1994 MAZDA MX-5 Compression

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 INDEX ............................. B- 2 OUTLINE .......................... B- 3 SPECIFICATIONS ................ B- 3 TROUBLESHOOTING GUIDE ........ B- 3 ENGINE TUNE-UP .................. 8- 5 PREPARATION ................... B- 5 ENGINE OIL ..................... B- 5 ENGINE COOLANT ............... B- 5 DRIVE BELT ..................... 8- 6 HLA TROUBLESHOOTING GUIDE . 8- 8 IGNITION TIMING. IDLE SPEED .... B- 8 COMPRESSION .................... 8-10 INSPECTION ..................... B-10 ON-VEHICLE MAINTENANCE ....... B-11 PREPARATION ................... B-11 TIMING BELT ..................... 8-12 CYLINDER HEAD GASKET ........ B-16 H LA ............................. 8-20 FRONT OIL SEAL ................. 8-24 REAR OIL SEAL .................. 8-26 REMOVAL ......................... 8-28 PROCEDURE .................... B-28 ENGINE STAND MOUNTING ......... 8-32 PREPARATION ................... 8-32 PROCEDURE .................... B-33 DISASSEMBLY ..................... B-35 PREPARATION ................... 8-35 AUXILIARY PARTS ............... 8-36 TIMING BELT ..................... 8-37 CYLINDER HEAD ................. 8-39 CYLINDER BLOCK (EXTERNAL PARTS) ............. 8-42 CYLINDER BLOCK .............. (INTERNAL PARTS) 8-44 .............. INSPECTION I REPAIR 8-47 ................... PREPARATION 8-47 ................. CYLINDER HEAD 8-47 .............. VALVE MECHANISM 8-48 ...................... CAMSHAFT B-51 HLA ............................. 8-53 ............... CYLINDER BLOCK B-53 .......................... OIL JET B-54 PISTON. PISTON RING. AND ..................... PISTON PIN 8-55 CONNECTING ROD .............. B-56 ................... CRANKSHAFT 8-57 BEARING ........................ 8-57 TIMING BELT ..................... 8-58 TENSIONER. IDLER .............. 8-58 TENSIONER SPRING ............. 8-58 PULLEY ......................... 8-58 ........................ ASSEMBLY 8-59 ................... PREPARATION 8-59 CYLINDER BLOCK (INTERNAL PARTS) .............. B-60 CYLINDER BLOCK (EXTERNAL PARTS) ............. B-65 CYLINDER HEAD ................. B-69 TIMING BELT ..................... 8-73 ............... AUXILIARY PARTS 8-77 ..... ENGINE STAND DISMOUNTING 8-81 .................... PROCEDURE 8-81 INSTALLATION ..................... 8-83 .................... PROCEDURE 843 45UOBX-001 Gartner Banana

B INDEX INDEX 1. Timing belt Removal / Installation ....... page 8-1 2 2. Cylinder head gasket Replacement .............. page 6-1 6 3. HLA Removal / Installation ....... page 8-20 4. Front oil seal Replacement .............. page 6-24 5. Rear oil seal Replacement .............. page 6-26 INTAKE MANIFOLD COMPRESSION INSPECTION, PAGE B-10 TIGHTENING TORQUE STANDARD: 1,255 kPa (1 2.8 k f/cm2, 182 psi)-300 rpm 19-25 Nm (1.9-2.6 kgfq 14--18 ft4bf) MINIMUM: 883 kPa (9.0 kgflcm 9 , 128 psi}-300 rpm TIGHTENING TORQUE 3946 Nm i3.9--4.7 kgf m, 29-33 ftdbf) DRIVE BELT ADJUSTMENT. PAG ENGINE OIL INSPECTION, SERVICE, SECTION D DEFLECTION mm (in) ENGINE COOLANT INSPECTION, 6. Engine Removal .................. page 8-28 Engine stand mounting ..... page 6-32 Disassembly .............. page 6-35 Inspection / Repair ......... page B-47 Assembly ................. page 559 Engine stand dismounting ... page 8-81 , Installation ................ page B-83 SERVICE, SECTION E DRIVE BELT ALTERNATOR PIS. PIS + AlC AlC NEW 55-7.0 (0.224.27) 8.&9.0{0.324.35] 8.0-9.0{0.324.35) USED 6.0-7.5 (0.24-0.29) 9.0-10.0{0.364.39) 9.0-10.0{0.364.39} LIMIT 8.0 (0.31) 11.5 (0.45) 11.5 (0.453 Gartner Banana

OUTLINE, TROUBLESHOOTING GUIDE OUTLINE SPECIFICATIONS Engine Item Tv~e BP DOHC Gasoline, 4-cvcle . . I -, Dis~lacement ml kc. cu inl I 1.840 (1.840. 11 2) I Cylinder arrangement and number Combustion chamber Valve system Bore x stroke mm {in) I 83.0 x 85.0 (3.27 x 3.35) I In-line, 4-cylinders Pentroof DOHC, belt-driven Com~ression ratio I 9.0 I Compression pressure kPa (kgf/cm2, psi)-rpm .- . 1 open (BTDCO) 1,255 {I 2.8, 182)-300 5 Valve timing TROUBLESHOOTING GUIDE tX Valve clearance Problem .. . -. . Difficult starting ' With System Selector (49 B019 9AO) test switch at SELF TEST. 45uo~x-003 Close (ATDCO) IN mm {in) EX mm {in) Poor idling Close (ABDCO) Open (BBDCO) 14 0: Maintenance-free 0: Maintenance-free Excessive oil consumption 48 56 Possible Cause Malfunction of engine-related components Burned valve Worn piston, piston ring, or cylinder Failed cylinder head gasket Malfunction of fuel system Malfunction of ignition system Malfunction of engine-related components Malfunction of HLA' Poor valve-to-valve seat contact Failed cvlinder head aasket Oil leakage I Refer to section D I I Remedy Malfunction of fuel system Malfunction of ignition system Oil working up Worn piston ring groove or sticking piston ring Worn piston or cylinder Oil working down Worn valve seal Worn valve stem or guide Page Replace Replace or repair Replace Refer to section F Refer to section G Replace Replace or repair Re~lace 8-48 B-53,55 B-1 6 B-20 B-50 B-1 6 Refer to section F Refer to section G Replace Replace or repair Replace Replace B-55 B-53,55 B-39,70 8-48 Gartner Banana

B TROUBLESHOOTING GUIDE Problem nsufficlent power 4bnormal combustion Engine noise Possible Cause Insufficient compression Malfunction of HLA' Compression leakage from valve seat Seized valve stem Weak or broken valve spring Failed cylinder head gasket Cracked or distorted cylinder head Stuck, damaged, or worn piston ring Cracked or worn piston Malfunction of fuel system Malfunction of ignition system Others Slipping clutch Dragging brakes Wrong size tires Malfunction of engine-related components Malfunction of HLA* Stuck or burned valve Weak or broken valve spring Carbon accumulation in combustion chamber Malfunction of fuel system Malfunction of ignition system Crankshaft- or bearing-related parts Excessive main bearing oil clearance Main bearing seized or heat-damaged Excessive crankshaft end play Excessive connecting rod bearing oil clearance Connecting rod bearing seized or heat-damaged Piston-related parts Worn cylinder Worn piston or piston pin Seized piston Damaged piston ring Bent connecting rod Valves or timing-related parts Malfunction of HLA' Broken valve spring Excessive valve auide clearance Malfunction of cooling system Malfunction of fuel system Others Malfunction of water pump bearing Improper drive belt tension Malfunction of alternator bearing Exhaust gas leakage Malfunction of timina belt tensioner Remedy Replace Repair Replace Replace Replace Replace Replace Replace Refer to section F Refer to section G Refer to section H Refer to section P Refer to section Q Replace Replace Replace Eliminate carbon Refer to section F Refer to section G Replace or repair Replace Replace or repair Replace or repair Replace Replace or repair Replace Replace Replace Replace Replace Replace Replace Refer to section E Refer to section F Refer to section E Adjust Refer to section G Refer to section F Replace Page Tappet noise may occur if the engine has set idle for an extended period. The noise should dissipate after the engine has reached normal operating temperature. (HLA troubleshooting: Refer to page 6-8) Gartner Banana

COMPRESSION COMPRESSION If the engine exhibits low power, poor fuel economy, or poor idle, check the following: 1. Ignition system (Refer to section G.) 2. Compression (Refer to page B-10.) 3. Fuel system (Refer to section F.) INSPECTION 1. Check that the battery is fully charged. Recharge it if necessary. (Refer to section G.) 2. Warm up the engine to the normal operating tempera- ture. 3. Turn the engine OFF. 4. Remove all spark plugs. 5. Disconnect the ignition coil connector. 6. Connect a compression gauge to the No.1 spark plug hole. 7. Fully depress the accelerator pedal and crank the en- gine. 8. Record the maximum gauge reading. 9. Check each cylinder, as above. Compression: 1,255 kPa (1 2.8 kgf/cm2, 182 psi)-300 rpm Minimum: 883 kPa (9.0 kgf/cm2, 128 psiF300 rpm Differential limit between cylinders: 196 kPa (2.0 kgf/cm2, 28 psi} 10. If the compression in one or more cylinders is low, pour a small amount of engine oil into the cylinder and re- check the compression. (1) If the compression increases, the piston, piston rings, or cylinder wall may be worn. (2) If the compression stays low, the valve may be stuck or seated improperly. (3) If the compression in adjacent cylinders stays low, the cylinder head gasket may be defective or the cyl- inder head distorted. 11 . Connect the ignition coil connector. 12. Install the spark plugs. Tightening torque: 15--22 N.m (1.5-2.3 kgf.m, 11-16 ftlbf) 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

F TROUBLESHOOTING GUIDE INSPECTION Check if battery positive voltage exists at fuel pump connector fuel pump positive terminal with jumper wire connected.(~tep 3 Check for fuel injector operating sound while crank- ing engine Check if battery positive voltage exists at fuel injector connector B terminal wire with ignition switch ON Connect data link connector terminals F/P and GND with jumper wire and check for correct fuel line pres- sure with ignition switch ON page F-110 Fuel Line pressure: 265--314 kPa f2.7-3.2 kgf/crn2, 38-46 psi) Check for correct engine compression Section B Engine compression: 1,255--883 kPa {12.&9.0 kgf/crn2, 182-1 28 psi)-300 rpm Check if spark plugs are OK WEAR AND CARBON BUILDUP BURNS PLUG GAP 1.0-l.lmm DAMAGE AND (0.040-0.043 in) DETERIORATION DAMAGE Try known good PCME and check if condition im- proves page F-144 - Yes - No Yes Yes - No Yes Yes - No - Yes ACTION Check continuity of fuel pump page F-114 Check fuel pump relay page F-117 Go to Step 7 Go to Step 6 Check PCME terminals 2A, 2U, 2V, 2Y and 22 voltages @3F page F-147 Check for open circuit in wiring between main relay and fuel injector page F-7 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 engine condition @3F Section B w Worn piston, piston rings or cylinder wall Defective cylinder head gasket w Distorted cylinder head Improper valve seating w Valve sticking in guide Go to next step Repair, clean, or replace Section G 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