Fuel System

MULTI-POINT FUEL INJECTION (MPFI) SYSTEM

Fuel Injector

1.2L Engine

Fig. 1: Fuel injector assembly-1.2L engine

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.
3. Tag and disconnect the electrical harnesses from the fuel injectors.
4. Disconnect and tag the hoses attached to the fuel rail.
5. Remove the fuel rail mounting bolts, then remove the fuel rail assembly carefully.
6. Remove the individual injectors from the rail by pulling lightly with a slight twist.
7. Remove the fuel injector O-rings and discard.

To install:

8. Install the injectors using new gaskets and O-rings. Lubricate the O-rings with fuel before installation.
9. Carefully install the fuel rail on the engine and install the mounting bolts.
10. Connect the electrical harnesses to the fuel rail.
11. Connect the hoses to the fuel rail.
12. Connect the negative battery cable.
13. Pressurize the fuel system and verify that there are no fuel leaks.

1.8L and 2.7L Engines

Fig. 2: Exploded view of fuel system components-1.8L engine

Fig. 3: Exploded view of fuel system components-2.7L engine

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.

On some engines, it may be necessary to remove the intake plenum to gain access to the fuel lines connecting the injectors.

3. Remove the fuel lines connecting the injectors.
4. Disconnect the fuel injector electrical harnesses.
5. Remove the injectors by pulling with a slight twist. Discard the gaskets and O-rings.
6. Remove the injector holder plate, insulator, holder and seal. Discard the insulator and seal.

To install:

7. Install the injectors using new gaskets, seals, insulators and O-rings. Lubricate the O-rings with clean engine oil prior to installation.
8. Install the fuel lines connecting the injectors.
9. Connect the injector electrical harnesses.
10. Install the intake plenum if removed.
11. Connect the negative battery cable.
12. Start the engine and check for leaks.

2.2L and 2.5L Engines

Fig. 4: Fuel injector assembly-2.2L and 2.5L engines

Fig. 5: Unfasten the fuel injector wire harness from the top of the injector assembly

Fig. 6: Remove the fuel injector cover retainer screw from one side of the injector ...

Fig. 7: ... then unfasten the other retainer screw

Fig. 8: Lift the cover off ...

Fig. 9: ... and remove the seal

Fig. 10: Carefully remove the fuel injector from the cylinder head

Fig. 11: Remove the lower injector O-ring

Fig. 12: If necessary, remove a stuck O-ring with a pick tool

Fig. 13: Remove the upper O-ring from the injector. Discard all used O-rings

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.
3. Disconnect the fuel injector electrical harness.
4. Remove the fuel injection cover.
5. Remove the fuel injector from the fuel pipe assembly.
6. Remove and discard the fuel injector O-rings and insulators,

To install:

7. Install the injector with two new O-rings and a new insulator. Tighten the bolts to 24 inch lbs. (3 Nm).
8. Install the fuel injector cover.
9. Connect the fuel injector electrical harness.
10. Connect the negative battery cable.
11. Start the engine and check for leaks.

3.3L Engine

Fig. 14: Exploded view of fuel system components-3.3L engine

1. Relieve the fuel system pressure.
2. Disconnect the negative battery cable.
3. Remove the collector cover.
4. Remove the air duct between the throttle body and mass airflow sensor.
5. Remove the retainer bolts attaching the power steering hose to the collector and position the hose out of the way.
6. Disconnect the fuel injector electrical harness.
7. Remove the two screws securing the injector cover, then remove the cover.
8. Pull the injector out while rotating it.
9. Remove and discard the fuel injector O-rings.

To install:

10. Install the fuel injector using O-rings coated with clean engine oil.
11. Install the injector cover and cover bolts.
12. Connect the electrical harness to the fuel injector.
13. Install the power steering hose to the intake collector.
14. Install the air intake duct.
15. Install the intake collector cover.
16. Connect the negative battery cable.
17. Pressurize the fuel system and verify that there are no leaks.

1.2L Engine

1. Using a stethoscope, ensure that a clicking sound is heard at each injector (when idling or cranking the engine).
2. Turn the ignition switch to the OFF position, then unfasten the control unit connector.
3. Measure the voltage between fuel injector connector terminal 1 and ground. Resistance should be 9 volts or above. If not, repair the fuel injector power circuit.
4. Measure resistance between the fuel injector connector terminals. Resistance should be as follows:
   • Terminals 1 and 2: 10-18 ohms
   • Terminals 1 and 3: 10-18 ohms
   • Terminals 1 and 4: 10-18 ohms
5. If resistance is not within specification, repair the engine harness. If the engine harness is good, replace the fuel injector.
6. Connect the fuel injector connector. Turn the ignition ON.
7. Measure the resistance between ECU connector terminals and ground. Resistance should be as follows:
   • Terminal 12 and ground: 8 volts or more
   • Terminal 25 and ground: 8 volts or more
   • Terminal 11 and ground: 8 volts or more
8. If not within specification, repair the harness connector between ECU and fuel injectors.
9. Turn the ignition OFF and disconnect the ECU connector.
10. Measure resistance between the ECU connector terminal and ground. Resistance should be as follows:
    • Terminal 13 and ground: below 10 mega-ohms
    • Terminal 26 and ground: below 10 mega-ohms
11. If not within specification, repair the harness connector between the ECU and ground.

1.8L Engine

1. Using a stethoscope, ensure that a clicking sound is heard at each injector (when idling or cranking the engine).
2. Turn the ignition switch to the OFF position, then disconnect the control unit connector.
3. Using a voltmeter, measure voltage between ground and terminals 49 (W), 50 (W), 51 (WR) (WL on XT models), and 52 (WR) (WL on XT models) on the control unit connector.
4. The voltmeter should read 12 volts at all terminals.
   1. If the voltmeter reads below 10 volts in any line, the harness from the battery to the control unit through the resistor and injector is broken or shorted.
5. Disconnect each fuel injector electrical connector.
6. Using an ohmmeter, measure resistance between the terminals of each injector. The ohmmeter should read 2-3 ohms at each injector. If the ohmmeter reads infinity, the circuit is broken. If the ohmmeter reads 0 ohms, the circuit is shorted. Replace the injector.
7. Using a voltmeter, measure voltage between the terminals of each injector connector and ground. The voltmeter should read 12 volts. If voltage obtained is less than 10 volts, the harness from the battery to the injector through the resistor is disconnected or shorted.
8. Disconnect the electrical harness from the resistor.
9. Using an ohmmeter, measure the resistance between terminals (W) and (B) of the resistor. The ohmmeter should read 5.8-6.5 ohms. If the reading are not as specified, replace the resistor.
10. Using a voltmeter, measure voltage between terminal 5 (R) of the body harness connector and ground. The voltmeter should read 12 volts.

2.2L and 2.5L Engines

1. Using a stethoscope, ensure that a clicking sound is heard at each injector (when idling or cranking the engine).
2. Disconnect the fuel injector connector.
3. Measure the voltage between fuel injector connector terminal 2 and ground. Voltage should be 10 volts minimum. If not, repair the harness or connector.
4. Measure the resistance between the injector terminals. Resistance should be 10-12 ohms. If not, replace the fuel injector.
5. Fasten the fuel injector connector.
6. Measure the voltage between each fuel injector terminal of the ECU connector and ground. Resistance should be as follows:
   • Terminal 11 and ground: 10 volts minimum
   • Terminal 12 and ground: 10 volts minimum
   • Terminal 13 and ground: 10 volts minimum
   • Terminal 26 and ground: 10 volts minimum
7. If not within specification, repair the harness or connector.
8. Disconnect ECU connector.
9. Measure the resistance between ground and ECU connector terminals 24 and 25. Resistance should be 0 ohms, if not, repair the harness or connector.

2.7L Engine

1. Using a stethoscope, ensure that a clicking sound is heard at each injector (when idling or cranking the engine).
2. Disconnect the control unit connector.
3. Using a voltmeter, measure voltage between ground and terminals 49 (W), 50 (W), 51 (WR), 52 (WR), 53 (WY) and 54 (WY) on the control unit connector.
4. The voltmeter should read 12 volts at all terminals.
5. If the voltmeter reads below 10 volts in any line, the harness from the battery to the control unit through the resistor and injector is broken or shorted.
6. Disconnect each fuel injector electrical connector.
7. Using an ohmmeter, measure resistance between the terminals of each injector. The ohmmeter should read 13.8 ohms at each injector. If the ohmmeter reads infinity, the circuit is broken. If the ohmmeter reads 0 ohm, the circuit is shorted. Replace injector.
8. Using a voltmeter, measure voltage between the terminals of each injector and ground. The voltmeter should read 12 volts at each injector. If the voltage obtained is less than 10 volts at any injector, the harness from the battery to the injector is disconnected or shorted.

3.3L Engine

1. Using a stethoscope, ensure that a clicking sound is heard at each injector (when idling or cranking the engine).
2. Turn the ignition switch OFF. Disconnect the fuel injector connector.
3. Measure the voltage between fuel injector connector terminal 2 and ground. Voltage should be 10 volts minimum. If not, repair the harness or connector.
4. Measure the resistance between the injector terminals. Resistance should be 11-12 ohms. If not, replace the fuel injector.
5. Fasten the fuel injector connector.
6. Measure the voltage between each fuel injector terminal of the ECU connector and ground. Resistance should be as follows:
   • Terminal 1 and ground: 10 volts minimum
   • Terminal 11 and ground: 10 volts minimum
   • Terminal 12 and ground: 10 volts minimum
   • Terminal 13 and ground: 10 volts minimum
   • Terminal 26 and ground: 10 volts minimum
   • Terminal 12 (connector E59) and ground: 10 volts minimum
7. If not within specification, repair the harness or connector.
8. Disconnect the ECU harness.
9. Measure the resistance between ground and ECU connector terminals 24 and 25. Resistance should be 0 ohms, if not, repair the harness or connector.

END OF SECTION