C175 Tier 4 Final Engines for Off-Highway Trucks Caterpillar

Fuel Flow Is High

Usage:

793F D3T

Use this procedure to troubleshoot a high fuel flow in the high-pressure fuel system. Also, use this procedure if the following event code is active.

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Table 1
J1939 Code and Description	CDL Code and Description	Comments
157-17 Engine Injector Metering Rail #1 Pressure : Low - least severe (1)	E398(1) Low Fuel Rail Pressure	The fuel rail pressure is below an acceptable level. The code is logged. The check engine light will illuminate.
157-18 Engine Injector Metering Rail #1 Pressure : Low - moderate severity (2)	E398(2) Low Fuel Rail Pressure	The fuel rail pressure is below an acceptable level. The code is logged. The check engine light will illuminate.
1440-0 Engine Fuel Flow Rate #1 : High - most severe (3)	E1106(3) High Fuel Rail Pump Flow	There is excessive leakage in the high-pressure fuel system. The code is logged. The check engine light will illuminate.
1440-15 Engine Fuel Flow Rate #1 : High - least severe (1)	E1106(1) High Fuel Rail Pump Flow	There is excessive leakage in the high-pressure fuel system. The code is logged. The check engine light will illuminate.
1440-16 Engine Fuel Flow Rate #1 : High - moderate severity (2)	E1106(2) High Fuel Rail Pump Flow	There is excessive leakage in the high-pressure fuel system. The code is logged. The check engine light will illuminate.
5585-17 Engine Injector Metering Rail #1 Cranking Pressure : Low - least severe (1)	E1220(1) Low Cranking Fuel Rail Pressure	The fuel rail pressure is too low while cranking. This can be caused by a fuel system service prior to starting the engine.

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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"
5578-3	289-3	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
5578-4	289-4	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
5580-3	460-3	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
5580-4	460-4	Troubleshooting, "Sensor Signal (Analog, Active) - Test"
5580-17	E198(1)	Troubleshooting, "Fuel Pressure Is Low"
5580-18	E198(2)	Troubleshooting, "Fuel Pressure Is Low"

Probable Causes

Diagnostic codes and event codes
Pressure relief valve leakage
High-pressure fuel pump leakage
High-pressure fuel rail leakage
Fuel control valve problem

Recommended Actions

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Table 3
Troubleshooting Test Step	Value	Result
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. Refer to the appropriate troubleshooting story. Result: An E1220 or a 5585–17 code is present. Proceed to Test Step 2. Result: An E398, E1106, 157, or a 1440 code is present. Proceed to Test Step 3.
2. Check the Service History. A. An E1220 or 5585-17 code can be caused by a recent service on the fuel system. If the high-pressure system was not primed after the last service, this code will log. B. Prime the fuel system. C. Turn the keyswitch to ON. D. Connect Cat ET. E. Clear the fault E1220 or 5585-17 code. F. Start the engine.	Code	Result: An E1220 or a 5585-17 code came active after clearing. Proceed to Test Step 4. Result: An E1220 or a 5585-17 code did not come active. The high-pressure fuel system was not properly primed. Proceed to Test Step 12.
3. Perform a "Fuel System Functional Test" A. Turn the keyswitch to ON. B. Connect Cat ET. C. Start the engine. D. Perform the "Fuel System Functional Test". E. Once the test has completed, turn the keyswitch to the OFF position. F. Wait for 2 minutes to allow the pump diagnostics to run. G. Turn the keyswitch to ON. H. Connect Cat ET. I. Check for active diagnostic codes.	Test Successful	Result: The "Fuel System Functional Test" passed successfully and there are no active codes. Repair Complete. Result: There was a 1684 or 1077 code present after running the "Fuel System Functional Test". A failed high-pressure fuel pump has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last two fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Repair: Replace the high-pressure fuel pump. Proceed to Test Step 12. Result: The test failed for an E111F - Fuel Flow Too Low. A failed high-pressure fuel pump has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last two fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Repair: Replace the high-pressure fuel pump. Proceed to Test Step 12. Result: The test failed for an E111D - Fuel Rail High Pressure Decay Too High Proceed to Test Step 4. Result: The test failed for an E111E - Fuel Rail Low Pressure Decay Too High Proceed to Test Step 4.
4. Verify the Fuel Rail Pressure Sensor Reading A. Turn the keyswitch to OFF. B. Release the pressure in the high-pressure rail by loosening the end plug on one of the last two fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. C. Turn the keyswitch to ON. D. Connect Cat ET. E. Monitor the "Fuel Rail Pressure" parameter in Cat ET.	Fuel Pressure	Result: The "Fuel Rail Pressure" is 0 ± 8 MPa (1160 psi). Proceed to Test Step 5. Result: The "Fuel Rail Pressure" not 0 ± 8 MPa (1160 psi). A failed fuel rail pressure sensor has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last two fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Repair: Replace the fuel rail pressure sensor. Proceed to Test Step 12.
5. Check for Visible External Leaks in the Fuel System A. Turn the keyswitch to OFF. B. Visually inspect the entire fuel systems for any signs of leaks.	Leaks	Result: No visible leaks are present. Proceed to Test Step 6. Result: A leak was detected. Repair: Repair the leak in the fuel system. Proceed to Test Step 12.

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Illustration 1	g06190372
(1) HP junction block (2) Check valve

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Table 4
Troubleshooting Test Step	Value	Result
6. Check for Internal High-Pressure Fuel Line Leaks A. Turn the keyswitch to OFF. B. Disconnect the fuel double wall fuel return line between the check valve and the high-pressure junction block. C. Place the double wall fuel return line into a suitable container. D. Crank / Start the engine and check for fuel leakage.	Fuel Volume	Result: There was leakage from the fuel return line. Leave the high-pressure fuel return line disconnected from the check valve at the junction block. Proceed to Test Step 7. Result: There was no leakage from the fuel return line. Proceed to Test Step 10.
7. Check the Torque on the High-Pressure Lines and Accumulator Quill Tube Connections A. Turn the keyswitch to OFF. B. Check the torque on each one of the high-pressure fuel lines and accumulator quill tube connections. C. Check the torque on the high-pressure fuel accumulator quill tube studs.	Torque Value	Result: All torque values were within specification. Proceed to Test Step 8. Result: The torque values were not all within specification. Repair: Tighten the lines and/or accumulator quills that were not properly torqued. Proceed to Test Step 12.

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Illustration 2	g06041456
HP accumulator-quill (3) Leak detection plug/port

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Table 5
Troubleshooting Test Step	Value	Result
8. Check the Leak Detection Ports on the Fuel Accumulator Quill Tubes. A. Turn the keyswitch to OFF. B. Remove all the leak detection port on each of the fuel accumulator quill tubes. C. Crank/Start the engine. D. If the engine can be started. Operate the engine at low idle and high idle. E. Inspect each of the leak detection ports for signs of fuel leakage. Note: Fuel leakage may occur, be prepared to collect leaking fuel.	Fuel Leak	Result: A leak was detected on the accumulator quill tube leak port. Repair: A high-pressure fuel leak has been detected. A leak at the high-pressure fuel supply line on each side of the leaking accumulator quill tube has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Replace the high-pressure fuel supply line on each side of the leaking accumulator quill tube. Proceed to Test Step 9. Result: A leak was detected on the high-pressure return line. Repair: A high-pressure fuel leak has been detected. A leak at the high-pressure fuel return line was detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Replace the high-pressure fuel return line. Proceed to Test Step 12. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Result: There were no leaks detected. Repair: There is a high-pressure fuel leak before the injector bank. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Remove and inspect all the high-pressure lines between the high-pressure fuel pump and each injector bank. Replace the lines if necessary. Torque the lines to the proper value upon reinstallation. Proceed to Test Step 12.
9. Check the Leak Detection Ports on the Fuel Accumulator Quill Tubes. A. Turn the keyswitch to OFF. B. Remove the all the leak detection port on each of the fuel accumulator quill tubes. C. Crank/Start the engine. D. If the engine can be started. Operate the engine at low idle and high idle. E. Inspect each of the leak detection ports for signs of fuel leakage.	Fuel Leak	Result: A leak was detected on the accumulator quill tube leak port. Repair: A high-pressure fuel leak has been detected. A failed high-pressure fuel crossover line has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Replace the high-pressure fuel crossover line nearest to the leaking accumulator quill tube. Proceed to Test Step 12. Result: There were no leaks detected. Repair: There is a high-pressure fuel leak before the injector bank. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Remove and inspect all the high-pressure lines between the high-pressure fuel pump and each injector bank. Replace the lines if necessary. Torque the lines to the proper value upon reinstallation. Proceed to Test Step 12.
10. Check the Torque on the High-Pressure Lines and Quill Tubes A. Turn the keyswitch to OFF. B. Check the torque on each one of the high-pressure fuel lines and accumulator quill tubes.	Torque Value	Result: All torque values were within specification. Proceed to Test Step 11. Result: The torque values were not all within specification. Repair: Tighten the lines and/or accumulator quills that were not properly torqued. Proceed to Test Step 12.

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Illustration 3	g06088551
Fuel Injector Cooling Circuit (5) Return Lines (6) Supply Lines

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Table 6
Troubleshooting Test Step	Value	Result
11. Check for a Leak into the Injector Cooling Circuit A. Turn the keyswitch to the OFF position. B. Disconnect the injector cooling circuit supply line from the injector cooling supply orifice fitting. C. Cap the injector cooling supply line end with contamination control part number 9U-7079 Tapered Cap/Plug. D. Install a threaded plug on the injector cooling circuit orifice fitting to seal orifice so no fuel comes from the manifold during cranking. Use 6V-9831 Cap As. E. Disconnect the injector cooling circuit fuel return lines from the joints to the cylinder heads. The injector cooling circuit return line is on the left side of the cylinder head and connects to the lower injector cooling fuel rail F. Turn the keyswitch to the ON position. G. Connect Cat ET. H. Using Cat ET set the "Fuel Injection Enable Status" in the configuration screen to "Disabled". Note: This must be done to prevent damage to the fuel injectors. I. Crank the engine for 30 seconds for 3 cycles. Note: A prelube cycle must complete prior to allowing the engine to crank on some engines. The prelube cycle could take up to 30 seconds. The engine will only crank for 30 seconds at a time to protect the starter. Then the engine will require 30 seconds to cool back down. K. Inspect each of the injector cooling circuit return ports on the cylinder head for signs of fuel leakage. Note: Fuel leakage may occur, be prepared to collect leaking fuel.	Fuel Leak	Result: There was no fuel leakage detected. Repair: Using Cat ET set the "Fuel Injection Enable Status" in the configuration screen to "Enabled". Reconnect the speed/timing sensors. Reconnect all the injector cooling circuit return lines that were removed. Proceed to Test Step 12. Result: A fuel leak from the injector cooling circuit return port was detected. Repair: A quill tube leaking into the injector cooling circuit has been detected. Release the pressure in the high-pressure rail by loosening the end plug on one of the last 2 fuel accumulators. Refer to Testing and Adjusting, "Fuel Rail Pressure - Release" for instructions on how to release the pressurized fuel. Verify that the "Fuel Rail Pressure" reading in ET is 0 ± 8 MPa (1160 psi) prior to servicing the fuel system. Remove the quill tube and the injector and inspect the mating surfaces for signs of damage. Replace if necessary. Reassemble the fuel system. Using Cat ET set the "Fuel Injection Enable Status" in the configuration screen to "Enabled". Proceed to Test Step 12.
12. Perform a "Fuel System Functional Test" A. Remove the accumulator leak detection plugs. B. Remove all the accumulator leak detection plugs. C. Turn the keyswitch to the ON position. D. Connect Cat ET. \E. Start the engine. F. Perform the "Fuel System Functional Test". G. Once the test has completed, turn the keyswitch to the OFF position to allow the pump diagnostics to run. H. Wait for 30 seconds once the engine has stopped, and then Turn the keyswitch to the ON position. I. Connect Cat ET. J. Check for active diagnostic codes.	Test Successful	Result: The "Fuel System Functional Test" passed successfully and there are no active codes. Reinstall the accumulator leak detection plugs. Reinstall the accumulator leak detection plugs. 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).