Fuel Injector: Testing and Inspection

Fuel Injector Circuit Check

Component Description

The fuel injector is a small, precise solenoid valve. When the ECM supplies a ground to the fuel injector, the coil in the fuel injector is energized. The energized coil pulls the ball valve back and allows fuel to flow through the fuel injector into the intake manifold. The amount of fuel injected depends upon the injection pulse duration. Pulse duration is the length of time the fuel injector remains open. The ECM controls the injection pulse duration based on engine fuel needs.





Diagnosis Procedure

1. INSPECTION START

Turn ignition switch to START.

Are any cylinders ignited?

Yes or No
Yes (With SDT)
GO TO 2.
Yes (Without SDT)
GO TO 3.
No
ERROR! Unknown action!GO TO 7.

2. CHECK OVERALL FUNCTION

With SDT
1 Start engine.
2 Perform "POWER BALANCE" in "Active test" mode with SDT.
3 Make sure that each circuit produces a momentary engine speed drop.

OK or NG
OK
INSPECTION END
NG
GO TO 7.

3. CHECK FUNCTION OF FUEL INJECTOR-I

Without SDT
1 Stop engine.
2 Disconnect harness connector F44 (3), F201 (1)











3 Turn ignition switch ON.
4 Check voltage between harness connector F44 terminal 3 and ground with SDT or tester.











5 Turn ignition switch OFF.
6 Disconnect ECM harness connector.
7 Check harness continuity between harness connector F44 and ECM as follows.
Refer to Wiring Diagram.










8 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 5.
NG
GO TO 4.

4. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E2, F32
- IPDM E/R harness connector E119
- 15 A fuse (No.55)
- Harness for open or short between harness connector F44 and fuse
- Harness for open or short between harness connector F201 and fuel injector


Repair open circuit or short to ground or short to power in harness or connectors.

5. CHECK FUNCTION OF FUEL INJECTOR-II

Provide battery voltage between harness connector F201 as follows and then interrupt it. Listen to each fuel injector operating sound.















OK or NG
OK
GO TO 6.
NG
GO TO 7.

6. CHECK FUNCTION OF FUEL INJECTOR-III

1 Reconnect all harness connector disconnected.
2 Start engine.
3 Listen to fuel injectors No. 2, No. 4, No.6 operating sound.











OK or NG
OK
INSPECTION END
NG
GO TO 7.

7. CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT

1 Turn ignition switch OFF.
2 Disconnect fuel injector harness connector.





3 Turn ignition switch ON.
4 Check voltage between fuel injector terminal 1 and ground with SDT or tester.











OK or NG
OK
GO TO 9.
NG
GO TO 8.

8. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors E2, F32
- Harness connectors F44, F201
- IPDM E/R harness connector E119
- 15 A fuse (No.55)
- Harness for open or short between fuel injector and fuse


Repair harness or connectors.

9. CHECK FUEL INJECTOR OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1 Turn ignition switch OFF.
2 Disconnect ECM harness connector.
3 Check harness continuity between fuel injector terminal 2 and ECM terminals 21, 22, 23, 40, 41, 42.
Refer to Wiring Diagram.






4 Also check harness for short to ground and short to power.

OK or NG
OK
GO TO 11.
NG
GO TO 10.

10. DETECT MALFUNCTIONING PART

Check the following.
- Harness connectors F201, F44
- Harness for open or short between fuel injector and ECM


Repair open circuit or short to ground or short to power in harness or connectors.

11. CHECK FUEL INJECTOR

Refer to "Component Inspection".

OK or NG
OK
GO TO 12.
NG
Replace fuel injector. Refer to [Fuel Injector and Fuel Tube: Exploded View [VQ40DE] Exploded View ].

12. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.


INSPECTION END

Component Inspection

Fuel Injector

1) Disconnect injector harness connector.
2) Check resistance between terminals as shown in the figure.