test step.Verify that the repair eliminates the problem.

  STOP

• Not OK -

  Repair: Perform the following repair:

  1. Temporarily connect a test ECM.

  2. Remove all jumpers and replace all connectors.

  3. Recheck the system for active diagnostic codes.

  4. Repeat the test step.

  5. If the problem is resolved with the test ECM, reconnect the suspect ECM.

  6. If the problem returns with the suspect ECM, replace the ECM.

  7. Verify that the repair eliminates the problem.

  STOP

Test Step 8. Check the ECM For an Open Circuit

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Disconnect the engine harness from the J2 ECM connector. Connect a 140-2266 Cable (Breakout T) to the ECM. Do not connect the engine harness to the Breakout T.

3. Use a jumper wire to short between the socket of the injector and the supply of the suspect injector.

4. Turn the keyswitch to the ON position.

5. Perform the injector solenoid test at least two times.

   Note: When the engine harness is disconnected all of the diagnostic codes for supply voltage to the sensors will be active. This is normal. Clear all of these diagnostic codes after completing this test step.

Expected Result:

Cat ET displays "SHORT" for the cylinder with the jumper wire.

Results:

• OK - The ECM is OK. There is a open in the harness between the valve cover connector P300 and ECM connector P2.

  Repair: Replace the engine harness or repair the engine harness, as required.Verify that the repair eliminates the problem.

  STOP

• Not OK -

  Repair: Perform the following repair:

  1. Temporarily connect a test ECM.

  2. Remove all jumpers and replace all connectors.

  3. Recheck the system for active diagnostic codes.

  4. Repeat the test step.

  5. If the problem is resolved with the test ECM, reconnect the suspect ECM.

  6. If the problem returns with the suspect ECM, replace the ECM.

  7. Verify that the repair eliminates the problem.

  STOP

Test Step 9. Check The Injector Harness Under the Valve Cover

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Remove the valve cover.

3. Disconnect the harness from the problem injector. Disconnect the harness from the other injector that has the same supply line.

4. Thoroughly clean the terminals of both injectors and of the harness.

5. Exchange the harness between the two injectors that share the supply line.

6. Turn the keyswitch to the ON position.

7. Perform the injector solenoid test at least two times.

Expected Result:

Exchanging the harness between the two injectors caused the problem to move to the other injector on Cat ET.

Results:

• OK - Cat ET indicates that the problem has moved.

  Repair: Replace the faulty injector. Restore the wiring to the proper injectors.Verify that the repair eliminates the problem.

  STOP

• Not OK - Cat ET still indicates that the problem is with the original injector.

  Repair: Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.

  STOP

Test Step 10. Check the Engine Harness Under the Valve Cover for an Open Circuit in the Supply Line

Illustration 8	g01147088
Connector terminals for the solenoid connector

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Remove the valve cover.

3. Disconnect each of the injectors that indicate an "OPEN" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.

4. Attach a jumper wire to both terminals of the injector harness for the two injectors that share a supply line.

5. Turn the keyswitch to the ON position.

6. Perform the injector solenoid test at least two times.

Expected Result:

The cylinders with the short in place indicate an "OPEN".

Results:

• OK - The problem appears to be in the engine harness under the valve cover.

  Repair: Perform the following repair:

  1. Replace the engine harness under the valve cover.

  2. Run the injector solenoid test in order to check the installation of the new harness before installing the valve covers.

  3. Verify that the repair eliminates the problem.

  STOP

• Not OK - Both injectors indicate "SHORT".

  Repair: Replace both injectors.Verify that the repair eliminates the problem.

  STOP

Test Step 11. Check the Engine Harness Under the Valve Cover for Short Circuits in the Injector Wires

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Remove the valve cover.

3. Disconnect each of the injectors that indicate a "SHORT" from the wiring harness. Ensure that each of the connectors from the disconnected injector harness does not touch other components and short to ground.

4. Turn the keyswitch to the ON position.

5. Perform the injector solenoid test at least two times.

Expected Result:

Both cylinders indicate an "OPEN".

Results:

• OK - Neither of the injector wires are shorted to the engine.

  Repair: Leave the injector wires disconnected.

  Proceed to Test Step 12.

• Not OK - There is a short in the injector harness under the valve cover.

  Repair: Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.

  STOP

Test Step 12. Check For a Short Circuit in the Supply Line to the Engine

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Disconnect the J2/P2 ECM connector.

3. Locate the supply line for the problem injector in the P2 connector. Measure the resistance from the terminal to the engine ground stud connection.

Expected Result:

The multimeter indicates that the resistance is greater than 5 Ohms.

Results:

• OK - The harness is not shorted to ground.

  Repair: Reconnect the engine harness to the ECM.

  Proceed to Test Step 13.

• Not OK - The harness is shorted to ground.

  Repair: Replace the injector harness under the valve cover.Verify that the repair eliminates the problem.

  STOP

Test Step 13. Check For a Short Circuit in the Injector

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Reconnect one of the two disconnected injectors.

3. Turn the keyswitch to the ON position.

4. Perform the injector solenoid test at least two times.

Expected Result:

The reconnected injector indicates a "SHORT".

Results:

• OK - The injector has an internal short.

  Repair: Replace the Injector.Verify that the repair eliminates the problem.

  STOP

• Not OK - The injector is OK. There may be a problem with the other injector. Proceed to Test Step 14.

Test Step 14. Check For a Short Circuit in the Other Injector

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Electrical shock hazard. The electronic unit injector system uses 90-120 volts.

1. Turn the keyswitch to the OFF position. A strong electrical shock hazard is present if the keyswitch is not turned to the OFF position.

2. Reconnect the other disconnected injector.

3. Turn the keyswitch to the ON position.

4. Perform the injector solenoid test at least two times.

Expected Result:

The reconnected injector indicates a "SHORT".

Results:

• OK - The injector has an internal short.

  Repair: Replace the faulty injector. Restore the wiring to the proper injectors.Verify that the repair eliminates the problem.

  STOP

• Not OK - This injector is OK.

  Repair: There may be an intermittent problem. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP