This article introduces how to solve the problem of Carter 325C excavator cranking and starting the engine, but the engine does not start.

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        (1) Possible reasons. 

 1) Diagnostic code. 

 2) Event code.  

3)ECM power supply. 

 4) Engine oil level.

  5) Start the auxiliary device.  

6) Engine stop switch. 

 7) Engine speed/timing. 

 8)Injection driving pressure. 9) Single fuel injector.  

10) Fuel supply. 

 11) Combustion failure.

(2) Recommended measures. 

 1) Diagnostic codes, event codes and ECM power. Certain diagnostic codes and/or event codes will 

prevent the engine from starting. Connect to Caterpillar Electronic Technologies (Cat ET) and check 

for 

current and/or logged codes. Before continuing with this procedure, troubleshoot and troubleshoot any 

existing code. Note: If the Cat ET cannot communicate with the ECM, the problem is most likely with 

the power supply to the ECM. Please refer to "Power Supply Circuit "Testing" section. 

 2) Oil level. Check the engine oil level. Add engine oil if necessary. NOTE: Engine oil supplies the 

injection drive pressure circuit. Need dimension Maintaining the correct engine oil level allows fuel 

injection. 

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 3) Start the auxiliary device.

  ① Inlet air heater. Make sure the intake air heater is set to the ON position. 

 ②Engine stop switch (if equipped). The engine stop switch should be in the OFF position. Verify the 

status of the parking switch with Cat ET state. When parking, the key switch should be turned to the 

OFF position for at least 15 seconds before starting the engine again. NOTE: If Cat ET is unable to 

communicate with the ECM, the problem is most likely with the power supply to the ECM, see the 

"Testing the Power Supply Circuit" section. 

 4) Engine speed/timing. ① Crank the engine and observe the engine speed on the Cat ET status screen.

  If the Cat ET displays Or/min, see the Testing of the Engine Speed/Timing Sensor Circuit section.

  Note: When cranking for the first time, the engine status may show that the engine speed signal is 

abnormal. Once the ECM can get the signal from The engine speed is calculated and this information is 

replaced by the engine speed. 

 ② Confirm that the timing reference gear is installed correctly. If the gears are installed backwards, the 

engine will not start. Check alignment between crankshaft and camshaft drive gear bit is correct. If 

necessary, correct positioning and/or replace drive gear. 

 5)Injection driving pressure. 

 ①Crank the engine and monitor the injection drive pressure and the output pressure of the injection 

drive pressure control valve. If the pressure output is not less than 6MPa, high-pressure oil system The 

system is running normally. 

 ② If the displayed pressure is higher than the current pressure, disconnect the injection drive pressure 

sensor and try to start the engine. If the engine starts, refer to See the "Testing the Injection Drive 

Pressure Sensor" section. 

 6) Single fuel injector. Perform the "Injector Solenoid Test" on the Cat ET to determine if all injector 

solenoids have been energized.  

7) Fuel supply. 

 ①Visually check the fuel level. Don't rely solely on the fuel gauge. Add fuel if necessary. If the engine 

runs out of fuel, the air must be Bleed from fuel system.

  ② Check the fuel lines for the following problems: throttling, collapsed and pinched lines. If the fuel 

lines are faulty, repair and/or replace these lines. 

 ③ Check whether there are any foreign objects in the fuel tank. Foreign objects will block the fuel 

supply. 

 ④ If any of the procedures of replacing the fuel filter, repairing the low-pressure fuel supply circuit, 

and replacing the unit injector have been performed, check whether there is air in the low-pressure fuel 

supply system. Note: The sight glass in the low-pressure fuel supply line is helpful in diagnosing the 

presence of air in the fuel. Note: Do not crank and start the engine continuously. More than 30s. Before 

cranking the engine again, allow the starter to cool down for 2 minutes. 

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 ⑤ Bleed the air out of the low-pressure fuel supply circuit.  

⑥ Check the fuel quality. If the temperature is below 0°C, check for solidified fuel (wax). 

 ⑦ When cranking the engine, check the fuel pressure after the fuel filter. If fuel pressure is low, replace

 the fuel filter. If the fuel pressure is still is low, check the following items: fuel transfer pump, fuel 

transfer pump coupling and fuel pressure regulating valve