Fuel system

TROUBLESHOOTING

When troubleshooting the engine, start by checking the operation and inspecting the main systems. If the engine runs poorly, the idle speed is unstable, or acceleration is insufficient, check the following main systems:

1. Electrical power supply:
– battery;
– fusible link;
– fuse.

2. Ground connections

3. Fuel supply:
– fuel line;
– fuel filter;
– fuel pump.

4. Ignition system:
– spark plug;
– high-tension leads;
– ignition coil.

5. Emission control system:
– crankcase ventilation system;
– vacuum leak.

6. Other:
– ignition timing;
– idle speed.

MFI system malfunctions are often caused by poor connections in the wiring harness connectors. Therefore, check that all connectors are securely connected.

IDLE SPEED INSPECTION

Before checking the idle speed, make sure that the spark plugs, fuel injectors, idle speed control (ISC) motor, compression, etc. are in good condition.

Inspection conditions

PROCEDURE

1. Warm up the engine until the coolant temperature reaches 80–95 °C.
2. Turn off the headlights, parking lights, radiator fan, and all electrical loads.
3. Place the transmission in Neutral.
4. Set the steering wheel in the straight-ahead position.

Inspection

PROCEDURE

1. Connect a tachometer to the primary side of the ignition coil, or connect a scan tool to the diagnostic connector.
2. Start the engine and let it idle.
3. Raise the engine speed to 2000–3000 min⁻¹ for no more than 5 seconds, then let it idle for 2 minutes.
4. Read the idle speed on the tachometer.