Fuel Pressure Is High
Use this procedure to troubleshoot high fuel pressure. Use this procedure if the following event code is active. Refer to Troubleshooting, "Codes" for information about event codes. For information on the engine monitoring system, refer to Troubleshooting, "Engine Monitoring System".
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| 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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| Associated Diagnostic Trouble 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" |
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Check for Codes A. Turn the keyswitch to ON. B. Connect Cat® Electronic Technician (ET) to the service tool connector. C. Turn the keyswitch to ON. D. 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. |
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| |
| Illustration 1 | g06101717 |
|
Typical fuel filter (1) Starting priority valve (2) Low-pressure fuel system pressure regulator | |
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
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 the Disassembly and Assembly manual for proper procedure. C. Check the starting priority valve operation by actuating the spool within the cartridge assembly. |
Starting Priority Valve |
Result: The starting priority valve is OK. Reinstall the starting priority valve. Proceed to Test Step 3. Result: The starting priority valve is NOT OK. Repair: Replace the starting priority valve. Proceed to Test Step 8. |
3. 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 the Disassembly and Assembly manual for proper procedure. C. Check the low-pressure fuel system pressure regulator by actuating the spool within the cartridge assembly. |
Low-Pressure Fuel System Pressure Regulator |
Result: The low-pressure fuel system pressure regulator is OK. Repair: Reinstall the low-pressure fuel system pressure regulator. Proceed to Test Step 4. Result: The low-pressure fuel system pressure regulator is NOT OK. Repair: Replace the low-pressure fuel system pressure regulator. Proceed to Test Step 8. |
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| |
| Illustration 2 | g06101726 |
| (3) Injector cooling orifice fitting | |
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
4. 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 the Disassembly and Assembly manual for proper procedure. D. Inspect the injector cooling supply orifice. |
Blockage |
Result: The injector cooling supply orifice was OK. Repair: Reinstall the injector cooling supply orifice. Proceed to Test Step 5. Result: The injector cooling supply orifice was NOT OK. Repair: Clean the blockage from the injector cooling supply orifice. Proceed to Test Step 7. |
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| |
| Illustration 3 | g06101746 |
| (4) Injector cooling back-pressure regulator | |
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| Troubleshooting Test Steps | Values | Results |
|---|---|---|
5. 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 the Disassembly and Assembly manual for the proper procedure. C. Check the Injector back-pressure regulator by actuating the spool within the cartridge assembly. |
Injector Back-pressure Regulator |
Result: The injector back-pressure regulator is OK. Repair: Reinstall the injector back-pressure regulator. Proceed to Test Step 6. Result: The injector back-pressure regulator is NOT OK. Repair: Replace the injector back-pressure regulator. Proceed to Test Step 7. |
6. Check the Fuel Cooler (If Equipped) 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 and operate at high idle. |
Restriction |
Result: The pressure was less than Proceed to Test Step 7. Result: The pressure was greater than Repair: Replace the fuel cooler. Proceed to Test Step 7. |
7. Check for Codes A. Start the engine and operate at high idle for 1 minute. B. Look for active or logged diagnostic codes. |
Codes |
Result: No codes present. 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).
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