FUSO 4M4 – FUEL AND ENGINE CONTROL – ON-VEHICLE INSPECTION AND ADJUSTMENT

1. Inspecting and Adjusting No-load Minimum and Maximum Speeds

[Work before inspection]
• Before starting the inspection and adjustment, carry out the following preparatory steps:
• Warm up the engine until the engine coolant temperature is approximately 80 to 95°C; (Check by Multi-Use Tester service data “13: Water temperature”.)
• Turn off all lamps and accessories;
• Place the transmission shift lever into the N position;
• Set the steering wheel at the straight-ahead position; and
• Attach a tachometer.

[Inspection]
(1) No-load minimum speed
• Without pressing the accelerator pedal, measure the engine speed.
• If the measurement is not within the standard value range, inspect the accelerator position sensor. (See “ENGINE CONTROL”.)
• If no defects are evident during the above inspection, check diagnosis code from engine-electronic control unit or fuel system.

(2) No-load maximum speed
• Press the accelerator pedal as far as it will go.
• With the accelerator pedal touching the lever stopper, measure the engine speed.
• If the measurement is not within the standard value range, inspect the accelerator position sensor. (See “ACCELERATOR PEDAL”.)
• If no defects are evident during the above inspection, check diagnosis code from engine-electronic control unit or fuel system.

2. Air-bleeding of Fuel System

• Loosen one of the air vent plugs on the fuel filter.
• Move the priming pump up and down to pump out the fuel.
• Continue operating the priming pump until the fuel flowing out of the plug is free of air bubbles.
• When no more air bubbles are evident, tighten the air vent plug to the specified torque.
• Feed the fuel some more by operating the priming pump further until a strong resistance is felt.
• When the fuel temperature is low, you may not feel the resistance. Be sure to operate the priming pump several times even in such a case.
• Wipe up any spilled fuel and start the engine.
• Check that there is no fuel leakage.

3. Fuel Filter Replacement

[Removal]
• Loosen the water separator sensor and drain fuel from the case.
• Remove the case using

[Installation]
• Clean the O-ring mounting surface of the fuel filter head and the O-ring groove of the case.

• Replace the filter element and O-ring with new one.
• Apply a thin coat of engine oil to the O-ring, and install it on the case and water separator sensor.

• Use to tighten the case to the specified torque.
• Install the water separator sensor, and then air-bleed the fuel system.
• Start the engine, and check that there is no fuel leakage.
• Reinstall the fuel filter if there is any leakage.

4. Registration of Vehicle Identification Number (VIN)
• A vehicle identification number (VIN) must be written (registered) to the engine electronic control unit after:
– The current engine electronic control unit is replaced with a new one.
– The current engine electronic control unit is replaced with one that has been used on another vehicle.
• For the details of the replace work, consult your nearest MITSUBISHI FUSO distributor or dealer.

 

 

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