Nissan Altima 2007-2012 Service Manual: Fuel injector

Description

The fuel injector is a small, precise solenoid valve. When the ECM supplies a ground to the fuel injector circuit, the coil in the fuel injector is energized. The energized coil pulls the ball valve back and allows fuel to flow via 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.

Component Function Check

1.INSPECTION START

Turn ignition switch to START.

Are any cylinders ignited? YES >> GO TO 2.

NO >> Go to EC-1483, "Diagnosis Procedure".

2.CHECK FUEL INJECTOR FUNCTION

1. Start engine.

2. Perform “POWER BALANCE” in “ACTIVE TEST” mode with CONSULT-III.

3. Check that each circuit produces a momentary engine speed drop.

1. Start engine.

2. Listen to each fuel injector operating sound.

Clicking sound should be heard.

Is the inspection result normal? YES >> INSPECTION END

NO >> Go to EC-1483, "Diagnosis Procedure".

Diagnosis Procedure

1.CHECK FUEL INJECTOR POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect fuel injector harness connector.

3. Turn ignition switch ON.

4. Check the voltage between fuel injector harness connector and ground.

Is the inspection result normal? YES >> GO TO 3.

NO >> GO TO 2.

2.DETECT MALFUNCTIONING PART

Check the following.

• 10 A fuse (No. 35) • IPDM E/R harness connector E10

• Harness for open or short between fuel injector and IPDM E/R

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

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

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check the continuity between fuel injector harness connector and ECM harness connector.

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

Is the inspection result normal? YES >> GO TO 4.

NO >> Repair open circuit, short to ground or short to power in harness or connectors.

4.CHECK FUEL INJECTOR

Refer to EC-1485, "Component Inspection".

Is the inspection result normal? YES >> GO TO 5.

NO >> Replace malfunctioning fuel injector.

5.CHECK INTERMITTENT INCIDENT

Refer to GI-42, "Intermittent Incident".

Is the inspection result normal? YES >> Replace IPDM E/R.

NO >> INSPECTION END

Component Inspection

1.CHECK FUEL INJECTOR

1. Turn ignition switch OFF.

2. Disconnect fuel injector harness connector.

3. Check resistance between fuel injector terminals as per the following.

Is the inspection result normal? YES >> INSPECTION END

NO >> Replace malfunctioning fuel injector.

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