Fuel Injector: Testing and Inspection

FUEL INJECTOR
The injectors inject fuel according to a signal coming from the ECM. The amount of fuel injected by the injectors is determined by the time during which the solenoid valve is energized.

NOTE:
1. If the engine is hard to start when hot, check for fuel pressure and injector leaks.
2. If the injector does not operate when the engine is cranked, check for the following:
- Faulty power supply circuit to the ECM; faulty ground circuit
- Faulty control relay
- Faulty Crankshaft Position (CKP) sensor, camshaft position (CMP) sensor.
3. If any cylinder's idle state remains unchanged when the fuel injection of each injector is cut one after another during idling, check the following:
- 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:
- Injector and harness
- Poor combustion in the cylinder (faulty ignition plug, ignition coil, compression pressure, etc.)
- Loose EGR valve seating










Using GST

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







HARNESS INSPECTION PROCEDURES










Actuator Inspection

Operational Check
Using a GST, check as described below.
- Cut off the fuel injectors in sequence.
- Check the operation time of the injectors.

Operational 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 transmiffed along the delivery pipe to an inoperative injector.

2. If a stethoscope is not available, check the injector operation with your finger. If no vibrations are felt, check the wiring connector, injector, or injection signal from ECM.
Resistance Measurement Between Terminals
3. Disconnect the connector at the injector.
4. Measure the resistance between terminals.

Standard value 13-16 ohms @ 20°C (68°F)

5. Connect the connector to the injector.