Fuel Injector

FUEL INJECTOR




The injectors inject fuel according to a signal coming from the ECU. The amount of fuel injected by the injectors is determined by the time during which the solenoid valve is energized. The amount of time the solenoid value is energized is determined by the pulse width of the signal from the ECU.

Circuit Diagram:

Harness Inspection Procedures:

Using Hi-Scan:

INJECTOR CHECKING

NOTE:
- The injector drive time is when the supply voltage is 11 V and the cranking speed is less than 250 rpm.
- When engine coolant temperature is lower than 0 °C (32 °F), the ECU fires all four cylinders simultaneously
- When the vehicle is new (within initial operation of about 500 km [300 miles]), the injector drive time may be about 10% longer.

USING STETHOSCOPE AND VOLTMETER

Operation Sound Check




1. Using a stethoscope, check the injectors for a clicking sound at idle. Check that the sound is produced at shorter intervals as the engine speed increases.

NOTE: Ensure that the sound from an adjacent injector is not being transmitted along the delivery pipe to an inoperative injector




2. If a stethoscope is not available, check the injector operation with your finger. If no vibration is felt, check the wiring connector, injector or injection signal from the ECU.

3. Disconnect the connector at the injector.
4. Measure the resistance between terminals.

Standard value : 13.8 - 15.2 Ohm [at 20 °C (68 °F)]




5. Re-connect the connector to the injector.

TROUBLESHOOTING HINTS

1. If the engine is hard to start when hot, check for fuel pressure and injector leaks.
2. If the injectors do not operate when the engine is cranked, then check the followings:
- Defective power supply circuit to the ECU, faulty ground circuit
- Defective control relay
- Defective crankshaft position (CKP) sensor or camshaft position (TDC) sensor

3. If there is any cylinder whose idle state remains unchanged when the fuel injectors are cut one after another during idling, check for the following items about that a cylinder.
- Injector and harness
- Ignition plug and high tension cable
- Compression pressure

4. If the injection system is OK but the injector drive time is out of specification, check for the following items.
- Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
- Loose EGR valve seating.