Air Management System Mazda RX-7 FC

DESCRIPTION

Air management system consists of secondary air injection control system, By-Pass Air Control (BAC) and air induction system. Secondary air injection control system consists of air pump, 2 check valves, air control valve, switching solenoid valve, relief solenoid valve, split air solenoid valve and port air solenoid. Air injection system supplies air into the exhaust system to help control exhaust emissions.

The By-Pass Air Control System (BAC) controls the amount of by-pass air to maintain idling speed. System consists of by-pass air control valve, air by-pass solenoid valve, air supply valve (turbo) and air by-pass relay on non-turbo models.

The air induction system consists of throttle body, throttle diaphragm, check valve and auxiliary port valve actuator.

Scheme 4

Scheme 5

Air By-Pass Relay (Non-Turbo)

Used in controlling operation of air by-pass solenoid valve.

Air By-Pass Solenoid Valve

Directs by-pass air into primary intake manifold.

Air Control Valve

Directs air to one of 3 locations; exhaust port, main converter or relief silencer. Consists of relief valve, air switching valve and anti-afterburn valve.

Air Pump

Supplies secondary air to the air control valve.

Air Supply Valve (Turbo)

Supplies by-pass air into dynamic chamber on intake manifold during A/C and power steering operation.

Auxiliary Port Valve (Non-Turbo)

Auxiliary port valve is mounted in the intake manifold. Valve is controlled by a vacuum controlled actuator.

By-Pass Air Control Valve (BAC)

Controls amount of by-pass air to dynamic chamber. Controlled by signal from ECU.

Check Valves

Used to allow air passage in one direction only.

Port Air Solenoid Valve

Switches secondary air to exhaust port.

Relief Solenoid Valve

Controls operation of relief valve.

Split Air Solenoid Valve

Controls amount of split air.

Switching Solenoid Valve

Controls switching valve contained in the air control valve.

Throttle Body Assembly

Controls amount of intake air.

Note. For system input diagnosis, see ENGINE CONTROL SYSTEM in the COMPUTERIZED ENGINE CONTROLS section.

INSPECTION

Note. For complete vacuum schematics, see VACUUM DIAGRAMS article.

1. With engine at normal operating temperature, inspect all hose connections and belt tension.
2. Stop engine. Disconnect line from air pump to air control valve at the valve. Install Pressure Gauge Set (49 2113 010B) to the line. (Scheme 6) Connect tachometer to engine.
3. Start engine. Operate engine at idle and note pressure reading. Reading should exceed 1.7 psi (.12 kg/cm 2 ). Replace pump if not within specification.

Scheme 6

Intake Manifold Check Valve

Disconnect air pump-to-air control valve air hose at the air pump. Install tachometer and start engine. Disconnect switching solenoid valve connector. Accelerate engine to 1500 RPM. Check for exhaust leakage at air control valve inlet fitting. (Scheme 7) Replace check valve if leakage exists.

Scheme 7

Converter Air Line Check Valve

Disconnect intake manifold-to-converter check valve hose at the check valve. Install tachometer and start engine. Accelerate engine to 1500 RPM. Check for exhaust leakage from check valve opening. Replace check valve if leakage exists.

Scheme 8

Scheme 9

1. Operate engine to normal operating temperature. Stop engine and install tachometer. On turbo models equipped with Anti-Lock Brake Systems (ABS), disconnect and plug air hose and vacuum hose of air by-pass valve from the turbo. CAUTION: On turbo models with Anti-Lock Brake Systems (ABS), ensure air hose and vacuum hose of air by-pass valve are disconnected and plugged prior to removing air silencer-to-air control valve hoses.
2. On all models, disconnect air silencer-to-air control valve hose at air control valve. Place finger over air control valve outlet. Start engine and increase engine speed to 3750 RPM on turbo models or 1500-2000 RPM on non-turbo models. Note that air begins to flow at specified RPM.
3. Operate engine at idle. On turbo models, disconnect relief valve solenoid Blue connector. (Scheme 8) On non-turbo models, disconnect relief valve solenoid-to-air control valve hose. (Scheme 8)
4. Check that air flows from air control valve outlet above 1200 RPM on turbo models or at idle on non-turbo models. Reconnect vacuum hose or Blue connector.
5. Remove intake manifold-to-check valve hose. Disconnect hose at check valve on turbo models or intake manifold on non-turbo models. Place finger over opening.
6. On turbo models, disconnect hose at air control valve at air control valve. (Scheme 9) On non-turbo models, disconnect hose at switching solenoid valve. (Scheme 8)
7. With engine at idle, note that air flows from intake manifold fitting (non-turbo) or check valve (turbo). Replace air control valve if necessary. Reconnect all hoses.

Relief Solenoid Valve Signal Check (Non-Turbo)

1. Install tachometer. Warm engine to normal operating temperature. Allow engine to idle. Remove at relief solenoid valve. (Scheme 8) Increase engine speed to 1500 RPM while placing finger over end of port opening.
2. Remove throttle sensor connector. Note if air is drawn into the port opening for approximately 120 seconds, then stops. Allow engine to idle, note if air is drawn into the port opening for approximately 8 seconds.
3. Install throttle sensor connector. Increase engine speed to 3400-3600 RPM. Note that air is not drawn into the port opening.
4. Remove right seat and floor mat. Remove connector at heat hazard sensor. Install jumper wire between connector terminals to the ECU. Check that air is not drawn into the port opening at any engine speed. Remove jumper wire and install connector.
5. Turn ignition off. Disconnect coolant temperature switch connector located on the radiator. Start engine. Increase engine speed, checking that air is not drawn into port opening when engine speed exceeds 1000-1200 RPM.

Scheme 10

1. Install tachometer. Warm engine to normal operating temperature. Allow engine to idle. Connect Checker Light (49 F018 001) to Green connector. (Scheme 10)
2. Remove relief solenoid valve-to-air control valve hose at air control valve. Cover valve port with finger. Note that Green checker light activates and air flows at designated areas. See «GREEN CHECKER LIGHT OPERATION»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#air-management-system) table. NOTE: Checker light may occasionally turn off at approximately 1200 RPM. GREEN CHECKER LIGHT OPERATION Engine Condition Air Flow Light Operation Idle No On Above 3750 RPM Yes Off Deceleration No On
3. Remove right seat and floor mat. Disconnect heat hazard sensor connector. Install jumper wire to terminals of connector to the ECU. Ensure Green checker light does not activate and air flows from valve port at any engine speed. Remove jumper wire. Install connector at heat hazard sensor.
4. Turn ignition off. Remove connector from coolant temperature switch located on the radiator. Start engine. Increase engine speed, noting that Green checker light does not acitivate and air flows from valve port when engine speed exceeds 1000-1200 RPM.

Switching Solenoid Valve Signal Check (Non-Turbo)

1. Install tachometer. Warm engine to normal operating temperature and allow to idle. Disconnect hose at switching solenoid valve. (Scheme 8) Place finger over port.
2. Slowly increase engine speed, noting that air is drawn into valve port. Disconnect throttle sensor connector. Slowly increase engine speed, noting that air is not drawn into valve port when engine speed exceeds 1000-1200 RPM.

Switching Solenoid Valve Signal Check (Turbo)

1. Install tachometer. Warm engine to normal operating temperature. Allow engine to idle. Connect Checker Light (49 F018 001) to Green connector. (Scheme 10)
2. Disconnect hose at air control valve. (Scheme 9) Cover valve port with finger and note that Red checker light activates and air is drawn into valve at designated areas. See «RED CHECKER LIGHT OPERATION»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#air-management-system) table.

RED CHECKER LIGHT OPERATION

Split Air Solenoid Valve (M/T Models)

1. Connect voltmeter at BLK/WHT (turbo) or BLU/BLK (non-turbo) wire terminal and ground of solenoid valve.
2. Turn ignition on. Place transmission in 5th gear and note voltage. Voltage should be below 2.5 volts in 5th gear and approximately 12 volts in all other gears.

Split Air Solenoid Valve (A/T Non-Turbo Models)

1. Connect voltmeter at BLU/BLK wire terminal and ground of solenoid valve.
2. Place gearshift in "D" range. Remove oil pressure switch connector on side of transmission. Install jumper wire between connector and ground. (Scheme 11)
3. Turn ignition on and note voltage. Voltage should be below 2.5 volts with jumper wire installed or approximately 12 volts with jumper wire removed.

Scheme 11

Port Air Solenoid Valve (Turbo)

Install jumper wire between BLK/RED wire terminal and ground of solenoid valve. Turn ignition on and listen for operating sound of solenoid valve. Replace valve if no operating sound is heard.

Port Air Solenoid Valve (Non-Turbo)

1. Install voltmeter between BLK/RED and ground of solenoid valve. Start engine. Allow to idle and note voltage reading. Voltage should be below 2.5 volts.
2. Disconnect throttle sensor connector and note voltage. Voltage should be approximately 12 volts.

Note. Solenoid valve voltage will be constantly below 2.5 volts once vehicle has operated over 20,000 miles.

Scheme 12

BY-PASS AIR CONTROL SYSTEM (BAC)

By-Pass Air Control Valve (BAC) Check

1. Install jumper wire at initial set coupler. (Scheme 13) Install tachometer. Operate engine to normal operating temperature. Allow engine to idle.
2. Disconnect BAC valve connector. (Scheme 14) Note engine RPM. Engine speed should decrease with connector removed. Reinstall connector.

Scheme 13

Scheme 14

Air By-Pass Solenoid Valve Signal

1. Disconnect coolant thermosensor connector. Install 2000 ohm resistor to terminals of thermosensor connector. Install voltmeter at BRN/YEL wire terminal of connector and ground.
2. Start engine and note voltage. Voltage should read zero (0) volts for 17 seconds after engine is started. After 17 seconds, voltage should increase to 12 volts.

1. Warm engine to normal operating temperature. Allow engine to idle. Remove hose connecting intercooler to dynamic chamber at the intercooler.
2. Place finger over port opening. Check that air is drawn into intercooler port. Turn steering wheel either direction. Check that air is drawn into port.

RELIEF SOLENOID VALVE (NON-TURBO)

1. Disconnect vacuum hoses from relief solenoid valve. Blow through port "B". (Scheme 15) Air should flow from air filter. Remove connector from solenoid valve.
2. Apply battery voltage and ground to proper terminals. (Scheme 15) Blow through port "B". Air should flow from port "A".

Scheme 15

RELIEF SOLENOID VALVE (TURBO)

1. Disconnect vacuum hoses from relief solenoid valve. Blow through port "A". (Scheme 15) Air should flow from port "B". Remove connector from solenoid valve.
2. Apply battery voltage and ground to proper terminals. (Scheme 15) Blow through port "A". Air should flow from air filter.

1. Disconnect vacuum hoses from switching solenoid valve. Blow through port "A". (Scheme 16) Air should flow from port "B". Remove connector from solenoid valve.
2. Apply battery voltage and ground to proper terminals. (Scheme 16) Blow through port "A". Air should flow from air filter.

Scheme 16

BAC VALVE

1. Disconnect valve connector. Using ohmmeter, check resistance between valve terminals. Resistance should be 10.7-12.3 ohms. Apply battery voltage and ground to valve terminals.
2. Listen for operating sound from valve. Replace valve if resistance is not within specification or no operating sound exists.

Disconnect valve connector. Using ohmmeter, check resistance between valve terminals. Replace valve if resistance is not within specification. See AIR BY-PASS SOLENOID VALVE RESISTANCE SPECIFICATIONS table.

1. Connect positive battery lead to relay terminal "A" and ground to terminal "B". (Scheme 17) Using ohmmeter, check continuity between terminals "C" and "D".
2. Continuity should exist with battery connected and no continuity with battery disconnected. Replace relay if defective.

Scheme 17

AIR SUPPLY VALVE

Remove valve connector. Using ohmmeter, check resistance between terminals of air supply valve. Resistance should be between 16.2-19.8 ohms. Replace valve if not within specification.

Scheme 18

1. No. 1 secondary throttle valve starts to open when primary valve opens with proper amount of degrees. (Scheme 18) Secondary throttle valve should be completely open when the primary valve fully opens.
2. Check clearance between primary throttle valve and throttle bore wall when No. 1 secondary valve starts to open. Clearance should be within specification. See PRIMARY THROTTLE VALVE CLEARANCE table. If clearance is not within specification, bend tab until the proper clearance is obtained. (Scheme 19)

PRIMARY THROTTLE VALVE CLEARANCE

Scheme 19

Fast Idle Operation

1. Engine and throttle body must be at temperature of 77°F (25°C) prior to checking. Check that matching mark on fast idle cam is aligned with center of cam roller. (Scheme 20)
2. If alignment of marks is required, rotate cam adjusting screw until alignment is obtained. Once correct mark alignment is obtained, check clearance between primary throttle valve and throttle bore wall. Clearance should be.016-.020" (.41-.51 mm). Adjust clearance with fast idle adjusting screw. (Scheme 19)

Scheme 20

Accelerator Linkage

1. Check cable free play at throttle body. Free play should be .04-.12" (1.0-3.0 mm). If not within specification, adjust with nut located on throttle cable housing end at throttle chamber.
2. Check that throttle valves are fully open with accelerator pedal fully depressed. Adjust stopper bolt located on top of throttle pedal. Check that the accelerator linkage returns fully and does not bind.

Throttle Diaphragm

1. On M/T models, disconnect hose at throttle diaphragm. Using vacuum pump, apply at least 7.8 in. Hg to throttle diaphragm. (Scheme 21)
2. Ensure that No. 2 secondary throttle valve is fully open. On A/T models, disconnect hose from double throttle diaphragm. Using vacuum pump, apply 18.1 in. Hg to No. 2 secondary double throttle diaphragm. (Scheme 21)
3. With vacuum applied, check clearance between No. 2 secondary throttle valve and throttle bore wall when primary throttle valve is closed. Clearance should be.09-.13" (2.3-3.3 mm).

Scheme 21

Check Valve (A/T & Turbo)

Remove check valve. Blow through side "A". Air should flow from side "B". (Scheme 22) Blow through side "B". Air should not flow from side "A".

Scheme 22

Delay Valve

1. On A/T models, note installation location of delay valves. (Scheme 23) On all models, disconnect vacuum delay valve. Connect approximately 3.28 ft. of vacuum tube and delay valve to vacuum pump. Ensure valve is installed with the arrow away from the vacuum tester. (Scheme 23)
2. Block remaining side of valve with your finger. Using vacuum pump, apply at least 19.7 in. Hg to valve. Remove your finger. Note time required for vacuum reading to fall from 15.7 in. Hg to 3.9 in. Hg on each valve. Delay valve vacuum decrease time must be within specification. See «DELAY VALVE VACUUM SPECIFICATIONS»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#air-management-system) table.

Note. On A/T models, delay valve identification or installation location must be used to determine proper vacuum delay time. (Scheme 23)

Scheme 23

Coolant Thermovalve

1. Remove coolant thermovalve from throttle body. Place coolant thermovalve in container of water.
2. Heat water gradually and note temperature which air will pass through proper port location of valve. Temperature of air passage must be within specification. See «COOLANT THERMOVALVE SPECIFICATIONS»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#air-management-system) table.

Auxiliary Port Valve Actuator (Non-Turbo)

1. Auxiliary port valve in intake manifold is operated by a vacuum controlled actuator. Remove hose from actuator. Install pressure gauge on line fitting.
2. Apply low compressed air to the actuator and check operation. Actuator should start to move at approximately 1.2 psi (.08 kg/cm 2 ) and be fully opened with 2.1 psi (.15 kg/cm 2 ) applied. Replace actuator if not within specification.

AIR BY-PASS SOLENOID VALVE RESISTANCE

AIR BY-PASS SOLENOID VALVE RESISTANCE SPECIFICATIONS

DELAY VALVE VACUUM

DELAY VALVE VACUUM SPECIFICATIONS

COOLANT THERMOVALVE SPECIFICATIONS

See also:
• GREEN CHECKER LIGHT OPERATION