ROTARY ENGINES

Carbureted Vehicles

NOTE: All 1979–83 RX-7s were equipped with a carburetor. 1984–85 RX-7s were equipped with either a carburetor (12A engine) or fuel injection (13B engine).

1. If possible, set up an extra cooling fan to blow additional air into the engine compartment.
2. Set the parking brake and block the wheels.
3. Switch all accessories to the off position.
4. Remove the fuel tank filler cap.
5. On 1979–83 models, disconnect and plug the hose at the idle compensator in the air cleaner. On 1984–85 vehicles with a manual transmission, disconnect the richer solenoid connector.

   NOTE: On 1981–83 models, make sure the throttle opener (if equipped with air conditioning) and dashpot do not prevent the idle lever from returning to the idle stop.

6. Connect a tachometer to the engine.
7. Start the engine and allow it to reach normal operating temperature. On vehicles equipped with an automatic transmission, shift the selector lever to the D (Drive) position.
8. Check the idle speed with the tachometer. (Read the tachometer as if testing a conventional 4-cylinder engine.) If the idle speed is not correct, adjust it by turning the throttle adjusting screw on the carburetor.

   NOTE: Read the tachometer's 4-cylinder scale, for both rotary and piston engines. If the tachometer has only a 6-cylinder scale and an 8-cylinder scale, read the 8-cylinder scale and multiply all readings by two to get the correct rpm. For example, if the specified rpm is 700, set the idle speed at 350 rpm, as indicated on the 8-cylinder scale.

9. Unplug and reconnect the hose at the idle compensator on the air cleaner, or secure the richer solenoid connector, if applicable. Install the fuel tank filler cap.

   NOTE: After adjusting idle speed, the throttle sensor on the carburetor should also be adjusted. For information on that procedure, please refer to Section 5 of this manual.

10. Disconnect the tachometer and unblock the wheels.

Fuel Injected Vehicles

1984–85 RX-7

1. Switch all electrical accessories to the off position and remove the fuel filler cap.
2. Start the engine and let it run until it reaches normal operating temperature.

   Fig. 1: Use a pair of voltmeters or test lights to check the throttle sensor setting — 1984–85 fuel injected RX-7

   Fig. 2: If necessary, turn the throttle sensor adjusting screw — 1984–85 fuel injected RX-7

   Fig. 3: Adjust idle speed by turning the AAS

3. Check/adjust the throttle sensor by performing the following:
   1. With the engine OFF, connect a pair of voltmeters to the green check connector as shown in the illustration. If voltmeters are not available, a dual set of test lights may be used instead.
   2. Turn the ignition switch ON and check to see if current flows to one of the voltmeters. When using the test light method, the light will illuminate when current flows.
   3. If there is no current, remove the rubber cap from the throttle sensor screw and turn the screw clockwise only until current flow is indicated on one of the voltmeters (or test lights). If both voltmeters show current, remove the cap and turn the screw counterclockwise so that current flows to only one voltmeter (or test light).
   4. Install the rubber cap and disconnect the voltmeters.
4. Once the throttle sensor is adjusted, disconnect the vent and vacuum solenoid connector.
5. Connect a tachometer, then start the engine.
6. Adjust the idle speed to 800 rpm by turning the Air Adjust Screw (AAS) on the throttle body. After adjusting the idle speed, reinstall the blind cap onto the AAS, if so equipped.
7. Shut off the engine, then attach the vent and vacuum solenoid connector. Disconnect and remove the tachometer, then install the fuel tank filler cap.

1986–89 RX-7

1. Switch off all electrical accessories. Start the engine and let it run until it reaches normal operating temperature, then shut off the engine.
2. Connect a jumper wire to the terminals of the initial set coupler.
3. Connect a tachometer to the service coupler at the trailing side coil with igniter. If the tachometer does not function correctly, reconnect it at the leading side coil with igniter (black coupler).

   NOTE: If using an inductive (secondary pick-up) type tachometer, connect it only at the trailing side of the spark plug wires. If connected at the leading side coil with igniter, it will not function properly.

4. Check/adjust the throttle sensor by performing the following:
   1. With the engine OFF, connect dual checker lamps 49 F018 001 or equivalent to the green check connector.
   2. Turn the ignition switch to the ON position and check that one of the lamps illuminates.
   3. If both lamps illuminate or neither one does, turn the throttle sensor adjusting screw until only one of the lamps illuminates. If both of the lamps illuminate, remove the rubber cap and turn the screw counterclockwise. If neither lamp illuminates, turn the screw clockwise. Do not use excessive pressure on the screw.
   4. Remove the checker lamps and reinstall the rubber cap.
5. On 1986–89 non-turbo models, remove the blind cap from the throttle body and adjust the idle speed by turning the Air Adjust Screw (AAS). On 1987–89 turbocharged models, remove the blind cap from the Bypass Air Control (BAC) valve and adjust the idle speed by turning the AAS.
6. When adjustment is complete, shut the engine OFF, then disconnect and remove the tachometer.

   Fig. 4: Connect a jumper wire to the terminals of the initial set coupler — 1986–89 RX-7

   Fig. 5: Connect a tachometer to the service coupler at the trailing side coil with igniter — 1986–89 RX-7

   Fig. 6: Use dual checker lamps to verify the throttle sensor setting — 1986–89 RX-7

   Fig. 7: If necessary, turn the throttle sensor adjusting screw — 1986–89 non-turbo RX-7

   Fig. 8: If necessary, turn the throttle sensor adjusting screw — 1986–89 turbocharged RX-7

   Fig. 9: Adjust the idle speed by turning the AAS on the throttle body — 1986–89 non-turbo RX-7

   Fig. 10: On turbocharged RX-7 models, the AAS is located on the BAC valve

7. Install the blind cap and disconnect the jumper wire from the initial set coupler.

   NOTE: Be sure to remove the jumper wire, otherwise engine performance will be reduced.