CYLINDER A 5T6520 - Caterpillar

Use this procedure to troubleshoot high fuel pressure. Also, use this procedure if the following event code is active or logged.
Table 1
J1939 Code and Description CDL Code and Description Comments
94-16
Engine Fuel Delivery Pressure : High - moderate severity (2) E1218 (2)
High Unfiltered Fuel Pressure The fuel pressure before the secondary filter is higher than expected.
Table 2
Associated Codes
J1939 Code CDL Code Troubleshooting Procedure
95-0 E390 (3) Troubleshooting, "Fuel Filter Is Restricted"
95-15 E390 (1) Troubleshooting, "Fuel Filter Is Restricted"
95-16 E390 (2) Troubleshooting, "Fuel Filter Is Restricted" Note: If the priming valve is stuck closed, the fuel pressure high code will become active. The priming valve is normally open, constant voltage or mechanical obstruction can cause the valve to become closed.Probable Causes
Codes
Starting priority valve
Low-pressure regulator
Supply orifice
Back-pressure regulator
Fuel cooler
Priming solenoid valve
Priming loop check valve ( 5000 kPa (725 psi))Recommended Actions
Illustration 1 g06307940
(1) Starting Priority Check Valve
(2) Low-Pressure Fuel System Pressure Regulator
(3) Priming Loop Check Valve
Table 3
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check the Starting Priority Valve
A. Turn the keyswitch to OFF.
B. Remove the starting priority valve from the secondary fuel filter head. Refer to Disassembly and Assembly manual for additional information.
C. Check the starting priority valve operation by actuating the spool within the cartridge assembly.
Priority Valve
Result: The starting priority valve moves freely through the full travel.
Reinstall the starting priority valve.
Proceed to Test Step 3.
Result: The starting priority valve does NOT freely move through the full travel.
Repair: Replace the starting priority valve.
Proceed to Test Step 9.
3. Check is the Fuel Priming Valve Solenoid is Stuck Closed
A. Turn the keyswitch to On.
B. Connect to Cat ET.
C. Perform a priming cycle.
Pressure should measure above 500 kPa (72.5 psi) within 30 seconds.
Fuel Priming Valve Solenoid
Result: The pressure measures above 500 kPa (72.5 psi).
Proceed to Test Step 5.
Result: The pressure measures below 500 kPa (72.5 psi).
Proceed to Test Step 4.
4. Check the Fuel Priming Solenoid Valve
A. Turn the keyswitch to On.
B. Connect to Cat ET.
C. Activate the "Fuel Priming Valve Solenoid Override".
Fuel Priming Solenoid Valve
Result: There is not 24V at the solenoid.
Repair: Check the wiring for the solenoid.
Result: There is 24V at the solenoid.
Repair: Replace the fuel priming valve solenoid.
Proceed to Test Step 9.
5. Check the Low-Pressure Fuel System Pressure Regulator
A. Turn the keyswitch to OFF.
B. Remove the low-pressure fuel system pressure regulator from the secondary fuel filter auxiliary manifold. Refer to Disassembly and Assembly manual for additional information.
C. Check the low-pressure fuel system pressure regulator by actuating the spool within the cartridge assembly.
Pressure Regulator
Result: The low-pressure fuel system pressure regulator moves freely through the full travel.
Reinstall the low-pressure fuel system pressure regulator.
Proceed to Test Step 6.
Result: The low-pressure fuel system pressure regulator does NOT freely move through the full travel.
Repair: Replace the low-pressure fuel system pressure regulator.
Proceed to Test