1978 Models (Except RX7)
- Turn ignition on. Unplug connector at anti-afterburn valve solenoid. See Fig 1. A "clicking" sound should be heard from solenoid when disconnected. If not, replace solenoid.
- Connect tachometer to engine. Start and run engine at idle. Disconnect air hose from deceleration control valve at air cleaner. Block air hose opening with hand. Engine speed should not change noticeably.
- On manual transmission equipped vehicles, plug hose opening with hand and disconnect coasting valve solenoid wire. Suction should now be felt at air hose opening.
- Reconnect coasting valve solenoid wire. Block hose opening with hand and disconnect anti-afterburn valve solenoid wire. Suction should be felt at air hose opening. Reconnect wire.
Courtesy of MAZDA MOTORS CORP.
- On manual transmission equipped vehicles, disconnect coasting valve-to-intake manifold air hose (at valve). Block hose and valve air outlet. Increase engine speed to 4000 RPM. Quickly release accelerator. Air should be sucked into air hose. If not, replace control valve.
- On manual transmission equipped vehicles, unplug idle switch connector. Disconnect coasting solenoid wire and connect wire to battery positive terminal. Connect voltmeter to coating valve lead from control unit. Increase engine speed to 2000 RPM.
- Slowly decrease engine speed and note RPM when current flows. Current should flow at 1050-1250 RPM and continue to flow until idle speed is reached. Slowly increase engine speed and note RPM when current stops. Speed should be within 80-220 RPM of current flow RPM.
- Reconnect idle switch. Increase engine speed to 2000 RPM. Push idle switch lever completely to idle position. Current flow should stop.