Removal/Installation
- Refer to the Throttle Body Assy Disassembly/Assembly.
Audible Inspection
- Start the engine.
- Apply the tip of a screwdriver [A] to the injector [B]. Put the grip end onto your ear, and listen whether the injector is clicking or not.
A sound scope [C] can also be used.
- Do the same for the other injectors.
If all the injectors click at a regular intervals, the injectors are good. The trouble may be related to the fuel line, requiring fuel pressure inspection (See Fuel Pressure Inspection).
The click interval becomes shorter as the engine speed rises.
If any injector(s) doesn't click, the DFI circuit or the injector is suspect. Perform "Fuel Injector Power Source Voltage Inspection", first.
Fuel Injector Power Source Voltage Inspection
- Disconnect the injector connector [A] and connect the insulated auxiliary leads [B] between injector [C] and injector connector.
Caution: Do not short each terminals.
- Connect a digital meter [D] as shown.
Injector Power Source Voltage
Connections to injector
For Injector #1 [E]:
- Meter (+) → W/R lead
- Meter (-) → Battery (—) Terminal
For Injector #2 [F]:
- Meter (+) → W/R lead
- Meter (-) → Battery (—) Terminal
- Measure the power source voltage with the engine stopped, and with the connector joined.
- Turn the engine stop switch to run position.
- Turn the ignition switch ON.
Power Source Voltage at Injector
Standard: Battery Voltage for 3 second, and then 0 V
- Turn the ignition switch OFF.
If the meter doesn't read as specified, check the following. Main Fuse 30 A (See Fuse Inspection in the Electrical System chapter).
Fuel Pump Relay (See Relay Circuit Inspection in the Electrical System chapter).
Power Source Wiring (see wiring diagram below).
To check the W/R leads between the injector connector and the fuel pump relay, remove the reply box (see Reply Box Removal in the Electrical System chapter).
If the power source voltage is normal, check the output voltage of the injectors.
Fuel Injector Output Voltage Inspection
- Disconnect the injector connector [A] and connect the insulated auxiliary leads [B] between injector [C] and injector connector.
Caution: Do not short each terminals.
- Connect a digital meter [D] as shown.
Injector Output Voltage
Connections to injector
For Injector #1 [E]:
- Meter (+) → BL/R lead
- Meter (-) → Battery (—) Terminal
For Injector #2 [F]:
- Meter (+) → BL/G lead
- Meter (-) → Battery (—) Terminal
- Turn the engine stop switch to run position.
- Turn the ignition switch ON.
Output Voltage at Injector
Standard: Battery Voltage for 3 second, and then 0 V
- Turn the ignition switch OFF.
If the output voltage is normal, perform "Injector Signal Test".
If the output voltage is out of the standard, remove the ECU (See ECU Removal/Installation), and check the injector wiring for continuity.
Injector Wiring Inspection
- Terminal 42 → Injector #1 Terminal (BL/R)
- Terminal 41 → Injector #2 Terminal (BL/G)
If the wiring is good, inspect the resistance of the injectors (See Injector Resistance Inspection).
Injector Signal Test
- Prepare two test light sets with terminals as shown.
Rating of Bulb [A]: 12 V x 3-3.4 W
Terminal Width [B]: 1.8 mm (0.071 in.)
Terminal Thickness [C]: 0.8 mm (0.031 in.)
Caution: Do not use larger terminals than specified above. A larger terminal could damage the injector main harness connector, leading to harness repair or replacement. Be sure to connect bulbs in series. The bulb works as a current limiter to protect the solenoid in the injector from excessive current.
Remove:
- Fuel Tank (See Fuel Tank Removal)
- Air Cleaner Housing (See Air Cleaner Housing Removal).
- Disconnect the connectors for injector [A].
- Connect each test light set [B] to the injector sub harness connector [C].
- Turn the ignition switch ON.
- While cranking the engine with the starter motor, watch the test lights.
If the test lights flicker at regular intervals, the injector circuit in the ECU, and the wiring are good. Perform the "Injector Resistance Inspection".
Injector signals can be also confirmed by connecting the hand tester (x AC 10 V ) instead of the test light set to the injector main harness connector. Crank the engine with the starter motor, and check to see if the hand oscillates at regular intervals.
Special Tool - Hand Tester: 57001-1394
If the test light doesn't flicker (or the tester needle doesn't oscillates), check the wiring and connectors again.
If the wiring is good, replace the ECU (See ECU) Re-moval/Installation).
Injector Resistance Inspection
Remove:
- Fuel Tank (See Fuel Tank Removal)
- Air Cleaner Housing (See Air Cleaner Housing Removal)
- Disconnect the connector from the injector [A].
- Measure the injector resistance with the hand tester [B].
Special Tool - Hand Tester: 57001-1394
Injector Resistance
Connections to Injector Connector
Meter (+) Meter (-)
- #1: W/R ←→ BL/R Terminal
- #2: W/R ←→ BL/G Terminal
Standard: About 11.7-12.3 Q at 20°C (68°F)
If the reading is out of the range, perform the "Injector Unit Test".
If the reading is normal, perform the "Injector Unit Test" for confirmation.
Injector Unit Test
- Use two leads [A] and the same test light set [B] as in "Injector Signal Test".
Rating of Bulb [C]: 12 V x (3-3.4) W
12 V Battery [D]
Caution: Be sure to connect the bulb in series. The bulb works as a current limiter to protect the solenoid in the injector from excessive current.
- Connect the test light set to the injector [E] as shown.
- Open and connect [F] the end of the lead to the battery (-) terminal repeatedly. The injector should click.
If the injector does not click, replace the injector.
Injector Fuel Line Inspection
- Remove the fuel tank (See Fuel Tank Removal).
- Be sure to place a piece of cloth around the fuel hose joint and the delivery pipe.
- Insert a minus screwdriver [A] into the slit on the joint lock [B].
- Turn the driver to disconnect the joint lock.
- Pull the fuel hose joint [C] out of the delivery pipe.
- Check the injector fuel line for leakage as follows.
Connect a commercially available vacuum/pressure pump [A] to the nipple of the delivery pipe [B] with a high-pressure fuel hose [C] (both ends connected with the clamps [D]) as shown.
Torque - Fuel Hose Clamp Screws: 1.5 №m (0.15 kgf·m, 13 in4b)
Apply soap and water solution to the areas [E] as shown. OWatching the pressure gauge, squeeze the pump lever [F], and build up the pressure until the pressure reaches the maximum pressure.
Injector Fuel Line Maximum Pressure
Standard: 333 kPa (3.4 kgf/cm², 48 psi)
Caution: During pressure testing, do not exceed the maximum pressure for which the system is designed.
- Watch the gauge for at least 6 seconds.
If the pressure holds steady, the system is good.
If the pressure drops at once or if bubbles are found in the area, the line is leaking. Replace the delivery pipe, injectors and related parts.
Repeat the leak test, and check the fuel line for no leakage.
- Run the hoses correctly (See Cable, Wire, and Hose Routing section in the Appendix chapter).
Fuel Injector Circuit
1. ECU; 2. Fuel Injectors; 3. Water-proof Joint C; 4. Engine Stop Switch; 5. Ignition Switch; 6. Water-proof Joint A; 7. ECU Fuse 15A; 8. Ignition Fuse 10 A; 9. ECU Main Relay; 10. Fuel Pump Relay; 11. Main Fuse 30 A; 12. Battery 12 V10 Ah; 13. Frame Ground; 14. Joint Connector