Genuine Mazda RX-7 Fuel Injector

Mazda RX-7 Fuel Injector Parts and Q&A

• Injector
  N37013250
  Q:

  How to test and replace the fuel pump, fuel pressure regulator, fuel injector, pulsation damper, and atmospheric pressure sensor, and How to adjust the idle speed on Mazda RX-7?

  A:

  To test the fuel pump, disconnect the negative battery cable, and wrap a cloth around the main fuel hose at its connection to the metal pipe. Release the clamp on the hose, pull off the hose, and attach a fuel pressure gauge on the end. Reattach the negative battery cable. Use a jumper wire to connect the fuel pump short circuit connector terminals. Turn the ignition switch on. The pump must run and the fuel pressure between 49.8 to 71.1 psi. If not, the pump requires replacement. To check the regulator, repeat the earlier steps to disconnect the negative battery cable and remove the hose. Attach a fuel pressure gauge using the T fitting. Reconnect the battery and crank the engine after that, remove the vacuum hose from the pressure regulator control valve, the fuel pressure at idle should be about 36.97 psi, after reconnecting the vacuum hose it should drop to 28.44 psi, replace the regulator if not. To take out and fit the pressure regulator, cover the starter motor, remove the air cleaner to throttle chamber duct and disconnect the dynamic chamber throttle chamber and intake manifold. Detach the vacuum and return hoses, undo the regulator from the delivery pipe, then reassemble in reverse order and check for leaking when the fuel pump runs. An injector may be bad if its sound doesn't register. To check, place a stethoscope or screwdriver against the injector while the engine is idling. No sound means check the wires and continuity. Also, check the main fusible link. Finally, make sure the main relay clicks when power is applied. The injectors should be checked for resistance after removal. The value should be anywhere between 1.5 and 3 ohms. It is recommended to get a leakage and volume check done at a dealer service department. The air cleaner duct is removed, hoses and wire harness connectors are disconnected. The delivery pipe is unbolted, and the injectors are lifted out as a set. New insulators, grommets and O-rings are used on installation. Put your finger over the pulsation damper while the engine is idling to check if there is any pulsation. To measure the atmospheric pressure sensor, connect a voltmeter across D and ground the other terminal. It should be 4 ± 0.5 volts at sea level and 3 ± 0.5 volts at a higher altitude. Before adjusting the idling speed, make sure that all accessories are off; the fuel tank cap is removed and a tachometer is connected. The engine must be switched on until its normal operating temperature and carry out the throttle sensor check-up and adjustment. Unplug the valve and vacuum solenoid valve connector. Adjust the air screw until the idle speed is 800 rpm and replace the blind cap. Unless the variable resistor is replaced, idle mixture adjustments are normally unnecessary, and it's a good idea to have a dealer service department perform the adjustment in order that emission compliance is maintained.