1994 MAZDA MX-5 air filter

TROUBLESHOOTING GUIDE 7 CRANKS NORMALLY BUT WILL NOT START (PARTIAL COMBUSTION) -AFTER WARM-UP I ~ngine starts normally when cold TROUBLESHOOTING HINTS] D AirIFuel mixture too rich O Vapor lock Fuel pressure not held in fuel line after engine stops High RVP (winter) fuel used in warm weather 'ESCRIPTIoN Fuel injection control malfunction (Correction for coolant temperature) Fuel injector fuel leakage I INSPECTION Engine cranks at normal speed but shows partial combustion and will not continue to run after running and hol soaked Battery in normal condition :heck if "00" is displayed on Self-Diagnosis Checker with ignition switch ON @S page F-79 :heck if PCME terminal voltages are OK :2D and 20) page F-136 sonnect data link connector terminals F/P and GND ~ith jumper wire and check for correct fuel line pres- sure with ignition switch ON page F-110 Fuel Line pressure: 26-14 kPa {2.7-3.2 kgflcm2, 38-46 psi) GND F~P INSTALL CLAPS ' Yes No - 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 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 page F-7 Go to next step Check for cause (Refer to "Check Point for Each Terminal") page F-148 Go to next step Low pressure Check fuel line pressure while pinching fuel return hose Q If fuel line pressure quickly increases, check pressure regulator page F-118 0 If fuel line pressure gradually increases, check fuel line and filter for clogging If not clogged, check fuel pump maximum pressure page F-115 - High pressure Check if fuel return hose is clogged or restricted a If OK, replace pressure regulator page F-119 6 If not OK, repair or replace Gartner Banana

TROUBLESHOOTING GUIDE INSPECTION ACTION ;heck if PCME terminal voltages are OK 2M, 20 and 20) usf page F-146 Yes - No Go to next step Check for cause (Refer to "Check Point for Each Terrni- nal") G+F page F-139 >heck if throttle linkage is correctly installed and )perates freely Yes Go to next step Correct, clean, or replace as required any binding or dam- aged linkage and adjust cable deflection at throttle body * page F-101 No - Yes >heck for correct intake manifold vacuum at idle lacuum: More than 450 mmHg (17.7 inHg} VACUUM GAUGE / - - Go to next step Check for air leakage of intake air system components G+F page F-110 >heck if air cleaner element is clean page F-76 Yes Go to next step Replace air cleaner element * page F-99 >heck for correct ignition timing at idle usf page F-76 Yes Check if ignition timing advances when accelerating 0 If advances, go to next step e If no advance, replace PCME page F-143 gnition timing: 10" 2 lo BTDC No - Yes Adjust usf page F-76 >heck for correct fuel line pressure at idle page F-110 Check if fuel line pressure decreases when accelerating quickly %el line pressure: 265-314 kPa {2.7-3.2 kgf/cm2, 38-46 psi) (Vacuum hose to pressure regulator discon- nected) If decreases, check fuel pump maximum pressure page F-115 o If OK, check fuel line and filter for clogging Low pressure Check fuel line pressure while pinching fuel return hose 9 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 Paae F-115 High pressure Check if fuel return line is clogged INSTALL CLAPS o If OK, replace pressure regulator page F-119 o If not OK, replace Gartner Banana

TROUBLESHOOTING GUIDE ACTION Go to next step INSPECTION :heck if throttle linkage is correctly installed and 3perates freely - Yes - No - Yes - No - Yes - No Correct, clean, or replace as required any binding or dam- aged linkage and adjust cable deflection at throttle body @a page F-103 Go to next step :heck if air duct and air hoses are correctly nstalled page F-99 Repair ~8 page F-99 Go to next step ;heck for correct intake manifold vacuum at idle Vacuum: More than 450 mmHg (17.7 inHg) VACUUM GAUGE Check for air leakage of intake air system components page F-100 :heck if air cleaner element is clean ttzr page F-76 Yes - No Go to next step Replace air cleaner element @a page F-99 >heck for correct ignition timing at idle page F-76 Yes - No Check if ignition timing advances when accelerating Q If advances, go to next step Q If no advance, replace PCME page F-143 Adjust page F-76 gnition timing: 10" a lo BTDC ;heck for correct fuel line pressure at idle page F-110 Yes - No - Yes Check if fuel line pressure decreases when accelerating quickly %el line pressure: 265-314 kPa I2.7-3.2 kgf/cm2, 38-46 psi] (Vacuum hose to pressure regulator discon- a If decreases, check fuel line and filter for clogging 0 If no decrease, go to next step Low pressure Check fuel line pressure while pinching fuel return hose If fuel line pressure quickly increases, check pressure regulator @a 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 INSTALL CLAPS ;heck for EGR system malfunction page F-124 Repair or replace Go to next step Repair or replace t@~ page F-128 ;heck if exhaust system is restricted page F-128 Yes Go to next step Try known good PCME and check if condition im- )roves page F-144 Gartner Banana

F TROUBLESHOOTING GUIDE INSPECTION ACTION Check if throttle linkage is correctly installed and operates freely Yes Go to next step Correct, clean, or replace as required any binding or dam- aged linkage and adjust cable deflection at throttle body r@ page F-103 Check for correct intake manifold vacuum at idle Vacuum: More than 450 mmHg I17.7 inHg) VACUUM GAUGE / Yes Go to next step No - Yes Check for air leakage of intake air system components r@ page F-100 Go to next step Check if air cleaner element is clean page F-76 Replace air cleaner element page F-99 Check for correct ignition timing at idle page F-76 Yes - No Check if ignition timing advances when accelerating .I, If advances, go to next step o If no advance, replace PCME page F-143 Adjust r@ page M6 Ignition timing: 10" -r- lo BTDC Check for correct fuel line pressure at idle page F-110 Yes Check if fuel line pressure decreases when accelerating quickly Fuel line pressure: 265-314 kPa (2.7-3.2 kgf/cm2, 38-46 psi) (Vacuum hose to pressure regulator discon- nected) o If decreases, check fuel line and filter for clogging 0 If no decrease, go to next step No - Yes Low pressure Check fuel line pressure while pinching fuel return hose 0 If fuel line pressure quickly increases, check pressure regulator page F-113 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 INSTALL CLAPS Repair or replace Check for EGR system malfunction page F-124 No - Yes - No Go to next step - -- Check if exhaust system is restricted page F-128 -- - Repair or replace So to next step Try known good PCME and check if condition im- 3roves page F-144 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 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

ENGINE TUNE-UP - TIMING LIGHT - 45UOFX422 GND Irnr Air Cleaner Element Inspection 1. Check the air cleaner element for excessive dirt and for oil and damage. Caution Cleaning the element with compressed air will re- duce the element's ability to filter the air. Don't use compressed air to clean the element. 2. Replace the element if necessary. ADJUSTMENT Preparation 1. Warm up the engine to normal operating temperature. 2. Turn all electric loads OFF. Headlight switch Blower switch Rear window defroster switch 3. Connect the SST to the data link connector. 4. Connect a timing light to the engine. 5. Connect a tachometer to the data link connector terminal IG- as shown. Ignition Timing 1. Perform Preparation. (Refer to above.) 2. Verify that the idle speed is within the specification; if not, adjust it. Idle speed 4 (Neutral): 800-900 (850 + 50) rpm [MT] (P range): 750-850 (800 & 50) rpm [AT] 3. Set switch A to position 1. 4. Set test switch to SELF TEST. 5. If the SST is not used, connect a jumper wire between the TEN terminal and the GND terminal of the data link connector. 6. Verify that the idle speed is within the specification. ldle speed (Ground the terminal TEN): 650-975 rpm 7. Verify that the timing mark (white) on the crankshaft pulley and the mark on the timing belt cover are aligned. lgnition timing: BTDC 9"-11" (10" & lo) Gartner Banana

PRESSURE REGULATOR CONTROL SYSTEM F PRESSURE REGULATOR / f PRC SOLENOID VALVE AIR FILTER U PRC SOLENOID VALVE lnspection (On-vehicle) 1. Start the engine and run it at idle. 2. Disconnect the vacuum hose from the pressure regula- tor. Verify that vacuum is felt. 3. Ground the PRC solenoid valve terminal B with a jumper wire. Verify that no vacuum is felt. 4. If vacuum exists, check the PRC solenoid valve. Inspection 1. Disconnect the vacuum hose from the PRC solenoid valve and vacuum pipe. 2. Blow through the PRC solenoid valve from port A. 3. Verify that air flows from port B. 4. Disconnect the PRC solenoid valve connector. 5. Connect battery positive voltage and a ground to the ter- minals of the PRC solenoid valve. 6. Blow through the PRC solenoid valve from the port A. 7. Verify that air flows from the valve air filter. 8. If not as specified, replace the PRC solenoid valve. Gartner Banana