1994 MAZDA MX-5 sensor

CONTROL SYSTEM 1 1 USE CONNECTOR A CRANKSHAFT POSITION SENSOR Inspection 1. Remove the crankshaft position sensor 5v- - - - SGGSIGNAL ov Warning Disconnect the fuel injector connector. When checking the crankshaft position sensor, do not connect the igniter connector - - - - I 1 CYCLE < > 2. Connect the crankshaft position sensor shown in figure. 3. Disconnect the fuel injector connector. 4. Turn the ignition switch ON. 5. Connect the SSTs (Engine Signal Monitor and Adapter Harness) to the PCME. 6. Set the SST (Engine Signal Monitor) as shown below. 7. Rotate the sensor drive by hand and measure the output voltage. Specification I 1 - Position - ~oltaael 8. After the inspection, install the crank angle sensor. 9. Start the engine and adjust the ignition timing. (Refer to page F-76.) 2E (SGT signal) 2G (SGC signal) Ignition timing: BTDC 10 2 1" Approx. 5V (4 pulseslrev) Approx. 5V (2 pulseslrev) 10. Tighten the crank angle sensor lock bolt to the specified torque. Tightening torque: 19-25 N-m (1 .+2.6 kgfem, 14-1 8 ftelbf} Replacement 1. Remove the ignition coil. (Refer to section G.) 2. Remove in the order shown in the figure. 3. Install in the reverse order of removal. Gartner Banana

CONTROL SYSTEM TEMPERATURE NGlNE COOLANT EMPERATURE ENGINE COOLANT TEMPERATURE SENSOR Removal 1. Remove the ignition coil assembly. (Refer to section G.) 2. Disconnect the engine coolant temperature sensor con- 4 nector. 3. Remove the engine coolant temperature sensor. lnspection 1. Place the sensor in water with a thermometer and heat the water gradually. 2. Measure resistance of the sensor with an ohmmeter. 3. If not as specified, replace the engine coolant tempera- ture sensor. Specification DCBA Coolant 20°C {68"F) 80°C {I 76°F) FEELER GAUGE Resistance kR 2.21 - 2.69 0.287- 0.349 Installation 1. Install the engine coolant temperature sensor and a new washer. Tightening torque: -J 25-29 N.m (2.5-3.0 kgf-m, 19--21 ft-lbf) 2. Connect the engine coolant temperature sensor con- nector. 3. Install the ignition coil assembly. (Refer to section G.) THROTTLE POSITION SENSOR lnspection Idle switch 1. Turn the ignition switch OFF and the throttle valve closed throttle position. 2. Disconnect the throttle position sensor connector. 3. Check continuity of the throttle position sensor terminals C and D. I C-D I Continuity 4. If not as specified, adjust the throttle position sensor. (Refer to page F-155.) 5. Insert a feeler gauge 0.4 mm {0.016 in) between the stopper and the throttle lever. 6. Verify that no continuity the throttle position sensor ter- minals C and D. - 7. If continuity, adjust the throttle position sensor. (Refer to page F-155.) Specification Terminals Throttle valve closed throttle ~osition Gartner Banana

CONTROL SYSTEM DCB IIIf I 1 USECONNECTORA I Variable resister 1. Remove the PCME. (Refer to page F-143.) 2. Connect the SSTs (Engine Signal Monitor and Adapt- er Harness) to the PCME. 3. Set the SST (Engine Signal Monitor) to position 2M. 4. Turn the ignition switch ON. 5. Rotate the throttle link by hand and verify that voltage is within the specification. Specification 6. If not as specified, adjust the throttle position sensor. (Refer to below.) - PCME terminal Adjustment Throttle valve position I Wide open throttle ~osition Note The throttle adjusting screw is set at the factory and must not be adjusted. Any adjustment will negatively effect the engine per- formance. Idle switch 1. Turn the ignition switch OFF and the throttle valve closed throttle position. 2. Disconnect the throttle position sensor connector. 3. Loosen the throttle position sensor screws. 4. Rotate the throttle position sensor and adjust continuity of the sensor terminals C and D as shown. Specification I Clearance Continuity I 5. Tighten the throttle position sensor screws. 0.3 mm (0.012 in} Tightening torque: 1.6-2.3 N.m (16-24 kgf-m, 14--20 in-lbf) Yes Variable resister 1. Remove the PCME. (Refer to page F-143.) 2. Connect the SSTs to the PCME connector as shown. 3. Verify that the throttle valve is fully closed. 4. Loosen the attaching screws. 5. Turn the ignition switch to ON. 6. Measure the PCME terminal 2M voltage. 7. Adjust the voltage to the specification 0.4 mm (0.01 6 in) I No Gartner Banana

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 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

CHARGING SYSTEM B TE S TERMINAL 1. Remove the battery cover. 2. Disconnect the battery cable from the battery. 3. Remove the battery from the vehicle. 4. Place the battery in a pan of the water to prevent it from ,-, over heating, but keep water away from the top of bat- tery. 5. Charge the battery. Replacement Note When replacing the battery, replace it with the same style Mazda genuine battery (with vent manifold). ALTERNATOR Caution Obtain the code number and deactivate the audio anti-theft system before disconnecting the bat- tery. (Refer to section T.) Caution Reversing the battery connections or using high- voltage testers will damage the rectifier. Caution Do not start the engine while the connector is dis- connected from L and S terminals. It can damage the alternator. Note .--,' Positive voltage is always present at alternator B ter- minal. Removal l Installation 1. Disconnect the negative battery cable. 2. Disconnect the steering pressure sensor connector. 3. Disconnect the water thermoswitch connector. 4. Disconnect the IAC valve connector. 5. Remove the intake air pipe. 6. Disconnect the wire and connector from the alternator. 7. Remove the alternator bolts and nut. 8. Remove the alternator. 9. Install in the reverse order of removal. Tightening torque Bolt 0: 38-51 N.m (3.8-5.3 kgf-m, 27-38 ftelbf) Bolt @ : 19-25 N.m j1.9-2.6 kgfem, 14--18 ft-lbf) Nut @I: 9.9--14 N.m (100-150 kgf-cm, 87-1 30 in-lbf) Gartner Banana

IGNITION SYSTEM G IGNITION SYSTEM f PREPARATION b SST r I I 49 BO19 9AO For inspection of System ignition timing selector CIRCUIT DIAGRAM CRANKSHAFT POSITION SENSOR SIGNAL w 9 c PCME 3 IGNITION COlL (WITH IGNITER) IGNITION COlL TO (WITH IGNITER) SPARK PLUG I I I 6'5) IGT2 SIGNAL 1 IGNITER - GND 3 1 h - - CRANKSHAFT POSITION SENSOR IGNITION COIL u Note If a timing light is used to check for spark, some lights do not light at Nos.2 and 4 cylinders even if the ignition system is normal. Gartner Banana

IGNITION SYSTEM TROUBLESHOOTING Misfire I 1 Check 1 NO NO 1. Turn ignition switch ON 2. Connect data link connector terminals (TEN) and (GND) with a jumper wire 3. Check if MIL illuminates I Check if resistance of secondary windings is OK Replace ignition coil (Refer to page G-19) (Refer to page G-19) I Refer to section F Check 2 Check if resistance of Replace high-tension lead (Refer to page G-20) (Refer to page G-20) I I Check 3 Check if spark plug is OK ( I Check 4 1 YES I Check PCME terminals (Refer to section F) a 1 G, 1 H (Igniter) 0 2E, 2G (Crankshaft position sensor) Repair or replace (Refer to section F) ( 2F, 20 ass airflow sensor) YES Replace ignition coil (igniter malfunction) 1 Check 1 Check 3 Check 2 PLUG WEAR AND CARBON BUILDUP BURNS DAMAGE AND DETERIORATION DAMAGE Gartner Banana