Mazda 323/626/929/GLC/MX-6/RX-7 1978-1989

Fuel Injectors

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REMOVAL & INSTALLATION



323 Models
  1. Properly relieve the fuel system pressure, then allow the engine to cool and disconnect the negative battery cable.
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  3. Disconnect the accelerator cable from the throttle linkage.
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  5. Unclamp and disconnect the air intake tube from the throttle body.
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  7. Label, then disconnect the vacuum hoses at the throttle body.
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  9. Disconnect the PCV and evaporative control system hoses.
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  11. Detach the throttle position sensor connector.
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  13. In order to obtain the necessary clearance on vehicles through 1987, remove the attaching nuts from the underside of the air intake surge tank (upper portion of the intake manifold), then remove it and the gasket.
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  15. For 1988-89 models, unfasten the nuts from the mounting studs for the throttle body, and remove it from the dynamic chamber. Make sure to remove the gasket(s) and spacer.
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  17. Detach the injector electrical connectors and cover the high pressure fuel connections with a rag. Unfasten the banjo connector from the top of the fuel distribution pipe, and the high pressure fuel line from the bottom of the fuel pressure regulator.
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  19. Remove the two mounting bolts from the underside of the fuel distribution pipe. Gently pull the assembly away from the intake manifold so the injectors and seals slide out of their recesses in the manifold. Pull the injectors and seals out of the distribution pipe.
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  21. Installation is the reverse of the removal procedure. Be sure to coat the injector O-rings with clean engine oil prior to installation. When inserting the injectors into the distribution pipe, make sure that they are installed straight and not cocked, or fuel leakage will result. Torque the delivery pipe bolts to 14-19 ft. lbs. (19-26 Nm). Reattach all connectors securely. Jumper the fuel pump connector, as described under the fuel pump removal and installation procedure, then check for injector leaks. Make repairs as necessary, before operating the engine.
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1986-87 626
  1. Properly relieve the fuel system pressure, then allow the engine to cool and disconnect the negative battery cable.
  2.  
  3. Cover the high pressure fuel connections with a rag. Detach the outlet connection from the end of the distribution pipe, and the inlet connection from the bottom of the pressure regulator. Disconnect the vacuum line from the top of the pressure regulator.
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  5. Unfasten the injector electrical connectors and route them off to the side.
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  7. Remove the two bolts that fasten the fuel distribution pipe to the intake manifold. Gently pull the assembly away from the intake manifold so the injectors and seals slide out of their recesses in the manifold. Pull the injectors and seals out of the distribution pipe.
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  9. Installation is the reverse of removal. Use new injector seals at both ends. Reattach all connectors securely. Jumper the fuel pump connector, as described under the fuel pump removal and installation procedure, and check for injector leaks. Make repairs as necessary, before operating the engine.
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1988-89 626 and MX-6
  1. Properly relieve the fuel system pressure and disconnect the negative battery cable.
  2.  
  3. Unbolt and remove the injector wiring harness bracket.
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  5. On non-turbo models, unbolt and remove the EGR modulator valve bracket.
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  7. Remove the vacuum pipe mounting bolts and disconnect the vacuum pipe from the side of the rocker arm cover.
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  9. Loosen the hose clamp and disconnect the flexible air hose from the throttle body.
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  11. Unfasten the four bolts that attach the engine hanger bracket to the block and remove the bracket.
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  13. Unfasten the dynamic chamber mounting bolts and nuts, then raise the unit off the block and remove it from the engine. Cover the opening with a clean rag or masking tape to prevent anything from falling into the engine.
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  15. Remove the two mounting clamps that secure the fuel return pipe to the intake manifold. Detach the injector connectors. Gently pull the delivery pipe with pressure regulator and pulsation damper away from the intake manifold so the injectors and seals slide out of their recesses in the manifold. Pull the injectors, grommets and insulators out of the distribution pipe.
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  17. Installation is essentially the reverse of removal. Use new injector seals at both ends. Coat the injector seals with clean engine oil prior to installation. When inserting the injectors into the distribution pipe, make sure that they are installed straight and not cocked or fuel leakage will result. Torque the delivery pipe, dynamic chamber and engine hanger bolts to 14-19 ft. lbs. (19-26 Nm). Reattach all connectors securely. Jumper the fuel pump connector, as described under the fuel pump removal and installation procedure, and check for injector leaks. Make repairs as necessary, before operating the engine.
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TESTING



Injector Continuity

You can test injectors electrically either on or off the car. Unfasten the electrical connector and attach an ohmmeter between the two prongs of the electrical connector. The injectors used in the 323 should have a resistance of 1.5-3 ohms; those used in the 626 and MX-6 should have a resistance of 12-16 ohms.

Injector Fuel Leak
  1. Relieve the fuel pressure from the fuel system.
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  3. Remove the delivery pipe and fuel injectors. Affix the injectors to the distribution pipe with some wire. On 323, connect the delivery pipe and injector assembly between the fuel filter and the return pipe and secure with wire as previously mentioned.
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Affix the injectors firmly to the distribution pipe so no movement of the injectors is possible.

  1. Turn the ignition switch to the ON position. Use a jumper wire and connect the terminals of the fuel pump check connector. Make sure that the fuel does not leak from the injector nozzles.
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  3. After approximately five minutes, a very small (slight) amount of fuel leakage from the injectors is acceptable. If this leakage exceeds more than a few drops, replace the injector.
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  5. If the injector leaks fuel at a fast rate, replace the injector. If the injectors do not leak, remove all test equipment and install the components in the reverse order of their removal.
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