Toyota Celica/Supra 1971-1985 Repair Guide

Fuel Injectors

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There is one fuel injector for each cylinder. They spray fuel into the intake port, in front of the intake valve. When the injector is energized, the coil pulls the plunger up, opening the needle valve and allowing the fuel to pass through the injector. Opening of the injectors is controlled by the EFI computer. The injectors operate at low pressure and are open for only a fraction of a second at a time.

REMOVAL & INSTALLATION



Celica

See Figures 1, 2, 3, 4 and 5



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Fig. Fig. 1: Remove the intake manifold with the throttle body attached



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Fig. Fig. 2: Disconnect the injector harness



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Fig. Fig. 3: Remove the pulsation damper, then disconnect the fuel hose from the delivery pipe



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Fig. Fig. 4: Carefully remove the outer and ...



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Fig. Fig. 5: ... inner O-rings from the injector

  1. Relieve the fuel pressure. Disconnect the negative battery cable.
  2.  
  3. Disconnect the ground strap from the rear side of the engine.
  4.  
  5. Disconnect the accelerator cable.
  6.  
  7. If equipped with an automatic transmission, disconnect the throttle cable from the bracket and the clamp.
  8.  
  9. Disconnect the No. 1 and No. 2 PCV hoses.
  10.  
  11. Disconnect the No. 2 PCV hose and the Vacuum Control Valve (VCV), if equipped.
  12.  
  13. Disconnect the following items:
    1. Brake power booster hose.
    2.  
    3. Air control valve hoses.
    4.  
    5. Vacuum Switching Valve (VSV).
    6.  
    7. Evaporative emission control hose.
    8.  
    9. EGR vacuum hose and modulator.
    10.  
    11. Pressure regulator hose from the air intake chamber.
    12.  
    13. No. 1 and No. 2 air valve hose from the throttle body.
    14.  
    15. No. 2 and No. 3 water bypass hoses from the throttle body.
    16.  
    17. Cold start injector wire.
    18.  
    19. Throttle position wire.
    20.  

  14.  
  15. Remove the following items:
    1. Cold start injector-to-chamber bolt.
    2.  
    3. No. 1 EGR pipe-to-chamber bolts.
    4.  
    5. Manifold stay-to-chamber bolts.
    6.  
    7. Fuel hose clamp, 4 bolts, 2 nuts and the bond strap.
    8.  
    9. Air intake chamber with throttle body and gaskets.
    10.  

  16.  
  17. Disconnect the fuel return hose.
  18.  
  19. Disconnect the following wires:
    1. Auxiliary air valve wire.
    2.  
    3. Knock sensor wire.
    4.  
    5. Oil pressure sender gauge/switch.
    6.  
    7. Starter wire (terminal 50).
    8.  
    9. Transmission wires.
    10.  
    11. Air conditioning compressor wires.
    12.  
    13. Injector wires.
    14.  
    15. Water temperature sender gauge wire.
    16.  
    17. Overdrive temperature switch wire (air conditioning).
    18.  
    19. Oxygen sensor and igniter wire.
    20.  
    21. Vacuum Switching Valve (VSV) wire (air conditioning).
    22.  
    23. Cold start injector time switch wire.
    24.  
    25. Water temperature sensor wire.
    26.  

  20.  
  21. Remove the pulsation damper and gaskets, then disconnect the fuel hose from the delivery pipe.
  22.  
  23. Remove the injectors from the engine. Take care in handling the injectors.
  24.  

To install:
  1. Lubricate the O-rings with clean gasoline. Install the injectors into the delivery pipe using new O-rings.
  2.  
  3. Install the four insulators into the injector holes of the intake manifold. Install the injectors and delivery pipe assembly to the manifold, and check that each injector rotates smoothly.
  4.  
  5. Tighten the delivery pipe hold-down bolts to 14 ft. lbs. (20 Nm).
  6.  
  7. Reconnect the fuel hose to the delivery pipe. Install the pulsation damper with new gaskets.
  8.  
  9. Install the air intake chamber and throttle body with a new gasket.
  10.  
  11. Reconnect all vacuum hoses, wiring and cables.
  12.  
  13. Connect the ground strap at the rear side of the engine.
  14.  
  15. Connect the negative battery cable. Start the engine and check for leaks.
  16.  

Supra
  1. Disconnect the negative battery cable and drain the cooling system.
  2.  
  3. Relieve the fuel system pressure.
  4.  
  5. Drain the engine cooling system.
  6.  
  7. Remove the air intake connector.
  8.  
  9. Remove the No. 1 coolant bypass hose from the idle speed control valve body.
  10.  
  11. Remove the No. 2 coolant bypass hose from the throttle body.
  12.  
  13. Remove the air valve hose from the throttle body.
  14.  
  15. Remove the PCV hose from the throttle body.
  16.  
  17. Remove the brake vacuum hose from the air intake chamber.
  18.  
  19. Remove the actuator vacuum hose from the air intake chamber.
  20.  
  21. Disconnect the accelerator linkage and cable from the throttle body.
  22.  
  23. Label and disconnect the emission control hoses from the throttle body and air intake chamber.
  24.  
  25. Disconnect the following wires:
    1. Cold start injector wire.
    2.  
    3. Throttle position sensor wire.
    4.  
    5. Two ISC valve connectors.
    6.  
    7. VSV wire connector.
    8.  

  26.  
  27. Remove the air intake chamber bracket.
  28.  
  29. Remove the vacuum pipe sub-assembly.
  30.  
  31. Loosen the EGR pipe connecting nut.
  32.  


CAUTION
Fuel injection systems remain under pressure after the engine has been turned OFF. Properly relieve fuel pressure before disconnecting any fuel lines. Failure to do so may result in fire or personal injury.

  1. Disconnect the cold start fuel hose from the delivery pipe.
  2.  
  3. Remove the air intake chamber by removing the bolts.
  4.  
  5. Remove the distributor from the engine.
  6.  
  7. Remove the No. 1 fuel pipe.
  8.  
  9. Disconnect and remove the wiring harness from the injector pipe.
  10.  
  11. Remove the delivery pipe with the injectors by removing the four bolts.
  12.  
  13. Remove the injectors from the injector pipe.
  14.  
  15. Remove the six insulators from the intake manifold.
  16.  

To install:
  1. Install the six insulators to the intake manifold.
  2.  
  3. Apply a thin coat of gasoline to the O-rings and install the injectors to the injector pipe.
  4.  
  5. Install the injectors together with the delivery pipe to the intake manifold.
  6.  

Make sure that the injectors rotate smoothly.

  1. Install the four bolts to the injector pipe and torque the bolts to 10 ft. lbs. (14 Nm).
  2.  
  3. Install and connect the wiring harness to the injector pipe.
  4.  
  5. Install the No. 1 fuel pipe.
  6.  
  7. Install the distributor to the engine.
  8.  
  9. Install the air intake chamber to the engine.
  10.  
  11. Connect the cold start fuel hose to the delivery pipe.
  12.  
  13. Tighten the EGR pipe connecting nut.
  14.  
  15. Install the vacuum pipe sub-assembly.
  16.  
  17. Install the air intake chamber bracket.
  18.  
  19. Connect the following wires:
    1. VSV wire connector.
    2.  
    3. Two ISC valve connectors.
    4.  
    5. Throttle position sensor wire.
    6.  
    7. Cold start injector wire.
    8.  

  20.  
  21. Connect the accelerator linkage and cable to the throttle body.
  22.  
  23. Connect the emission control hoses to the throttle body and air intake chamber.
  24.  
  25. Connect the actuator vacuum hose to the air intake chamber.
  26.  
  27. Connect the brake booster vacuum hose to the air intake chamber.
  28.  
  29. Connect the PCV hose to the throttle body.
  30.  
  31. Connect the air valve hose to the ISC valve on the throttle body.
  32.  
  33. Connect the No. 1 coolant bypass hose to the ISC valve body.
  34.  
  35. Connect the No. 2 coolant bypass hose to the throttle body.
  36.  
  37. Install the air intake connector.
  38.  
  39. Fill the engine cooling system.
  40.  
  41. Connect the negative battery cable to the battery.
  42.  

INSPECTION



We recommend that any checking or testing of the injectors, other than that included below, be left to an authorized service facility.

Injector operation can be checked with the injectors installed in the engine. A sound scope is needed here (a stethescope-like device you can usually rent from tool rental shops; they are also available new from most auto tool and parts jobbers).

With the engine running or cranking, check each injector for normal operating noise (a buzzing or humming), which changes in proportion to engine rpm. If a sound scope is not available to you, check injector operation by touching each injector with your finger. It should be buzzing. If no sound or an unusual sound is heard, check the wiring connector, or have the injector checked professionally.

Measure injector resistance by unplugging the wiring connector from the injector, and connecting an ohmmeter. Check the continuity at both terminals; resistance should be 1.5-3.0 ohms.

 
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