battery MAZDA MX-5 1994 Repair Manual

TROUBLESHOOTING GUIDE 3ESCRIPTION ( Engine unexpectedly stops running while decelerating or after deceleration JROUBLESHOOTING HINTS] Ingine speed drops too much when releasing accelerator D Idle speed control malfunction Q Engine feedback control malfunction D Fuel cut control malfunction @ Idle speed misadjustment 19 INSPECTION :heck if "00" is displayed on Self-Diagnosis Check- 3r with ignition switch ON page F-79 ENGINE STALLS ON DECELERATION >heck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A MONITOR kt \A SYSTEM SELECT 1 Disconnect heated oxygen sensor connector and :heck if condition improves >heck if PCME terminal voltages are OK [2D, 20,2U, 2V 2Q, 2Y and 22) its page F-146 - Yes - No Yes Yes No - Yes ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page Fa1 "88" flashes Check PCME terminal 1 E voltage us? page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME page F-143 o If not OK, check wiring between PCME and Self-Diagno. sis Checker page F-7 Go to'next step Lamp not ONJOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Check heated oxygen sensor @Tage F-156 Go to next step Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") E%= page F-148 Gartner Banana

TROUBLESHOOTING GUIDE DESCRIPTION I : Engine unexpectedly stops running at idle when AIC, PIS, or EIL ON AX, PIS, headlight, blower fan and electric coolant fan OK 20 [TROUBLESHOOTING HINTS] O ldle speed control malfunction No input signal from switch ldle speed misadjustment ldle air control valve stuck ENGINE STALLS AT IDLE - WHEN AIC, PIS, OR EIL ON INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON * page F-79 SELECT SW A SYSTEM SELECT 1 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON tw page F-95 SELECT SW A Check if PCME terminal voltages are OK (IG, 1 P, 1 U, 2D,2Q and 2W) page F-146 Check for correct idle speed page F-77 ldle speed: 850 2 50 rpm (MT) 800 2 50 rpm (AT) GND TEN 1 AIR ADJUSTING SCREW CONNECT TERMINAL - Yes - No Yes - No Yes - No Yes - No Go to next step ACTION Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page F-81 "88" flashes Check PCME terminal 1 E voltage page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME page F-143 s If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker IS page F-7 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") page F-148 Go to next step Adjust page F-77 Gartner Banana

TROUBLESHOOTING GUIDE DESCRIPTION I Engine intermittently stops running Before stallina, ennine condition OK 21 [TRO~ESHOOTING HINTS] O Intermittently no spark or no fuel injection Poor connection in wiring harness ENGINE STALLS SUDDENLY (INTERMITTENT) INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 Tap, move, and wiggle harness and connectors to check if PCME terminal voltages are OK (1 B, 2A, 2B and 2C) @ page F-146 ACTION Go to next step Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) @S page F-81 When checking wiring harness and connectors, tap, move, and wiggle suspect sensor and/or harness to recre- ate problem "88" flashes Check PCME terminal 1 E voltage @S page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME page F-143 0 If not OK, check wiring between PCME and Self-Diagno- sis Checker IS= page F-7 Go to Troubleshooting No.2 "CRANKS NORMALLY BUT WILL NOT START (NO COM- BUSTION)" page F-17 Check for cause (Refer to "Check Point for Each Termi- nal") page F-148 Gartner Banana

TROUBLESHOOTING GUIDE F b AirIFuel mixture leaning when depressing accelerator Fuel injection control malfunction (Correction for accelerating condition) Air leakage of intake air system Fuel line Pressure low 22 park adbance control malfunction HESITATESISTUMBLES ON ACCELERATION 0 - STEF DESCRIPTION] Flat spot occurs just after accelerator depressed or mild jerking occurs during acceleration rrROUBLESHOOTlNG HINTS] ACTION INSPECTION Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 SELECT SWA SYSTEM SELECT 1 - Yes Go to next step No - Yes - No Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) uz page F-81 "88'1 flashes Check PCME terminal 1 E voltage page F-145 Specification: Battery positive voltage (Ignition switch ON) 6 If OK, replace PCME page F-143 Q If not OK, check wiring between PCME and Self-Diagno- sis Checker US page F-7 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON Go to next step page F-95 SELECT SW A Lamp not ON/OFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker page F-7 Disconnect heated oxygen sensor connector and :heck if condition improves Yes - No - Yes -- -- Check heated oxygen sensor @s page F-156 Go to next step - :heck if PCME terminal voltages are OK :2M, 20, and 2Q) page F-146 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") page F-148 Gartner Banana

TROUBLESHOOTING GUIDE PROUBLESHOOTING HINTS] 3 Air/Fuel mixture too lean or too rich Fuel injection control malfunction Air leakage of intake air system 23 Fuel line pressure low Fuel evaporative malfunction 0 Spark advance control malfunction -- SURGES WHILE CRUISING - STEP DESCRIPTION ( Unexpected change in engine speed which is usually repetitive INSPECTION ACTION - Yes - No - Yes - No Check if "00" is displayed on Self-Diagnosis check- er with ignition switch ON page F-79 Go to next step SELECTSW A SYSTEM SELECT 1 Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequence) page ~-81 -- - "88" flashes Check PCME terminal 1 E voltage @i= page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME @ page F-143 o If not OK, check wiring between PCME and Self-Diagno- sis Checker US page F-7 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition Go to next step switch ON w page F-95 SELECT SW A Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker @ page F-7 Disconnect heated oxygen sensor connector and check if condition improves Yes No - Yes Check heated oxygen sensor page F-156 Go to next step :heck if PCME terminal voltages are OK (1 R, 1 T, 2M, 20, and 2Q) as page F-146 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") * page F-148 Gartner Banana

TROUBLESHOOTING GUIDE F 24 Overloaded ) Low intake air amount Throttle valve not oDen fully LACK OF POWER ESCRIPmH - TEP - 1 - 2 : Performance poor under load Reduced maximum speed :heck factors other than engine Clutch slipping as Section H Brake dragging Section P Low tire pressure as Section Q Unrecommended tire size Section Q ;heck if throttle valve wide open throttles when lepressing accelerator fully rROUBLESHOOTlNG HINTS] Factors other than engine malfunction O AirlFuel mixture too lean or too rich Clutch slipping Fuel line pressure low or high Brake dragging Insufficient fuel injection Low tire pressure @ Poor ignition Unrecommended tire size 8 Low engine compression >heck if "00 is displayed on Self-Diagnosis Check- !r with ignition switch ON page F-79 :heck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON as page F-95 SELECT SW A YSTEM SELECT 1 - Yes Yes Clogged intake air system - INSPECTION I - C 0 0 0 0 - c C - ( E -- I I i I I No - Yes No - Yes - No ACTION %to next step 20 to next step Sheck if accelerator cable is correctly installed page F-103 3 If OK, check throttle body @r page F-101 3 If not OK, install accelerator cable correctly page F-103 - 30 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 @r page F-145 Specification: Battery positive voltage (Ignition switch ON) o If OK, replace PCME page F-143 O If not OK, check wiring between PCME and Self-Diagno- sis Checker E+T page F-7 Go to next step -- Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker @r page F-7 Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION ACTION :heck for correct intake manifold vacuum at idle Iacuum: More than 450 mmHg i17.7 inHg} VACUUM GAUGE / :heck if air cleaner element is clean page F-76 Check for fuel injector operating sound at idle Check if battery positive voltage exists at fuel injec- tor connector B terminal Check if PCME terminal voltages are OK (1 R, 1 T, 2D, 20 and 2Q) page F-146 Check for correct fuel line pressure at idle page F-110 Fuel line pressure: 265--314 kPa i2.7-3.2 kgf/cm2, 38-46 psi) (Vacuum hose to pressure regulator discon- nected) INSTALL CLAPS Yes - No Yes - No - Yes No - Yes Yes No - Yes - No Go to next step -- - --- Check for air leakage of intake air system components r@= page F-100 Go to next step Replace air cleaner element ~8 page F-99 Go to Step 14 Go to Step 13 check if fuel injector resistance is OK page F-119 Resistance: 12-16R 6 If OK, check wiring between PCME and fuel injector E+Y page F-7 6 If not OK, check fuel injector for fuel leakage page F-120 Check wiring between PCME and fuel injector page F-7 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") page F-148 Check if fuel line pressure decreases when accelerating quickly c:, If decreases, check fuel pump maximum pressure @r page F-115 If OK, check fuel line and filter for clogging o If no decreases, go to next step Low pressure Check fuel line pressure while pinching fuel return hose ~2 If fuel line pressure quickly increases, check pressure regulator I@= page F-118 o If fuel line pressure gradually increases, check for clog- ging between fuel pump and pressure regulator r@= page F-119 If not clogged, check fuel pump maximum pressure page F-115 Gartner Banana

TROUBLESHOOTING GUIDE TROUBLESHOOTING HINTS] D Factors other than engine malfunction Clutch slipping Brake dragging Low tire pressure Unrecommended tire size 25 O AirIFuel mixture too lean or too rich Fuel line pressure low or high Insufficient fuel injection @ Poor ignition 6 Low engine compression POOR ACCELERATION Overloaded D Low intake air amount Throttle valve not open fully Clogged intake air system )ESCRIPTION I Performance poor while accelerating INSPECTION :heck factors other than engine Clutch slipping Section H D Brake dragging Section P t Low tire pressure Section Q D Unrecommended tire size Section Q :heck if throttle valve wide open throttles when jepressing accelerator fully Check if "00" is displayed on Self-Diagnosis Check- er with ignition switch ON page F-79 Check switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A SYSTEM SELECT 1 - Yes - No Yes - No - Yes - No Yes - No ACTION Go to next step Repair Go to next step Check if accelerator cable is correctly installed * page 0 If OK, check throttle body ce Page 0 If not OK, install accelerator cable correctly page Go to next step -- Diagnostic Trouble Code No. displayed Check for cause (Refer to specified check sequenc US page "88" flashes Check PCME terminal 1 E voltage Us Page Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME * Page 9 If not OK, check wiring between PCME and Self- sis Checker * Page Go to next step Lamp not ONlOFF with specified switch Check for cause (Refer to specified check sequenc * Paw Lamp always ON Check wiring between PCME terminal 1 D and Self nosis Checker * Page ! F-103 ! F-101 I F-103 :e) r F-81 ! F-145 I F-143 Diagno- ! F-7 :e) ! F-96 -Diag- ! F-7 Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION Sheck if air cleaner element is clean page F-76 1 :: :heck for EGR system malfunction Yes page F-124 Check for fuel injector operating sound at idle Yes Check if battery positive voltage exists at fuel injec- Yes tor connector B terminal Check if PCME terminal voltages are OK [I B, 1 T, 2D, 20 and 2Q) Check for correct fuel line pressure at idle Yes @T page F-110 Fuel line pressure: 265-314 kPa (2.7--3.2 kgf/cm2, 38--46 psi} (Vacuum hose to pressure regulator discon- nected) i INSTALL CLAPS I ACTION Go to next step Replace air cleaner element G= page F-99 Repair or replace Go to next step Go to Step 15 Go to Step 14 Check if fuel injector resistance is OK ccsf page F-119 Resistance: Approx. 12-16R - 0 If OK, check wiring between PCME and fuel injector a? page F-7 O If not OK, check fuel injector for fuel leakage page F-120 Check wiring between PCME and fuel injector ccsf page F-7 Go to next step Check for cause (Refer to "Check Point for Each Termi- nal") mzf page F-148 Check if fuel line pressure decreases when accelerating quickly O If decreases, check fuel pump maximum pressure page F-115 If OK, check fuel line and filter for clogging O If no decreases, go to next step Low pressure Check fuel line pressure while pinching fuel return hose 13 If fuel line pressure quickly increases, check pressure regulator mzf page F-118 6 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 Gartner Banana

TROUBLESHOOTING GUIDE I IESCRIPTION I Engine runs rough while decelerating and abnormal combustion occurs in exhaust system 26 TROUBLESHOOTING HINTS] 3 AirIFuel mixture too rich Air cleaner element clogged Fuel injection control malfunction (Fuel cut control) Fuel injector fuel leakage 0 Ignition timing misadjustment iTEP I INSPECTION RUNS ROUGH ON DECELERATIONIAFTERBURN ;heck if "00" is displayed on Self-Diagnosis Check- ?r with ignition switch ON page F-79 Sheck switches for correct operation with Self- Diagnosis Checker Monitor Lamp and ignition switch ON page F-95 SELECT SW A SYSTEM SELECT 1 Check for correct ignition timing at idle @= page F-76 lgnition timing: 10" 2 lo BTDC Check if fuel cut operation is OK during decelera- tion Fuel cut: Above 1,900 rpm after warm-up Yes Yes Yes - No Yes ACTION 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 03% page F-145 Specification: Battery positive voltage (Ignition switch ON) 0 If OK, replace PCME IGS page F-143 0 If not OK, check wiring between PCME and Self-Diagno- sis Checker page F-7 Go to next step Lamp not ONIOFF with specified switch Check for cause (Refer to specified check sequence) page F-96 Lamp always ON Check wiring between PCME terminal 1 D and Self-Diag- nosis Checker G+F page F-7 Go to next step Adjust page F-76 Go to next step Try known good PCME I@= page F-144 Gartner Banana