C27 Petroleum Generator Set Engines Caterpillar

The following lists the probable causes of high fuel pressure:

• Fuel pressure sensor

• Fuel lines

• Fuel pressure regulator

• Pressure relief valve for the fuel transfer pump

Note: High fuel pressure may cause high fuel temperatures. Troubleshoot a code for high fuel pressure before troubleshooting a code for high fuel temperature.

Use this procedure in order to troubleshoot high fuel pressure. Also use this procedure if one of the following diagnostic trouble codes is active. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. Refer to Troubleshooting, "Engine Monitoring Parameters" for information about engine events.

Test Step 1. Determine the Code

1. Connect Cat ET to the service tool connector. Refer to Troubleshooting, "Electronic Service Tools", if necessary.

2. Determine if a diagnostic trouble code is present.

Results:

• Active 5580-16 - The 5580-16 is active or logged. Proceed to Test Step 2.

• Unrelated Code Present - There are unrelated codes that are present.

  Repair: Troubleshoot the code. Refer to the proper troubleshooting procedure.

  STOP

Test Step 2. Compare the Status of Fuel Pressure in Cat ET to a Mechanical Gauge

Illustration 1	g02167853
Secondary fuel filter mounting (1) Fuel temperature sensor (2) Fuel pressure sensor (filtered fuel pressure)

Note: Do not use the sampling port for measuring the fuel pressure.

1. Record the fuel pressure from Cat ET. Record the data in Table 3.

2. Remove fuel pressure sensor (2).

3. Install a 8T-7860 Connector into the port of the pressure sensor.

4. Install the 110-6349 Fitting As onto the 8T-7860 Connector.

5. Install a 8T-0855 Pressure Gauge onto a 6V-3990 Coupler.

6. Install the 6V-3990 Coupler onto the 110-6349 Fitting As.

7. Record the fuel pressure on the pressure gauge. Record the data in Table 3.

Expected Result:

The value of the fuel pressure is within 137 kPa (20 psi) of the fuel pressure reading that is shown in Cat ET.

Results:

• OK - The pressures are comparable. Proceed to Test Step 3.

• Not OK - The value of the fuel pressure is not within 137 kPa (20 psi) of the fuel pressure reading that is shown in Cat ET.

  Repair: Replace the pressure sensor. Verify that the problem has been resolved.

  If the problem is not resolved, proceed to Test Step 3.

Test Step 3. Inspect the Fuel Lines

Illustration 2	g02158580
Fuel lines

1. Visually inspect the fuel lines between the primary filter base and the inlet to the cylinder head. Also, inspect the fuel cooler, if equipped. Inspect the fuel return lines from the cylinder head to the fuel tank. Inspect the lines for restrictions, pinching, and swelling.

Expected Result:

The fuel lines and the cooler (if equipped) are in good repair.

Results:

• OK - The fuel lines are OK. Proceed to Test Step 4.

• Not OK - The fuel lines and the cooler (if equipped) are not OK.

  Repair: Perform the necessary repairs. Verify that the problem has been resolved.

  If the problem is not resolved, proceed to Test Step 4.

Test Step 4. Replace the Fuel Pressure Regulator

Illustration 3	g02140923
Location of the fuel pressure regulator

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Contact with high pressure fuel may cause fluid penetration and burn hazards. High pressure fuel spray may cause a fire hazard. Failure to follow these inspection, maintenance and service instructions may cause personal injury or death.

1. Replace the fuel return pressure regulator.

2. Use Cat ET to check if the original code remains active.

Expected Result:

The code is no longer active.

Results:

• OK - The code is no longer active.

  Repair: The fuel pressure is within specifications. Return the engine to service.

  STOP

• Not OK - The original code remains active. Proceed to Test Step 5.

Test Step 5. Inspect the Pressure Relief Valve for the Fuel Transfer Pump

Illustration 4	g02140700
Location of the pressure relief valve for the fuel transfer pump

1. Inspect the condition of the spring for the pressure relief valve that is integral to the fuel transfer pump. The spring must be in good repair.

Expected Result:

The pressure relief valve and the spring are in good repair.

Results:

• OK - The relief valve and the spring appear to be in good repair.

  Repair: Clean the relief valve and reinstall the relief valve. Verify that the problem has been resolved.

  STOP

• Not OK - The relief valve and the spring are suspect.

  Repair: Install a spring kit for the pressure relief valve. If the problem persists, replace the fuel transfer pump. Verify that the problem has been resolved.

  STOP