C7.1 Engines For Caterpillar Built Machines Caterpillar

Probable Causes

• Diagnostic codes

• Electrical connectors

• ECM connection

• Fuel supply

• Intake manifold pressure

Recommended Actions

Diagnostic Codes

Use one of the following methods to check for active diagnostic codes:

• The electronic service tool

• The display on the control panel

Electronic Service Tool

1. Connect the electronic service tool to the diagnostic connector.

2. Check for active diagnostic codes on the electronic service tool.

3. Investigate any active codes before continuing with this procedure. Refer to Troubleshooting, "Troubleshooting with a Diagnostic Code".

Display on the Control Panel

Note: The following procedure is only applicable if the application is equipped with a display on the control panel.

1. Check the display on the control panel for active diagnostic codes.

2. Troubleshoot any active codes before continuing with this procedure. Refer to Troubleshooting, "Troubleshooting with a Diagnostic Code".

Electrical Connectors

1. Refer to Troubleshooting, "Electrical Connectors - Inspect".

2. Repair the electrical connectors or replace the electrical connectors.

3. Ensure that all the connector seals are in place and that the connectors have been correctly installed.

4. Ensure that the repairs have eliminated the fault. If the fault has not been eliminated proceed to "ECM Connection".

ECM Connection

1. Check that the P2/J2 connector is correctly fitted.

2. Check that the P1/J1 connector is correctly fitted.

3. If a fault is suspected with the ECM power and ground connections, refer to Troubleshooting, "Ignition Keyswitch Circuit and Battery Supply Circuit - Test".

4. Verify that the ECM connections for the power and ground connections at the fuel pump are correctly connected.

5. Repair any faults and ensure that the faults have been eliminated.

6. If the repairs do not eliminate the faults, proceed to "Fuel Supply".

Fuel Supply

1. Visually check the fuel tank for fuel. The fuel gauge may be faulty.

2. Ensure that the fuel supply valve (if equipped) is in the full OPEN position.

3. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax).

4. Check the primary filter/water separator for water in the fuel.

5. Check for fuel supply lines that are restricted.

6. Replace the in-line fuel strainer that is installed upstream of the Electric Fuel Lift Pump (EFLP).

7. Check that the Electric Fuel Lift Pump (EFLP) is operating. If the EFLP is suspect, refer to Troubleshooting, "Fuel Pump Relay Circuit - Test".

8. Check that the low-pressure fuel lines are tight and secured properly.

9. Replace the primary fuel filter and the secondary fuel filter. Refer to the Operation and Maintenance Manual, "Fuel System Primary Filter (Water Separator) Element - Replace".

10. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test".

11. Check for air in the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Air in Fuel - Test".

12. Ensure that the fuel system has been primed. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime".

13. Check the fuel pressure. Start the engine and then use the electronic service tool to check that the pressure in the fuel rail is more than 18000 kPa (2610 psi).

14. Turn the keyswitch to the OFF position and then disconnect the electrical connector from the EFLP.

15. With the keyswitch in the ON position, measure the voltage at the harness connector for the EFLP. The voltage must be between 20 VDC and 28 VDC. If the voltage is below 20 VDC, investigate the cause.

16. Turn the keyswitch to the OFF position and then reconnect the electrical connector to the EFLP.

17. If a repair has been performed to rectify a low supply voltage to the EFLP, attempt to start the engine. If the engine does not start, continue with this procedure.

    Note: Before performing the following fuel system tests, the engine must be stopped for a minimum of 30 minutes.

    Note: When performing the following fuel system tests, the Electric Fuel Lift Pump (EFLP) will only operate for 2 minutes unless the engine is running. If necessary, cycle the keyswitch in order to reactivate the pump.

18. Use the following procedure to check the flow from the Transfer Pump Inlet Regulator (TPIR):
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    Illustration 1	g02522678
    Locations in the low-pressure fuel system (1) Fuel return line to the secondary fuel filter (2) Secondary fuel filter base (3) Transfer Pump Inlet Regulator (TPIR) (4) TPIR return port

    1. Disconnect the TPIR return line from the drain port (4) on the TPIR (3). Install a suitable blanking cap on the open port in the TPIR return line

    2. Connect a temporary drain line to the drain port on the TPIR.

    3. Place the end of the temporary drain line into a suitable calibrated container.

    4. With the keyswitch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading.

    5. With the keyswitch in the ON position but the engine not running, measure the fuel flow from the temporary drain line. Refer to Illustration 2 for the minimum acceptable flow rate.
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    Illustration 2	g02522799
    Minimum TPIR flow rate

    6. Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.

    7. If the fuel flow in Step 18.e is greater than the minimum limit, proceed to "Intake Manifold Pressure".

    8. If the fuel flow in Step 18.e is below the minimum limit, continue with this procedure.

19. Use the following procedure to check the fuel flow through the return pressure relief valve in the secondary fuel filter base:

    1. Disconnect the return line (1) from the secondary fuel filter base and install a blank on the line. Install a temporary line and a calibrated container to the filter base.

    2. With the keyswitch in the ON position, measure fuel flow from the temporary line.

    3. If the fuel flow is more than 300 mL/min (10.2 oz/min), replace the secondary fuel filter base. Refer to Disassembly and Assembly, "Fuel Filter Base - Remove and Install (Twin Secondary Fuel Filter)".

    4. Remove the temporary line and reconnect the return line.

20. If the secondary fuel filter base has been replaced, attempt to start the engine. If the engine does not start, use the following procedure to check the fuel flow from the EFLP:

    1. Disconnect the fuel inlet from the primary fuel filter. Place the open end of the disconnected line into a calibrated container.

    2. With the keyswitch in the ON position, measure the flow from the fuel line. Refer to Illustration 3 for the minimum acceptable fuel flow.
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    Illustration 3	g02523082
    Minimum EFLP flow rate

    3. If the fuel flow is more than 5% below the acceptable limit, replace the EFLP.

    4. If the fuel flow is more than 5% above the acceptable limit, contact the Technical Communicator at a Caterpillar dealer.

21. If the fuel flow from the EFLP is within limits, perform the following procedure:

    1. Make sure that the TPIR return line is not blocked or kinked.

    2. If the TPIR return line is clear, confirm that the Electric Fuel Lift Pump (EFLP) is operating. Make sure that fuel lines between the EFLP and the TPIR are not blocked or kinked.

    3. If the fuel lines to the TPIR are clear and the EFLP is operating, replace the TPIR.

22. If the fault is still present, proceed to "Intake Manifold Pressure".

Intake Manifold Pressure

1. Use the electronic service tool to verify the intake manifold pressure.

2. Turn the start switch to the ON position.

3. The intake manifold pressure should read 0 ± 0.5 kPa (0 ± 0.07 psi). If the intake manifold pressure is not within the limits, perform the following steps.

4. Check the air filter restriction indicator, if equipped.

5. Ensure that the air filter is clean and serviceable.

6. Check the air intake and the exhaust system for the following defects:
   • Blockages

   • Restrictions

   • Damage to the air intake and exhaust lines and hoses

7. If the fault cannot be eliminated, contact the technical communicator at a Caterpillar dealer.