C175-16 Locomotive Engine Caterpillar

Fuel Pressure Is High

Usage:

Use this procedure to troubleshoot high fuel pressure. Also, use this procedure if the following event code is active or logged.

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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.

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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

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Illustration 1	g06307940
(1) Starting Priority Check Valve (2) Low-Pressure Fuel System Pressure Regulator (3) Priming Loop Check Valve

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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 Step 9.

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Illustration 2	g06307898
(4) Injector Cooling Supply Orifice

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Illustration 3	g06307999
(5) Injector back-pressure regulator

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Table 4
Troubleshooting Test Steps	Values	Results
6. Check the Injector Cooling Supply Orifice A. Turn the keyswitch to OFF. B. Disconnect the injector cooling supply line from the secondary fuel filter head. C. Remove the orifice from the secondary fuel filter head. Refer to Disassembly and Assembly manual for additional information. D. Inspect the injector cooling supply orifice.	Blockage	Result: The injector cooling supply orifice was NOT blocked. Reinstall the injector cooling supply orifice. Proceed to Test Step 7. Result: The injector cooling supply orifice was blocked. Repair: Clean the blockage from the injector cooling supply orifice. Proceed to Test Step 9.
7. Check the Injector Back-Pressure Regulator A. Turn the keyswitch to OFF. B. Remove Injector back-pressure regulator from the low-pressure injector cooling manifold in the fuel cooling rail. Refer to Disassembly and Assembly manual for additional information. C. Check the Injector back-pressure regulator by actuating the spool within the cartridge assembly.	Back-pressure Regulator	Result: The Injector back-pressure regulator moves freely through the full travel. Reinstall the injector back-pressure regulator. Proceed to Test Step 8. Result: The injector back-pressure regulator does NOT freely move through the full travel. Repair: Replace the injector back-pressure regulator. Proceed to Test Step 9.
8. Check the Fuel Cooler A. Turn the keyswitch to OFF. B. Install a pressure gauge in the fuel return line between the high-pressure fuel return line and the customer connection to the fuel cooler and fuel tank. C. Start the engine. D. Run the engine until normal operating temperature has been reached. E. Bring the engine to high idle.	Restriction	Result: The pressure was less than 50 kPa (7.3 psi). Proceed to Test Step 9. Result: The pressure was greater than 50 kPa (7.3 psi). A restricted fuel cooler has been detected. Repair: Replace the fuel cooler. Proceed to Test Step 9.
9. Check for Codes A. Start the engine. B. Run the engine until normal operating temperature has been reached. C. Bring the engine to high idle. D. Connect Cat ET. E. Use Cat ET to monitor for codes.	Codes	Result: A code is not active. Return to service.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).