C7.1 Engines Caterpillar

Engine Cranks but Does Not Start

Usage:

C7.1 881

Probable Causes

Diagnostic codes
Visible faults
Air intake and exhaust system
Speed/timing sensor
Low-pressure fuel system
Transfer Pump Inlet Regulator (TPIR)
EFLP flow rate
Return fuel lines
High-pressure fuel system
Starting aids
Low compression (cylinder pressure)

Table 1
Troubleshooting Test Steps	Values	Results
1. Diagnostic Codes A. Download the Warranty Report and the Product Status Report with Histograms before performing any troubleshooting or clearing any diagnostic codes. Note: The downloaded information will be required by the Dealer Solutions Network (DSN) if troubleshooting assistance is needed. B. Use the electronic service tool to check for active or logged codes.	Diagnostic codes	Result: A diagnostic code is present. Repair: Troubleshoot the code and then reset the histogram. Result: A diagnostic code is not present. Proceed to Test Step 2.
2. Visible Faults A. Check that the fuel supply valve (if equipped) is in the OPEN position. B. Check for the correct level of fuel, oil, and coolant. C. Check for water in the primary fuel filter/water separator. D. If the ambient temperature is below 0 °C (32 °F), check the specification of engine oil and oil for the machine. E. Visually inspect the engine for the following faults: · Missing components · Damaged components · Damaged electrical cables or loose electrical cables · Oil leaks · Fuel leaks · All fuel filters are correctly installed. F. Check that the battery voltage is correct. G. Use the electronic service tool to check the average cranking speed of the engine.	Visible faults	Result: The fuel supply valve (if equipped) is not in the OPEN position. Repair: Move the fuel supply valve to the OPEN position. Result: The level of fuel, oil, or coolant is not correct. Repair: Replenish any fluids with an incorrect level. Result: Water is present in the primary fuel filter/water separator. Repair: Drain any water from the primary fuel filter/water separator. Result: The correct specification of engine oil and oil for the machine is not in use. Repair: Replenish the system with oil of the correct specification for the ambient conditions. Result: Battery voltage is low. Repair: Check the batteries. Refer to Troubleshooting, "Battery Problem". Result: The cranking speed is less than 150 rpm. Repair: Investigate the cause of the low cranking speed and rectify, as necessary. Note: If the DPF frequently collects excessive soot prior to this fault, there may be a faulty cylinder in the engine. Proceed to Test Step 12. Result: All checks are OK. Proceed to Test Step 3.
3. Air Intake and Exhaust System A. Check the air filter restriction indicator, if equipped. B. Check the air intake and exhaust systems for the following defects: · Blockages · Restrictions · Damage to lines or hoses	Air and Exhaust System restrictions	Result: The air filter is restricted. Repair: Replace the air filter. Result: There are system restrictions. Refer to Systems Operation/Testing and Adjusting, "Air Inlet and Exhaust System" for additional information on the air inlet and exhaust systems. Result: The air intake and exhaust system is OK. Proceed to Test Step 4.
4. Speed/Timing Sensors A. Crank the engine and observe the engine speed on the electronic service tool status screen. Refer to Troubleshooting, "Speed/Timing - Test" for additional information. Note: Upon initial cranking, the status for engine speed may indicate that the engine speed signal is abnormal. This message will be replaced with an engine speed once the ECM is able to calculate a speed from the signal.	Speed/timing sensor	Result: The speed/timing sensors are not operating correctly. Repair: Test the speed/timing sensors. Refer to Troubleshooting, "Speed/Timing - Test". Result: The speed/timing sensors are operating correctly. Proceed to Test Step 5.
5. Low-Pressure Fuel System A. Visually check the fuel tank for fuel. Note: The fuel gauge may be faulty. B. If the temperature is below 0 °C (32 °F), check for solidified fuel (wax). C. Check the primary filter/water separator for water in the fuel. D. Check for fuel supply lines that are restricted or not correctly installed. E. Replace the in-line fuel filter that is installed upstream of the Electric Fuel Lift Pump (EFLP). F. Check that the EFLP is operating correctly. G. Check for air in the fuel system and that the fuel system is primed. H. Check the diesel fuel for contamination. Refer to Systems Operation, Testing, and Adjusting, "Fuel Quality - Test".	Low-pressure fuel system	Result: The fuel tank level is low. Repair: Fill the fuel tank. Result: The fuel contains solidified wax. Repair: Replace the fuel with fuel of the correct specification for the ambient conditions. Result: There are fuel supply lines that are restricted or not correctly installed. Repair: Install the fuel lines correctly. Replace any damaged or restricted fuel lines. Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information. Result: The EFLP is not operating correctly. Investigate the fault with the EFLP. Refer to Troubleshooting, "Relay - Test". Result: There is air in the fuel system. Repair: Prime the fuel system. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime". Result: The diesel fuel is contaminated. Repair: Drain the fuel tank and the fuel system. Replace the primary fuel filter and the secondary fuel filters. Refer to the Operation and Maintenance Manual for further information. Fill and prime the fuel system with fuel of the correct specification. Refer to Systems Operation, Testing, and Adjusting, "Fuel System - Prime". Result: The low-pressure fuel system is OK. Proceed to Test Step 6.

Table 2
Troubleshooting Test Steps	Values	Results
6. Transfer Pump Inlet Regulator (TPIR) Flow Test Refer to Illustration 1. A. Disconnect the TPIR return line from the drain port on the TPIR. Install a suitable blanking cap on the open port in the TPIR return line. B. Connect a temporary drain line to the drain port on the TPIR. C. Place the end of the temporary drain line into a suitable calibrated container. D. With the isolator switch in the ON position but the engine not running, use a suitable multimeter to measure the input voltage to the EFLP. Record the reading. E. With the isolator switch in the ON position but the engine not running, measure the fuel flow from the temporary drain line. F. Refer to Illustration 2 or 3 for the minimum acceptable flow rate. G. Remove the temporary drain line from the drain port on the TPIR. Connect the TPIR return line to the TPIR.	TPIR flow rate	Result: The fuel flow is greater than the minimum limit. Proceed to Test Step 8. Result: The fuel flow is less than the minimum limit. Proceed to Test Step 7.

Table 3
Troubleshooting Test Steps	Values	Results
7. EFLP Flow Test at the Primary Fuel Filter Inlet A. Make sure the keyswitch is in the OFF position. B. Disconnect the fuel inlet connection from the primary fuel filter head. C. Install a suitable blank on the fuel inlet port on the primary fuel filter head. D. Place the open end of the fuel inlet line in a suitable calibrated container. E. With the keyswitch in the ON position, measure the input voltage at the EFLP. Record the result. F. With the keyswitch in the ON position, measure the flow from the fuel inlet line. Record the result. G. Check the recorded voltage and fuel flow on the graph in Illustration 4 or 5.	EFLP flow	Result: The fuel flow is below the minimum value for the recorded voltage. Repair: Replace the EFLP. Refer to Disassembly and Assembly, "Fuel Priming Pump - Remove and Install ". Result: The fuel flow is above the minimum value for the recorded voltage. Proceed to Test Step 8.
8. Check the Return Fuel Lines A. Make sure that the TPIR return line is not blocked or kinked. B. If the TPIR return line is clear, confirm that the Electric Fuel Lift Pump (EFLP) is operating. Make sure that fuel lines between the EFLP and the TPIR are not blocked or kinked.	Return lines	Result: The TPIR return line or the fuel lines between the EFLP and the TPIR are blocked or kinked. Repair: Clear or replace the blocked line. Result: The TPIR return line and the fuel lines between the EFLP and the TPIR are clear. Repair: Replace the EFLP. If the fault is still present, proceed to Test Step 9.

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.

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NOTICE

Contact with high-pressure fuel may cause personal injury or death. Wait 10 minutes after the engine has stopped to allow fuel pressure to purge before any service or repair is performed on the engine fuel lines.

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Table 4
Troubleshooting Test Steps	Values	Results
9. High-Pressure Fuel System A. Use the electronic service tool to check the absolute fuel rail pressure while the engine is cranking at a minimum speed of 150 rpm.	High-pressure fuel system	Result: The absolute fuel rail pressure is less than 25 MPa (3625 psi). Repair: Check for fuel leaks in the high-pressure fuel system. Rectify any fuel leaks and then recheck the pressure in the fuel rail. Use the electronic service tool to perform a solenoid test on the fuel injection pump. Refer to Troubleshooting, "Solenoid Valve - Test". Check the Pressure Limiting Valve (PLV) in the fuel rail for leakage. If the valve is leaking, replace the valve and recheck the pressure in the fuel rail. Check for fuel in the engine oil system. If fuel is suspected in the oil system, take an engine oil sample for analysis. Refer to the Operation and Maintenance Manual, "Engine Oil Sample - Obtain". If the analysis confirms that there is fuel in the engine oil system, investigate the cause. Result: The absolute fuel rail pressure is greater than 25 MPa (3625 psi). Use the electronic service tool to make sure that the status of the electronic unit injectors is not "Disabled". If the injectors are disabled but the injectors have not been intentionally disabled, proceed to Test Step 11. Use the electronic service tool to perform an injector solenoid test. Refer to Troubleshooting, "Injector Solenoid - Test". If the engine will not start, proceed to Test Step 10.
10. Electronic Control Module (ECM) A. Make sure that the latest flash file for the application is installed in the ECM.	ECM	Result: Installation of the latest flash file does not eliminate the fault. Repair: Contact the Dealer Solutions Network (DSN). Note: This consultation can greatly reduce the repair time. If the DSN recommends the use of a test ECM, install a test ECM. Refer to Troubleshooting, "ECM - Replace". Attempt to start the engine. If the engine will not start, install the original ECM and then proceed to Test Step 11. If the engine starts normally, reconnect the suspect ECM and then verify that the fault returns when the suspect ECM is installed. If the engine will not start with the suspect ECM, replace the ECM and then check that the engine starts normally.
11. High-Pressure Fuel Pump A. Check the timing of the high-pressure fuel pump. Refer to Systems Operation, Testing, and Adjusting, "Fuel Injection Timing - Check".	HP fuel pump	Result: The timing of the high-pressure fuel pump is incorrect. Repair: Correct the timing of the high-pressure fuel pump. Refer to Disassembly and Assembly, "Fuel Injection Pump - Remove" and Disassembly and Assembly, "Fuel Injection Pump - Install". With the high-pressure fuel pump correctly timed, check that the engine starts normally. If the engine will not start, proceed to Test Step 12. Result: The timing of the high-pressure fuel pump is correct. Repair: Replace the high-pressure fuel pump. Refer to Disassembly and Assembly, "Fuel Injection Pump - Remove" and Disassembly and Assembly, "Fuel Injection Pump - Install". Check that the engine starts normally. If the engine will not start, proceed to Test Step 12.
12. Starting Aids A. Check the operation of the glow plugs. Refer to Troubleshooting, "Glow Plug Starting Aid - Test". B. If equipped, check the operation of the ether starting aid. Refer to Troubleshooting, "Ether Starting Aid - Test".	Starting aids	Result: One or more of the glow plugs are faulty. Repair: Replace any faulty glow plugs. Refer to Disassembly and Assembly, "Glow Plug - Remove and Install". Check that the engine starts normally. If the engine will not start, proceed to Test Step 13. Result: The ether starting aid is faulty. Repair: Diagnose the ether system. Refer to Troubleshooting, "Ether Starting Aid - Test". Check that the engine starts normally. If the engine will not start, proceed to Test Step 13.
13. Low Compression (Cylinder Pressure) A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test ".	Cylinder compression	Result: The results of the compression test are outside the specifications. Repair: Investigate the cause and rectify any faults. Note: Possible causes of low compression are shown in the following list: · Loose glow plugs · Faulty piston · Faulty piston rings · Worn cylinder bores · Worn valves · Faulty cylinder head gasket · Damaged cylinder head Result: The results of the compression test are OK. Contact the Dealer Solutions Network (DSN).