1994 MAZDA MX-5 ad blue

ELECTRICAL PARTS GI BATTERY CABLE Before disconnecting connectors or removing electrical parts, disconnect the negative battery cable. CONNECTORS Data Link Connector Insert the probe into the service hole when connecting a jumper wire to the data link connector. Caution Inserting a jumper wire probe into the data link connector terminal may damage the terminal. Power Connector The special power connector in the engine compartment (Blue: 1 -pin) supplies battery positive voltage for exter- nally powered test equipment. Caution Do not ground the power connector terminal; the 20A wiper fuse will be burned. Disconnecting Connectors When disconnecting two connectors, grasp the connec- tors, not the wires. Connectors can be disconnected by pressing or pulling the lock lever as shown. Gartner Banana

ELECTRICAL PARTS GI SENSORS, SWITCHES, AND RELAYS Handle sensors, switches, and relays carefully. Do not drop them or strike them against other objects. kD YELLOW WIRING HARNESS Wiring color codes Two-color wires are indicated by a two-color code sym- bol. The first letter indicates the base color of the wire and the second the color of the stripe. IGI Green 11 R 1 Red I B BR COLOR FUSE Replacement 1. When replacing a fuse, be sure to replace it with one of the specified capacity. If a fuse again fails after it has been replaced, the circuit probably has a short and the wiring should be checked. 2. Be sure the negative battery terminal is disconnected before replacing a main fuse (80A). CODE CODE Black Brown GY L LB LG 3. When replacing a pullout fuse, use the fuse puller sup- plied in the fuse box cover. COLOR 0 P Gray Blue Light Blue Light Green Orange Pink V W Y - Violet White Yellow - Gartner Banana

ENGINE TUNE-UP HLA TROUBLESHOOTING GUIDE Problem 1. Noise when engine is started immediately af- ter oil is changed 2. Noise when engine is started after setting approx. one day 3. Noise when engine is started after cranking for 3 seconds or more 4. Noise when engine is started after new HLA is installed 5. Noise continues more than 10 minutes 5. Noise occurs during idle after high speed run- ning Possible Cause Oil leakage in oil passage Oil leakage in HLA Faulty HLA Action Run engine 2000-3000 rpm. If noise stops after 2 second-10 minutes(') HLA is normal. If not, replace HLA. Time required for engine oil to circulate withir engine, includes tolerance for engine oi condition and ambient temperature. Insufficient oil pressure (Refer to page 8-53) Press down HLA by hand. If it does not move, HLA is normal. If it moves, replace HLA. Check oil pressure. If lower than specification, check for cause. Oil pressure; 295-392 kPa I3.0-4.0 kgf/cm2, 43-56 psil-3000 rpm Deteriorated oil Check oil quality. If deteriorated, replace with specified type and amount of oil. Incorrect oil amount IGNITION TIMING, IDLE SPEED Preparation 1. Check the condition of the engine (spark plugs, leaks in hoses, etc.). 2. Make sure all accessories are OFF. 3. Warm up the engine to normal operating temperature. 4. Connect a timing light and a tachometer to the data link connector terminal IG-. When using an externally pow- ered timing light and/or tachometer, connect it to the power connector (Blue: 1 -pin). Measure valve clearance. If more than Omm {0 in}, replace HLA. Check oil level. Drain or add oil as necessary. Caution Grounding the power connector terminal (Blue: 1-pin) will burn out the 20A wiper fuse. 5. Make sure coolant fan does not operate. Gartner Banana

INSPECTION 1 REPAIR Valve Seat 1. lnspect the contact surface of each valve seat and valve face for the following: (1) Roughness u (2) Damage 2. If necessary, resurface the valve seat with a 45" valve seat cutter andlor resurface the valve face. 3. Apply a thin coat of Prussian blue to the valve face. 4. lnspect the valve seating by pressing the valve against the seat. (1) If blue does not appear 360" around the valve face, replace the valve. (2) If blue does not appear 360" around the valve seat, resurface the seat. 5. Measure the seat contact width. Width: 0.8-1.4mm (0.032-4.055 in) 6. Verify that the valve seating position is at the center of the valve face. (1) If the seating position is too high, correct the valve seat with a 70" cutter and a 45" cutter. (2) If the seating position is too low, correct the valve seat with a 0° cutter and a 45" cutter. 7. Seat the valve to the valve seat with lapping compound. 8. lnspect the sinking of the valve seat. Gartner Banana

TROUBLESHOOTING GUIDE SYMPTOM TROUBLESHOOTING 2 CRANKS NORMALLY BUT WILL NOT START (NO COMBUSTION) Engine cranks at normal speed but shows no sign of "firing" ESCwPTION : Battery in normal condition Throttle valve not held wide open throttle while cranking Fuel in tank rROUBLESHOOTlNG HINTS] ecause of no combustion, possibly no fuel is injected to engine or no ignition at all cylinders 1 No spark O Low fuel line pressure lanition control malfunction @ Low engine compression ignition system component malfunction I No fuel injection Fuel pump does not operate Fuel injector does not operate INSPECTION ACTION :heck if strong blue spark is visible at disconnected iigh-tension lead while cranking engine :heck if "00" is displayed on Self Diagnosis Checker ~ith ignition switch ON page F-79 Sonnect data link connector terminals F/P and GND ~ith jumper wire and check for fuel pump operating sound with ignition switch ON page F-114 Yes - No - Yes No - Yes - No Go to Step 3 Go to Step 2 Check ignition system (Refer to Troubleshooting "Misfire") mf Section G Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage ojg. page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME us? page F-143 Q If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Check if engine starts in this condition 0 If starts, check fuel pump relay f@ page F-117 r3 If does not start, go to Step 5 Go to Step 4 Gartner Banana

TROUBLESHOOTING GUIDE 3 CRANKS NORMALLY BUT WILL NOT START (PARTIAL COMBUSTION) -WHEN ENGINE IS COLD Engine cranks at normal speed but shows partial combustion and will not continue to run IESCRIPTION Battery in normal condition Fuel in tank TROUBLESHOOTING HINTS] B AirIFue! mixture too rich Q Low engine compression Air cleaner element clogged D AirIFuel mixture too lean Fuel injection control malfunction (Correction for coolant temperature) Low fuel line pressure Air leakage of intake air system 1 INSPECTION ACTION :heck if "00" is displayed on Self-Diagnosis Checker ~ith ignition switch ON as page F-79 Sheck if strong blue spark is visible at each discon- iected high-tension lead while cranking engine Connect data link connector terminals F/P and GND with jumper wire and check for correct fuel line pres- sure with ignition switch ON E+T page F-110 Fuel Line pressure: 265--314 kPa I2.7-3.2 kgf/cm2, 38-46 psi) INSTALL CLAPS ' Yes Yes Yes - No - Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage @f page F-145 Specification: Battery positive voltage (Ignition switch ON) O If OK, replace PCME page F-143 L:, If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Check ignition system (Refer to Troubleshooting "Misfire") Section G Go to next step Low pressure Check fuel line pressure while pinching fuel return hose If fuel line pressure quickly increases, check pressure regulator page F-118 o If fuel line pressure gradually increases, check for clog- ging between fuel pump and pressure regulator If not clogged, check fuel pump maximum pressure page F-115 High pressure Check if fuel return hose is clogged or restricted O If OK, replace pressure regulator page F-119 s If not OK, repair or replace Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION ACTION Check if PCME terminal voltages are OK (1 R, 1 T, ZD, 20 and 20) us page F-146 Yes Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") Djp paae F-148 Check if strong blue spark is visible at each discon. nected high-tension lead while cranking engine Yes - No Go to next step Check ignition system (Refer to Troubleshooting "Misfire") Section G Check for EGR system malfunction page F-124 Yes - No Repair or replace Go to next step Check for fuel injector operating sound at each in- Yes Go to Step 10 jector at idle No - Yes Go to Step 9 Check if battery positive voltage exists at fuel injec- tor connector B terminal with ignition switch ON Check if fuel injector resistance is OK page F-119 Resistance: 12-1 6R G If OK, check wiring between injector and PCME page F-7 o If not OK, replace injector L@? page F-119 No - Yes Check wiring between main relay and fuel injector page F-7 Go to next step Check for correct engine compression Section B Engine compression: 1,255-883 kPa I12.8-9.0 kgflcm2, 182-1 28 psi)-300 rpm Check engine condition Section B I Worn piston, piston rings or cylinder wall r Defective cylinder head gasket r Distorted cylinder head r Improper valve seating Valve sticking in guide No - Yes :heck if spark plugs PLUG GAP 1 .O-1 .l mm (0.04+0.043 in} DETERIORATION 30 to next step qepair, clean, or replace Section G Try known good PCME and check if condition im- roves @r page F-144 Gartner Banana

F TROUBLESHOOTING GUIDE INSPECTION :heck for correct intake manifold vacuum at idle Vacuum: More than 450 mmHg I17.7 inHg) VACUUM GAUGE :heck if PCME terminal voltages are OK (2D, 20 and 2Q) page F-146 :heck for correct ignition timing at idle @S page F-76 Ignition timing: 10" + 1" BTDC :heck for correct fuel line pressure at idle @S page F-11 0 Fuel line pressure: 265--314 kPa f2.7-3.2 kgf/cm2,38-46 psi} (Vacuum hose to pressure regulator discon- INSTALL CLAPS ' :heck if strong blue spark is visible at each discon- iected high-tension lead while cranking engine - -- :heck for correct engine compression @S Section B Engine compression: 1,255-883 kPa (12.8-9.0 kgf/cm2, 182-128 psi)-300 rpm - Yes Yes Yes No - Yes - No - Yes No - Yes - No - ACTION Go to next step Low vacuum Check for air leakage of intake air system components page F-100 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") page F148 Check for correct idle speed page F77 Idle speed: 850 -c 50 rpm (Mi) 800 + 50 rpm (AT) e If OK, go to next step o If not OK, adjust idle speed page F-77 Adjust page F-76 Go to next step Low pressure Check fuel line pressure while pinching fuel return hose 0 If fuel line pressure quickly increases, check pressure regulator page F-118 0 If fuel line pressure gradually increases, check for clog- ging between fuel pump and pressure regulator If not clogged, check fuel pump maximum pressure page F-115 Go to next step Check ignition system (Refer to Troubleshooting "Misfire") Section G Go to next step Check engine condition Section B Worn piston, piston rings or cylinder wall Defective cylinder head gasket Distorted cylinder head Improper valve seating Valve sticking in guide Gartner Banana