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

Fuel Injectors



See Figure 1

  1. Release the fuel system pressure and disconnect the negative battery cable.
  3. Disconnect the air, vacuum and water hoses from the throttle body and air funnel. Plug the water hoses to prevent leakage.
  5. Loosen the hose clamps and remove the air funnel.
  7. Disconnect the Bypass Air Control (BAC) valve connector and water hoses, then remove the valve.
  9. Detach the throttle sensor connector and the accelerator cable. Remove the throttle body and gasket. Disconnect all vacuum hoses, EGR pipe, EGR position sensor connector, water hose and ground wire.
  11. Remove the wiring harness bracket. Disconnect the air intake pipe from the dynamic chamber with the gasket. Mark the extension manifolds RIGHT and LEFT for assembly reference, as they are not interchangeable. Remove the six extension manifolds with their gaskets from the dynamic chamber.
  13. Disconnect the intake air thermo sensor connector, vacuum hoses and ground connectors. Remove the attaching nuts and lift the dynamic chamber straight up from the intake manifold studs.
  15. Detach the injector electrical connectors and the fuel hoses from the pressure regulator, then 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. Repeat this procedure for the fuel rail on the other side.
  17. 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.
  19. Installation is essentially the reverse of the removal procedure. 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.
  21. Reattach all the injector connectors securely. The injector connectors are color coded black and white. The No. 1, No. 3 and No. 5 connectors are black, and the No. 2, No. 4. and No. 6 connectors are white (see illustration).
  23. After installation, jumper the fuel pump connector, as described under the fuel pump testing procedures, and check for injector leaks. Make repairs as necessary, before operating the engine. Check for water leaks also.

Click image to see an enlarged view

Fig. Fig. 1: Injector harness connector routing-929


Injector Continuity

You can test injectors electrically either on or off the car. Unfasten the wiring and connect an ohmmeter between the two prongs of the electrical connector. The injectors used in the 929 should have a resistance of 12-16 ohms.

Injector Fuel Leak
  1. Relieve the fuel system pressure.
  3. Remove the delivery pipe and fuel injectors. Affix the injectors to the distribution pipe with some wire.

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.
  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. After one minute, a drop of leakage is acceptable.
  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.