1994 MAZDA MX-5 Workshop Manual

CONTROL SYSTEM SENSOR CONNECTOR EATED OXYGEN Specification Fully closed: 0.1-1.1 V Fully open: 3.14.5V (Verify that the voltage increase is directly d propotioned to the throttle valve opening angle.) 8. Tighten the attaching screws. Tightening torque: 1.6-2.3 N.m (16-24 kgfmm, 14-20 in-lbf} 9. If not adjusted, replace the throttle position sensor. 45UOFX-495 Replacement 1. Turn the ignition switch OFF. 2. Remove the throttle position sensor screws. 3. Remove the throttle position sensor . 4. Replace a new throttle position sensor and adjust it. (Refer to page F-155.) 5. Tighten the throttle position sensor screws. Tightening torque: 1.6-2.3 N.m (16-24 kgf-cm, 14-20 in-lbf} HEATED OXYGEN SENSOR Inspection On-vehicle 1. Warm-up the engine to normal operating temperature and run it at idle. 2. Disconnect the heated oxygen sensor connector. -.-' 3. Measure the voltage at terminal A. 4. If not as specified, check the intake air system, the fuel system and run the on-board diagnosis test. 5. If these system are OK, replace the heated oxygen sen- sor. Specification Heater 1. Disconnect the heated oxygen sensor connector. 2. Measure resistance between terminals C and D. Resistance: Approx. 13R (20°C (68°F)) Engine condition Terminal A 3. Replace the heater if not as specified. Increasing engine speed (V) 0.&1 .O Idle Below 1.0 Replacement 1. Disconnect the heated oxygen sensor connector. 2. Remove the heated oxygen sensor. 3. Install in the reverse order of removal. Decreasing engine speed (V) 0-0.4 Tightening torque: 3049 N-m (3.0-5.0 kgf-m, 22-36 ftlbf) Gartner Banana

CONTROL SYSTEM LOCK 4. If not as specified, replace the main relay. MAIN RELAY lnspection 1. Verify that the main relay clicks when turning the ignition switch OFF -+ ON. 2. Apply battery positive voltage to terminal A and ground terminal B of the main relay. 3. Use an ohmmeter to check continuity of the terminals as shown. CLUTCH SWITCH Inspection 1. Disconnect the clutch switch connector. 2. Connect an ohmmeter to the switch. 3. Check continuity of the switch. Battery positive voltage applied - Continuity - Terminals CD L 4. If not as specified, replace the clutch switch. Battery positive voltage not applied No continuity Pedal Depressed Released Replacement 1. Disconnect the clutch switch connector. 2. Loosen the locknut. 3. Remove the clutch switch. 4. Install in the reverse order of removal. 5. Adjust the pedal height. (Refer to Section H.) Continuity Yes No 4. If not as specified, replace the neutral switch. NEUTRAL SWITCH lnspection 1. Disconnect the neutral switch connector. 2. Connect an ohmmeter to the switch. 3. Check continuity of the switch. Transmission Neutral Other ranges Continuity , Yes No Gartner Banana

CONTROL SYSTEM Replacement Replace the neutral switch as shown in the figure. STEERING PRESSURE SENSOR Inspection 1. Disconnect the steering pressure sensor connector. 2. Connect an ohmmeter to the switch. 3. Start the engine and let it idle. Check continuity of the switch while turning the steering wheel. PIS 1 Continuity Turnina Yes " I t ~ot turning I NO 4. If not as specified, replace the steering pressure sensor. Replacement Replace the steering pressure sensor as shown in the figure. Gartner Banana

Before beginning any service procedure. refer to section T of this manual for air bag system service warnings and audio antitheft system alarm conditions . ENGINE ELECTRICAL SYSTEM INDEX ....................................... G- 2 OUTLINE ..................................... G- 3 SPECIFICATIONS ........................... G- 3 TROUBLESHOOTING GUIDE .................. G- 4 CHARGING SYSTEM .......................... G- 6 PREPARATION ............................. G- 6 CIRCUIT DIAGRAM ......................... G- 6 TROUBLESHOOTING ....................... G- 7 BATTERY .................................. G- 8 ALTERNATOR .............................. G-10 DRIVE BELT ................................ G-13 IGNITION SYSTEM ............................ G-15 PREPARATION ............................. G-15 CIRCUIT DIAGRAM ......................... G-15 TROUBLESHOOTING ....................... G-16 IGNITION TIMING ........................... G-17 SPARK PLUG ............................... G-18 IGNITION COIL ............................. G-19 IGNITER ................................... G-19 HIGH-TENSION LEAD ....................... G-20 STARTING SYSTEM ........................... G-21 CIRCUIT DIAGRAM ......................... G-21 TROUBLESHOOTING ....................... G-21 STARTER .................................. G-22 STARTER INTERLOCK SWITCH (MT) ......... G-28 45UOGX401 Gartner Banana

G INDEX INDEX 1. Battery lnspection . . . . . . . . . . . . . . . . . page G- 8 Recharging . . . . . . . . . . . . . . . . page G- 9 Replacement . . . . . . . . . . . . . . page G-10 2. Alternator Removal / lnstallation . . . . . . . page G-10 Disassembly / Assembly . . . . page G-11 lnspection . . . . . . . . . . . . . . . . . page G-12 3. Drive belt lnspection . . . . . . . . . . . . . . . . . page G-13 Adjustment . . . . . . . . . . . . . . . . page G-14 4. Spark plug Removal / Installation . . . . . . . page G-18 Spark test . . . . . . . . . . . . . . . . . page G-18 lnspection . . . . . . . . . . . . . . . . . page G-18 5. Ignition coil lnspection . . . . . . . . . . . . . . . . . page G-19 Replacement . . . . . . . . . . . . . . page G-19 6. Igniter (in ignition coil) lnspection . . . . . . . . . . . . . . . . . page G-19 7. High-tension lead Removal / lnstallation . . . . . . . page G-20 lnspection . . . . . . . . . . . . . . . . . page G-20 8. Starter Removal / lnstallation . . . . . . . page G-22 Performance lnspection . . . . . page G-23 Disassembly / Assembly . . . . page G24 -' lnspection . . . . . . . . . . . . . . . . . page G26 9. Starter interlock switch (MT) lnspection . . . . . . . . . . . . . . . . . page G-28 Gartner Banana

OUTLINE OUTLINE SPECIFICATIONS (i.e. powertrain control module (engine), audio, etc.) *2 With System Selector (49 B019 9AO) test switch at SELF TEST. - Engine Item Starter Ignition system Cylinder Arrangement Battery BP DOHC MT I AT 12, Negative ground S46A24L(S) (32 Ah) Maintenance-free 20.0 A.C. I REAR Voltage V Type and capacity (5-hour rate) 12-65 -. 1 2-70 Drive belt deflection mm {in} Dark current" m A Transistorized (built-in voltage regulator) 14.3-1 4.9 21.5 I0.846) 8 (0.31 1 Ignition timing** BTDC ("CA)lrpm U Alternator 'I Dark current is the constant flow of current while the ignition switch is OFF. 45UoGX-003 New Used 101850 Ignition coil Spark plug FRONT 55-7.0 (0.22-0.27) 6.0-7.5 (0.2H.29) 101800 TY pe Primary coil winding n Secondary coil winding kR Type Plug gap mm {in) Firing order Type Output V-A Regulator type Regulated voltage V TY pe Output V-kW Molded (with igniter) - 8.7-1 2.9 (20°C (68°F)) NGK : BKR5E-11 BKR6E-11 (Standard ... MT) NIPPONDENSO : K16PR-U11 K20PR-U11 (Standard ... MT, AT) 1 .O-1.1 IO.040-0.043) 1-3-4--2 Brush length mm {in) Direct 124.95 17.0 i0.67) 11.5 I0.45) Brush length mm {in} Standard Minimum Coaxial reduction 12-1.4 17.5 i0.69) 12.0 i0.47) Standard Minimum Electronic spark advance (ESA) Powertrain control module (engine) controls spark advance Type Spark advance control Gartner Banana

TROUBLESHOOTING GUIDE TROUBLESHOOTING GUIDE Problem Will not crank Cranks slowly Discharged battery Misfire G-5 Will not crank I Will not crank I Check 1 1 , YES, Check if engine cranks with fully charged battery Check charging system (Refer to page G-7) I NO Check ignition switch (Refer to section T), starter interlock switch (Refer to page G-28) and parWneutral switch (Refer to section K) 45uOOx-OC - Check 1 Check if click is heard from starter magnetic switch when ignition is turned to START Cranks slowly Check starting system (Refer to page G-21) Crank slowly Check 1 Check charging system (Refer to page G-7) I NO ---- Check starting system (Refer to page G-21) Check 1 Gartner Banana

TROUBLESHOOTING GUIDE G Discharged battery I Misfire L Misfire Check ignition system (Refer to page G-16) Discharged battery Check charging system (Refer to page G-7) 05UffiX-006 Gartner Banana