Cec System Mazda RX-7 FC

DESCRIPTION

The Mazda RX7 computerized engine control system monitors various engine and vehicle functions to control engine operation and lower emissions while maintaining fuel economy and driveability.

The Electronic Control Unit (ECU), through various input sensors, monitors engine operation through the use of output devices such as fuel, air injection, ignition, EGR and turbo control systems. Knock control system is used on turbo models. Turbo operation is controlled by the turbo solenoid valve which receives controlling signals from the ECU.

A/C Switch

Switch detects A/C operation and sends signal to ECU.

Airflow Meter

Airflow meter monitors amount of intake air and sends signal to ECU.

Atmospheric Pressure Sensor

Sensor monitors atmospheric pressure and sends signal to ECU.

Battery Power Circuit

Battery power circuit provides electric current to ECU. The ECU uses this circuit to monitor battery voltage.

Boost Sensor (Non-Turbo)

Sensor monitors intake manifold vacuum and sends signal to ECU.

Clutch Switch

Clutch switch detects clutch operation and sends signal to ECU. Clutch switch is closed when pedal is depressed.

Coolant Temperature Switch

Switch monitors radiator coolant temperature and sends signal to ECU.

Coolant Thermosensor

Sensor monitors coolant temperature and sends signal to ECU.

Crank Angle Sensor

Sensor detects eccentric shaft and front rotor position and sends signal to ECU.

Heat Hazard Sensor

Sensor detects floor temperature and sends signal to ECU.

Inhibitor Switch (A/T)

Switch detects position of selector lever and sends signal to ECU.

Initial Set Coupler

Set coupler is used to deliver an initial set signal to ECU for idle mixture adjustment procedures.

Intake Air Temperature Sensor

Sensor monitors intake manifold air temperature and sends signal to ECU.

Knock Sensor (Turbo)

Sensor monitors engine knock conditions and sends signal to engine knock control unit.

Mileage Switch

Switch determines vehicle mileage and sends signal to ECU.

Neutral Switch

Switch detects gearshift Neutral position and sends signal to ECU.

Overdrive Switch (A/T)

Switch detects overdrive operation and sends signal to ECU.

Oxygen Sensor

Oxygen sensor (O2) monitors oxygen content of exhaust gases and sends signal to ECU.

Power Steering Switch

The Power Steering (P/S) switch determines when pressure is required to turn the wheels and sends a signal to ECU. On turbo models, a power steering relay is used along with the power steering switch.

Pressure Sensor (Turbo)

Sensor monitors intake manifold vacuum and sends signal to ECU.

Throttle Sensor

Sensor monitors throttle opening angle and sends signal to ECU.

Variable Resistor

Variable resistor adjusts air/fuel ratio and sends signal to ECU.

5th Gear Switch (M/T)

Switch detects engagement of 5th gear and sends signal to ECU.

Scheme 32

Scheme 33

DRIVEABILITY

Hard Or No Start (Cranks Okay)

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system operation.
3. Primary injector operation (non-turbo).
4. Main fuel line pulsations to indicate operation (turbo).
5. Coolant thermosensor.
6. Fuel pump switch.
7. Airflow meter operation.
8. Check fuel pressure.
9. Fuel leakage at injectors.
10. ECU operation.
11. Engine compression.

Rough Idle

Check the following components or conditions

1. Stored trouble codes.
2. Throttle sensor operation.
3. Ignition system and timing.
4. Idle speed.
5. Air intake system for leaks.
6. Fuel pump control system (turbo).
7. By-pass Air Control System (BAC) operation.
8. Air Control Valve (ACV) operation.
9. Coolant thermosensor.
10. Atmospheric pressure sensor.
11. Airflow meter.
12. Check idle mixture and fuel pressure.
13. Fast idle RPM.
14. EGR valve operation.
15. Intake air temp. sensor on intake pipe or chamber.
16. ECU operation.
17. Engine compression.

High Idle Speed At Normal Operating Temperature

Check the following components or conditions

1. Stored trouble codes.
2. Throttle valves operate smoothly.
3. Fast idle cam releases from roller.
4. Air intake system for leaks.
5. Throttle sensor and idle speed.
6. Air by-pass solenoid operation.
7. Ignition timing.
8. Anti-afterburn valve operation.
9. By-pass Air Control System (BAC) operation.
10. Dashpot operation.
11. Airflow meter operation.
12. Intake air temp. sensor in airflow meter.
13. ECU operation.

Engine Does Not Run Smooth At Normal Operating Temperature

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Inspect air intake system for leaks.
4. Idle speed and throttle sensor.
5. Primary injector operation (non-turbo).
6. Main fuel line pulsations to indicate operation (turbo).
7. By-pass Air Control System (BAC).
8. Air control valve operation.
9. Check idle mixture.
10. Purge control valve.
11. Coolant thermosensor.
12. EGR valve operation.
13. Airflow meter operation.
14. Intake air temp. sensor in airflow meter.
15. Fuel pressure and fuel leaks.
16. ECU operation.
17. Engine compression.

Engine Does Not Run Smooth At Cold Condition

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Inspect air intake system for leaks.
4. Idle speed and throttle sensor.
5. Check fast idle system.
6. Primary injector operation (non-turbo).
7. Main fuel line pulsations to indicate operation (turbo).
8. Check double throttle system (turbo).
9. By-pass Air Control System (BAC).
10. Air control valve operation.
11. Fuel pump control system (turbo).
12. Check variable resistor.
13. Purge control valve.
14. Coolant thermosensor.
15. EGR valve operation.
16. Airflow meter operation.
17. Intake air temp. sensor in airflow meter.
18. Fuel pressure and fuel leaks.
19. ECU operation.
20. Engine compression.
21. Check injection volume.

Engine Does Not Run Smooth At Hot Condition

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Inspect air intake system for leaks.
4. Idle speed and throttle sensor.
5. Pressure regulator control solenoid operation.
6. Primary injector operation (non-turbo).
7. Main fuel line pulsations to indicate operation (turbo).
8. By-pass Air Control System (BAC).
9. Air control valve operation.
10. Intake air temp. sensor on intake pipe or chamber.
11. Fuel pump control system (turbo).
12. Check idle mixture.
13. Purge control valve.
14. Coolant thermosensor.
15. Airflow meter operation.
16. Fuel pressure and fuel leaks.
17. ECU operation.
18. Engine compression.
19. Check injection volume.

Lack Of Power

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Initial set coupler jumper wire removed (non-turbo).
4. Inspect air intake system for leaks.
5. Air control valve operation.
6. Air filter condition.
7. Airflow meter operation.
8. Intake air temp. sensor in airflow meter.
9. Check auxiliary port valve (non-turbo).
10. Intake air temperature sensor.
11. Injector operating sound (non-turbo).
12. Check double throttle system operation.
13. Check pressure or boost sensor.
14. Main fuel line pulsations to indicate operation (turbo).
15. Throttle sensor operation.
16. Coolant thermosensor.
17. Fuel pressure and fuel leaks.
18. ECU operation.
19. Check feedback system.
20. Engine compression.
21. Check injection volume.
22. Check knock control (turbo).
23. Check turbo and wastegate valve.
24. Check turbo control system.
25. Check accelerator cable.

Afterburn

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Air intake for leaks.
4. Check idle speed.
5. Air control valve operation.
6. Check throttle sensor.
7. Dashpot operation.
8. Anti-afterburn valve operation.
9. By-pass Air Control System (BAC).
10. Injector operating sound.
11. Coolant thermosensor.
12. Intake air temp. sensor in airflow meter.
13. Airflow meter operation.
14. Check injector leakage.
15. ECU operation.
16. Engine compression.
17. Check fuel pump control system (turbo).
18. Check idle mixture.
19. EGR valve operation.

Runs Rough On Deceleration

Check the following components or conditions

1. Stored trouble codes.
2. Ignition system and timing.
3. Air intake for leaks.
4. Check idle speed.
5. Check throttle sensor.
6. Dashpot operation.
7. Air control valve operation.
8. By-pass Air Control System (BAC).
9. Injector operating sound.
10. Coolant thermosensor.
11. Intake air temp. sensor in airflow meter.
12. EGR valve operation.
13. Clutch and neutral switch.
14. ECU operation.
15. Engine compression.
16. Fuel leakage at injectors.

SELF-DIAGNOSIS

Obtain trouble codes. See TROUBLE CODES under TESTING in this article.

Scheme 34

1. Check all connections and repair as necessary. Check crank angle sensor resistance. See CRANK ANGLE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article. If resistance is okay, check for continuity between proper terminals of crank angle sensor and ECU. See ECU & SENSOR TERMINAL USAGE table. Determine terminal identification. (Scheme 34) ECU & SENSOR TERMINAL USAGE Sensor Terminal ECU Terminal G1 1N G2 1P NE1 1T NE2 1Q
2. If continuity did not exist at proper terminals, check wiring circuit. If continuity exists, ECU is defective.

Trouble Code No. 02

1. Check all connections and repair as necessary. Check airflow meter resistance. See AIRFLOW METER under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
2. If resistance is okay, check for voltage at BRN/WHT wire of airflow connector. Voltage should be 4.5-5.5 volts. If voltage is not within specification, check for faulty wiring circuit or defective ECU.
3. If voltage is correct, check for continuity between proper terminals of airflow meter and ECU. See «ECU & AIRFLOW METER TERMINAL USAGE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. Determine terminal identification. (Scheme 34)and (Scheme 35). If continuity does not exist, check wiring circuit. If continuity exists, ECU is defective.

ECU & AIRFLOW METER TERMINAL USAGE

Scheme 35

Trouble Code No. 03

1. Check all connections and repair as necessary. Check coolant thermosensor resistance. See COOLANT THERMOSENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
2. If resistance is okay, check for continuity between coolant thermosensor and ECU. Check continuity between BLK or BLK/BRN wire of coolant thermosensor and terminal "2C" of ECU and Green wire of coolant thermosensor and terminal "2I" of ECU. Determine proper ECU terminal identification. (Scheme 34)
3. If no continuity exists, check for open wiring circuit. If continuity exists, check for shorted circuit or defective ECU.

Trouble Code No. 04

1. Check all connections and repair as necessary. Check air intake temperature sensor resistance. See AIR INTAKE TEMPERATURE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
2. If resistance is okay, check for continuity between airflow meter terminal "THAa" and ECU terminal "2J". Determine terminal identification. (Scheme 34)and (Scheme 35).
3. If no continuity exists, check for open wiring circuit. If continuity exists, check for shorted circuit or defective ECU.

Trouble Code No. 05

1. Check all connections and repair as necessary. Check for continuity between oxygen sensor terminal and ECU terminal "2D". (Scheme 34) If no continuity exists, check for open or shorted circuit.
2. If continuity exists, check feedback system operation. See «FEEDBACK SYSTEM»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) under TESTING in this article. DO NOT perform step 3) under FEEDBACK SYSTEM. Repair as necessary.

Trouble Code No. 06

1. Check all connections and repair as necessary. Ensure throttle sensor is properly adjusted. See «THROTTLE SENSOR»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) under ADJUSTMENTS in this article.
2. If correctly adjusted, check throttle sensor resistance. See THROTTLE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
3. If resistance is correct, check voltage at BRN/WHT wire of throttle sensor connector. Voltage should be 4.5-5.5 volts. If voltage is not within specification, check for open or shorted circuit or defective ECU.
4. If voltage is correct, check for continuity between GRN/RED wire at throttle sensor and ECU terminal "2G" and Black wire at throttle sensor and ECU terminal "2C". If no continuity exists, check for open wiring circuit. If continuity exists, ECU is defective.

Trouble Code No. 07

1. Check all connections and repair as necessary. Check for battery voltage at BLK/WHT wire of boost sensor (non-turbo) or pressure sensor (turbo). If no voltage exists, check for open circuit from main relay to sensor.
2. If voltage exists, check for voltage at BRN/WHT wire of boost sensor (non-turbo) or pressure sensor (turbo). Voltage should be 4.5-5.5 volts. If voltage is not within specification, check for open or short circuit or defective ECU.
3. If voltage is correct, check boost or pressure sensor operation. See BOOST OR PRESSURE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article. If sensor operates properly, check for continuity between BRN/RED wire at sensor and ECU terminal "2B" and Black or BLK/BRN wire at sensor and ECU terminal "2C". Determine terminal identification. (Scheme 34)
4. If no continuity exists, check for open or shorted circuit. If continuity exists, ECU is defective.

Trouble Code No. 09

1. Check all connections and repair as necessary. Check for battery voltage at BLK/WHT wire of atmospheric pressure sensor. If no voltage exists, check for open circuit from main relay to sensor.
2. If voltage exists, check for voltage at BRN/WHT wire of atmospheric pressure sensor. Voltage should be 4.5-5.5 volts. If voltage is not within specification, check for open or shorted wiring circuit or defective ECU.
3. If voltage is within specification, check atmospheric pressure sensor operation. See ATMOSPHERIC PRESSURE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
4. If sensor operates properly, check for continuity between GRN/YEL wire at sensor and ECU terminal "2H" and BLK wire at sensor and ECU terminal "2C". Determine terminal identification. (Scheme 34) If no continuity exists, check for open or shorted wiring circuit. If continuity exists, ECU is defective.

Trouble Code No. 12

1. Check all connections and repair as necessary. Check for battery voltage at BLK/WHT wire of connector of coil with igniter (trailing side). If no voltage exists, check for open circuit from main relay to connector.
2. If voltage exists, check coil with igniter operation. See appropriate DISTRIBUTOR & IGNITION SYSTEMS article for test procedures. If coil operates properly, check for voltage at terminal "1M" of ECU with engine at idle. If voltage exists, ECU is defective.
3. If no voltage exists with engine at idle, check for voltage at BLU/RED wire of coil with igniter. If no voltage exists, coil with igniter is defective. If voltage exists, ECU is defective.

Trouble Code No. 15

1. Check all connections and repair as necessary. Check intake air temperature sensor resistance. See INTAKE AIR TEMPERATURE SENSOR under «COMPONENT TESTING»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) in this article.
2. If resistance is correct, check continuity between ECU terminal "2L" and GRN wire of intake air temperature sensor connector and ECU terminal "2C" and BLK or BRN/BLK wire of connector.
3. Check for open or shorted circuits if continuity did not exist. If continuity did exist, check for short in wiring harness circuit or defective ECU.

Scheme 36

1. Self-Diagnosis Checker (49 H018 9A1) must be used to obtain trouble codes. Warm engine to normal operating temperature. Connect self-diagnosis checker to connector. (Scheme 36)
2. Place select switch in the "B" position. Check trouble code number indicated. Compare trouble code to that listed. See «TROUBLE CODE USAGE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. «SELF-DIAGNOSIS»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system__self-diagnosis) under TROUBLE SHOOTING in this article for trouble shooting procedure. NOTE: Self-diagnosis checker buzzer will activate for approximately 3 seconds after the ignition is turned on. TROUBLE CODE USAGE Code Probable Cause 01 Crank Angle Sensor 02 Airflow Meter 03 Coolant Thermosensor 04 Intake Air Temp. Switch (Located In Airflow Meter) 05 Oxygen Sensor 06 Throttle Sensor 07 Boost or Pressure Sensor 09 Atmospheric Pressure Sensor 12 Coil W/Ignitor (Trailing Side) 15 Intake Air Temp. Switch (Located in intake pipe or dynamic chamber)
3. Monitor light on self-diagnosis checker will test O2 sensor signal. Note light operation. Determine if air/fuel ratio is correct. See «MONITOR LIGHT INDICATIONS»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. Check feedback system if incorrect air/fuel ratio is indicated.

MONITOR LIGHT INDICATIONS

Scheme 37

1. Connect self-diagnosis checker to connector. (Scheme 36) Place select switch in the "B" position. Disconnect neutral switch connector. Operate engine at idle to normal operating temperature. Shut off engine. On turbo models, remove intercooler. (Scheme 33)
2. On all models, disconnect throttle sensor connector. (Scheme 37) On turbo models, reinstall intercooler. On all models, start engine and allow to idle. Self-diagnosis checker should read trouble code 06 with monitor light on.
3. Increase engine speed to 1500-2000 RPM and note that monitor light starts to flash within 10 seconds after increasing engine speed. Trouble code 06 should be indicated with monitor light flashing more than 8 times per 10 seconds.
4. Maintain engine speed at 1750 RPM and disconnect oxygen sensor connector. (Scheme 37) Monitor light should be off and trouble code 05 should exist. Replace ECU if any deviation from normal readings exists.

ELECTRONIC CONTROL UNIT (ECU)

1. Operate engine to normal operating temperature. Connect Engine Signal Monitor (49 9200 162) and Adapter (49 9200 163) to ECU and wiring harness. Place selector switch and monitor switch on terminal voltage to be tested.
2. Turn ignition on. Note voltage of designated terminals. (Scheme 38)through (Scheme 41). If voltage is not within specification, check wiring circuit and individual component.

Scheme 38

Scheme 39

Scheme 40

Scheme 41

TURBO CONTROL SYSTEM

1. Warm engine to normal operating temperature. Shut engine off. Start engine and note if turbo actuator rod moves. On vehicles with Anti-Lock Brakes (ABS), it may be necessary to move air control valve and air silencer toward engine to gain access to actuator rod.
2. Disconnect Green turbo solenoid valve connector. Actuator rod should return. Reinstall valve connector. Increase engine speed and note that actuator rod starts to move at approximately 2700 RPM.

TURBO SOLENOID VALVE SIGNAL

Warm engine to normal operating temperature. Connect voltmeter to LT. BLU wire of solenoid valve. Increase engine speed and note voltage. Voltage should be within specification. See TURBO SOLENOID VALVE VOLTAGE table.

TURBO SOLENOID VALVE VOLTAGE

Information not available from manufacturer.

1. Intake air temperature sensor and fuel pump switch are contained in the airflow meter. Determine terminal identification. (Scheme 42)
2. Using ohmmeter, measure resistance between designated terminals. See «AIRFLOW METER RESISTANCE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. Reading must be within specification. AIRFLOW METER RESISTANCE Terminals Ohms Temperature E2 & Vs - Non-Turbo 50-500 N/A E2 & Vs - Turbo 200-600 N/A E2 & Vref - Non-Turbo 200-500 N/A E2 & Vref - Turbo 200-400 N/A E2 & THAa (1) 10,000-20,000 -4°F (-20°C) E2 & THAa (1) 4000-7000 32°F (0°C) E2 & THAa (1) 2000-3000 68°F (20°C) E2 & THAa (1) 900-1300 104°F (40°C) E2 & THAa (1) 400-700 140°F (60°C) E1 & Fc Infinity N/A (1) Intake air temperature sensor.
3. Ensure measuring plate moves freely in airflow meter. Remaining terminals must be checked for fuel pump switch and measuring plate resistances. (Scheme 42) Attach ohmmeter to specified terminals to check fuel pump switch and measuring plate resistance. See «FUEL PUMP SWITCH & PLATE RESISTANCE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table.

FUEL PUMP SWITCH & PLATE RESISTANCE

Scheme 42

Connect voltmeter to "D" terminal of atmospheric pressure sensor and ground. (Scheme 43) Turn ignition and note voltage. Voltage should be within specification. See ATMOSPHERIC PRESSURE SENSOR VOLTAGE table. Replace sensor if not within specification.

ATMOSPHERIC PRESSURE SENSOR VOLTAGE

Scheme 43

Boost Or Pressure Sensor

1. Disconnect vacuum hose from sensor. Connect voltmeter to "D" terminal. (Scheme 44) Using vacuum pump, apply 3.9 in. Hg to sensor.
2. Turn ignition on and note voltage reading. Voltage should be within 2.5-3.5 volts for non-turbo or 2.0-2.5 volts for turbo models. Replace sensor if not within specification.

Scheme 44

Remove connector from switch. Connect ohmmeter to switch terminals. Check that continuity exists with clutch pedal depressed and no continuity exists with pedal released. Replace switch if continuity is not correct.

1. Remove switch from radiator. Place switch in container of heated coolant with thermometer.
2. Connect ohmmeter to switch terminals. Note temperature at which continuity exists between switch terminals. Continuity should exist with coolant temperature at 59-66.2°F (15-19°C). Replace switch if not within specification.

1. Remove thermosensor. Place thermosensor in container of heated coolant with thermometer.
2. Connect ohmmeter to thermosensor terminals. Note resistance at specified temperatures. See «COOLANT THERMOSENSOR RESISTANCE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. Replace if not within specification.

COOLANT THERMOSENSOR RESISTANCE

1. Remove sensor connector. Note terminal identification. (Scheme 34) Using ohmmeter, check resistance at specified terminals. Resistance must be within specification. See «CRANK ANGLE SENSOR RESISTANCE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table.

CRANK ANGLE SENSOR RESISTANCE

Inhibitor Switch (Non-Turbo A/T)

Remove connector from switch. Connect ohmmeter to switch terminals "C" and "D". (Scheme 45) Continuity should exist with gearshift in Park and Neutral. No continuity should exist in all other ranges.

Scheme 45

Remove connector from switch. Connect ohmmeter to switch terminals. Check that continuity exists with transmission in Neutral and no continuity exists in all other ranges. Replace switch if continuity is not correct.

Power Steering Relay (Turbo)

1. Connect battery leads to proper terminals. (Scheme 46) Using ohmmeter, check for continuity at remaining terminals.
2. Continuity should exist with battery voltage applied and not exist with battery disconnected. Replace relay if necessary.

Scheme 46

1. Start engine and allow to idle. Remove connector from switch. Connect ohmmeter to switch terminals. Turn steering wheel from side to side and note continuity reading.
2. Continuity should exist with wheels turned but should not exist with wheel straight ahead. Replace switch if continuity is not correct.

1. To check system operation, turn ignition on. The "OVER HEAT EXH SYSTEM" light should activate. Start engine and light should go out.
2. Remove right seat and lift up floor mat. Disconnect heat hazard sensor connector. Connect jumper wire between connector terminals. Check that "OVER HEAT EXH SYSTEM" light activates.
3. To check heat hazard sensor, remove sensor. Wrap sensor and thermometer with aluminum foil to prevent oil penetration. Place thermometer and sensor in container of oil.
4. Connect test light and battery to sensor terminals. (Scheme 47) Heat oil and note temperature in the aluminum foil when the test light activates. Test light should activate when temperature reaches 221-239°F (105-115°C). Replace sensor if not within specification.

Scheme 47

Knock Sensor

Information not available from manufacturer.

See AIRFLOW METER under COMPONENT TESTING for test procedure.

Information not available from manufacturer.

Overdrive Switch

Information not available from manufacturer.

5th Gear Switch

Information not available from manufacturer.

Remove resistor connector. Note terminal identification. (Scheme 48) Using ohmmeter, check resistance at specified terminals. See VARIABLE RESISTOR RESISTANCE table. Replace resistor if not within specification.

Note. Idle mixture must be adjusted if variable resistor is replaced.

VARIABLE RESISTOR RESISTANCE

Scheme 48

Coil With Ignitor

See appropriate DISTRIBUTOR & IGNITION SYSTEMS article for test procedures.

1. On turbo models, remove intercooler. On all models, remove sensor connector. Connect ohmmeter to terminals "A" and "B". (Scheme 49) Open throttle valve and note resistance readings.
2. On non-turbo models, repeat procedure on terminals "A" and "C". Resistance readings must be within specification. See «THROTTLE SENSOR RESISTANCE»(/mazda/rx-7/fc-1985-1992/remont/testing-diagnostics/#cec-system) table. Install sensor connector. On turbo models, reinstall intercooler.

THROTTLE SENSOR RESISTANCE

Scheme 49

Turbo Solenoid Valve

1. Disconnect vacuum hoses from solenoid valve. Blow through port "B". (Scheme 50) Air should flow from air filter. Remove connector from solenoid valve.
2. Apply battery voltage and ground to proper terminals. (Scheme 50) Blow through port "B". Air should flow from port "A".

Scheme 50

1. Operate engine to normal operating temperature. With engine off, install Checker Light (49 F018 001) to the Green check connector. (Scheme 51)
2. Turn ignition on and note checker light. One light should activate on checker light. If none or both lights activate, remove cap and rotate throttle sensor adjusting screw until only one light activates. (Scheme 52)
3. If both lights are activated, rotate adjusting screw counterclockwise until one light activates. If no lights are activated, rotate adjusting screw clockwise until one light activates. Reinstall cap on adjusting screw.

Scheme 51

Scheme 52

RX7 Non-Turbo Wiring Diagram. Scheme 53

RX7 Turbo Wiring Diagram. Scheme 54

See also:
• TESTING
• SELF-DIAGNOSIS