Fuel Injector: Testing and Inspection

INSPECTION








Using Scan tool

Check Item: Injector.
Data Display: Drive time.
Check Conditions: Engine cranking.
- With coolant temperature 0°C (32°F) injector time approximately 17 ms.
- With coolant temperature 20°C (68°F) injector time approximately 35 ms.
- With coolant temperature 80°C (176°F) injector time approximately 8.5 ms.

Check Item: Injector.
Data Display: Drive time.
Check Conditions: Engine coolant temperature 8O to 95°C (176 to 2O5°F), lamps, electric cooling fan, accessory units all OFF, Transaxle Neutral (P range for vehicle with A/T), Steering wheel Neutral,
- At 75O rpm (Idle) should read 2.2 - 2.9 ms.
- At 2,000 rpm should read 1.8 - 2.6 ms.
- Rapid racing should increase.

Check Item: Injector.
Item number: 1 through 4. Injector shut off.
Check Conditions: Engine idling after warm-up (Shut off the injectors in sequence after engine warm-up, check the idling condition)
- Idle should become unstable as injector shut off.

NOTE: When engine coolant temperature is lower than 0°C (32°F), the Engine Control Module 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.

Actuator Inspection

SCAN TOOL CHECK

Using a scan tool, check as described below.
- Cut off the Fuel Injectors in sequence.
- Check the operation time of the Injectors.

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 vibrations are felt, check the wiring connector, Injector, or injection signal from Engine Control Module.

RESISTANCE MEASUREMENT BETWEEN TERMINALS
1. Disconnect the connector at the Injector.





2. Measure the resistance between terminals.

Resistance: 13 - 16 Ohms at 20°C (68°F).

3. Connect the connector to the injector.

Harness Inspection Procedure





1. Measure the power supply voltage to the Injector.
- Connector disconnected.
- Ignition switch ON.
- Voltage should read system voltage.

If OK - go to step 2.
If not OK - Repair the harness (A B C D 2 - MFI Control relay) Check the power supply.





2. Check for an open circuit, or a short circuit to ground between the Engine Control Module and the Injector.
- Engine Control Module connector disconnected.
- Injector connector disconnected.

If OK - END.
If not OK - Repair the harness. (A B C D 1 - C50-4 12,13,25,26)

Troubleshooting Hints
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, then check the following;
- Faulty power supply circuit to the Engine Control Module, faulty ground circuit.
- Faulty MFI Control Relay.
- Faulty Crankshaft Position Sensor, Camshaft Position Sensor.
3. If there is any cylinder whose idle state remains unchanged when the fuel injection of injectors is cut one after another during idling, check for the following items about such 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 Exhaust Gas Recirculation Valve seating.