check engine MAZDA MX-5 1994 Workshop Manual

IGNITION SYSTEM G GND TEN I I I IGNITION TIMING 1. Check the condition of the engine (spark plugs, leaks in hoses, etc.). 2. Verify that all accessories are OFF. 3. Warm up the engine to the normal operating tempera- ture. Note When using an externally powered timing light and/or tachometer connect it to the power connector (Blue: l-pin). Warning Do not ground the power connector. terminal (Blue: l-pin); some fuses will be burned. 4. Connect a timing light and tachometer to the data link connector terminal (IG-). 5. Connect the SST and set TEST SW to "SELF TEST" or connect data link connector terminals TEN and GND with a jumper wire. 6. Check the idle speed, and set it to specification if neces- sary (Refer to section F.) ' Idle speed (rpm):800-900 (MT) 75-50 (AT) 7. Verify that the timing mark (white) on the crankshaft pulley is aligned with the indicator pin. Ignition timing: 9"-11" BTDC (at idle) 8. If the marks are not aligned, remove the ignition coil bracket and push the ignition coil aside for easy access and then loosen the crankshaft position sensor lock bolts, and turn the crankshaft position sensor to make the adjustment. 9. Tighten the crankshaft position sensor lock bolts to the specified torque. Tightening torque: 19-25 N-m (1 3-2.6 kgf~m, l4--19 ft.lbf) 10. After adjusting the ignition timing, disconnect the jumper wire or SST from the data link connector. 11. Increase the engine speed and verify that the ignition timing advances. Gartner Banana

G IGNITION SYSTEM BURNS PLUG GAP DAMAGE AND DETERIORATION DAMAGE SPARK PLUG Removal 1 Installation Caution Pulling on the wire part of the spark plug lead may i/ break it. To remove the lead, pull only on the boot. Caution To avoid breaking the spark plug be sure to fit the socket squarely over it. Tighten to the specified torque. Spark plug tightening torque: 15--22 N-m (1.5--2.3 kgf-m, 11-16 ft-lbf) Spark Test 1. Disconnect the high-tension lead from the spark plug. 2. Connect a new spark plug to the high-tension lead. 3. Hold with insulated pliers approx. 5-10mm (0.20-4.39 in) from a ground. 4. Crank the engine and verify that a strong blue spark is visible. . -.d' Note If a timing light is used to check for spark, some lights do not light at Nos.:! and 4 cylinders even if the igni- tion system is normal. Inspection Check the following and replace the spark plugs as neces- sary. 1. Damaged insulation. 2. Worn electrodes. 3. Carbon deposits. If cleaning is necessary, use a plug cleaner or a wire brush. Wipe upper insulator. 4. Damaged gasket. Plug gap: 1 .O-1 .l mm (0.040-0.043 in) Gartner Banana

K TROUBLESHOOTING TROUBLESHOOTING GENERAL NOTES A problem with the EC-AT may be caused by the engine, the EC-AT powertrain, the hydraulic control LJ system, or the electronic control system. When troubleshooting, therefore, begin from these points, which can be inspected quickly and easily. The recommended troubleshooting sequence is described below. WHEEL CHOCK 63 TEMPERATURE w-7u'C (1461WF) Step 1 : On-board Diagnosis System Inspection Check for diagnostic trouble code(s) memorized in the powertrain control module (Transmission) with the Self- Diagnosis Checker. (Refer to page K-11 .) Note You can also check the flashing sequence of the hold indicator light for diagnostic trouble code(s). (Refer to page K-1 1 .) Step 2: Mechanical System Test Check the engine stall speed, time lag, and line pres- sure. (Refer to page K-22.) Step 3: Road Test Check the shift point, shift schedule, and shift shock. (Refer to page K-29.) Gartner Banana

TROUBLESHOOTING If the 3 steps on page K-8 are followed, the cause of the problem should be located. Another guide to faster location of the causes of problems, the QUICK DIAGNOSIS CHART, is on page K-1 0. b In this chart, numbers are used to indicate the components that may be the cause of 22 possible prob- lems. It is necessary to check only those components indicated by numbers during each step of the trouble- shooting process to locate the cause of the problem quickly. QUICK DIAGNOSIS CHART The QUICK DIAGNOSIS CHART shows different .problems and the relationship of components that might be the cause. 1. Components indicated in the "Adjustment" row indicate the possibility that the problem may result from an incorrect adjustment. Check the adjustment of each component, and readjust if necessary. 2. Components indicated in the "Self-DiagnosisWrow are diagnosed by the Powertrain control module (Transmission) self-diagnostic function. 3. Input and output signals of the Powertrain control module (Transmission) for components indicated in the "Tester" row can be easily checked with the Engine signal Monitor. 4. Components indicated in the "Mechanical System Test" row can be checked for malfunction by the re- sults of oil pressure test. 5. Components indicated in the "Road Test" row can be checked for malfunction by the results of the road test. 6. The numbers in the chart indicate the order of inspection for detecting malfunctions. 7. Circled numbers indicate that the transmission must be removed from the vehicle. 8. The checking, adjusting, repair, and replacement procedures for components are described in the page(s) shown in the "Reference page" row. Gartner Banana

ON-BOARD DIAGNOSIS SYSTEM K :TIC TROUBLE CODE No.55 VEHICLE SPEED PULSE GENERATOR ACTION Repair or replace connector INSPECTION control module (transmission) connector or terminal? I (+) term. 1 (-) term. I Voltage (v)( Condition I Are there any poor connections at vehicle speed pulse generator and powertrain No ' Go to next step Connect a circuit tester to terminal as shown Is input voltage of vehicle speed pulse generator at powertrain control module (transmission) OK? page K45 Engine Yes Engine I o ( stopped ( Yes Disconnect 20-pin powertrain control module (transmission) connector Is resistance between terminal 2J and ter- minal 2L OK? Go to step 5 I No I Go to next step Yes Go to step 5 Resistance: 200--400a Disconnect vehicle speed pulse genera- tor connector Is resistance between terminal E and ter- minal F OK? page K41 Resistance: 200--400n Disconnect the negative battery cable for at least 20 seconds and depress the brake mdal Sonnect the battery cable and recheck for jiagnostic trouble code Is diagnostic trouble code displayed? page K-21 45UOKX-019 Yes No Yes No Check wiring and connectors form powertrain control module (transmission) vehicle speed pules generator If OK, go to next step If not OK, repair wiring and/or connector Replace pulse generator Replace powertrain control module (transmission) us page K-45 Intermittent poor connection Check for cause Gartner Banana

K MECHANICAL SYSTEM TEST MECHANICAL SYSTEM TEST PREPARATION SST STALL TEST 49 0378 400A Gauge set, oil pressure 49 801 9 901 Gauge, oil pressure For oil pressure test For oil pressure test This test is performed to determine if there is slippage of the friction elements or malfunction of the hy- draulic components. Preparation 1. Check the engine coolant, engine oil, and ATF levels before testing. 2. Warm the engine thoroughly to raise the ATF temperature to operating level (50--80°C, 122-176°F). 3. Engage the parking brake and use wheel chocks at the front and rear of the wheels. ENGAGE PARKING BRAKE WARM UP ENGINE COOLANT LEVEL ENGINE OIL LEVEL TEMPERATURE 60-70°C (1 40-1 58°F) ATF LEVEL Gartner Banana

MECHANICAL SYSTEM TEST K Procedure ENGAGE PARKING BRAKE IDLE SPEED 1. Connect a tachometer to the engine. 2. Start the engine and check the idle speed in P range. (Refer to section F.) Idle speed: 750-450 rpm 3. Shift the selector lever to R range. Caution If the accelerator pedal is pressed for longer than 5 seconds while the brake pedal is pressed, the transmission could be damaged. Therefore, do steps 4 and 5 within 5 seconds of each oth- er. 4. Firmly depress the foot brake with the left foot, and gently depress the accelerator pedal with the right. 5. When the engine speed no longer increases, quickly read the engine speed and release the accelerator. 6. Shift the selector to N and let the engine idle for 1 minute or more to cool the ATF. 7. Perform the stall test for the following ranges in the same manner. (1 ) D range u (2) S range (3) L range Engine stall speed: 1,90&2,lOO rpm Gartner Banana

MECHANICAL SYSTEM TEST TIME LAG TEST If the selector lever is shifted while the engine is idling, there will be a certain time lapse, or time lag, before shock is felt. This step checks this time lag for checking condition of the 1-2, N-R/2-3 and N-D L/ accumulators, front, rear and one-way clutches, 2nd brake band, and low and reverse brake. Preparation Perform the preparation procedure shown in the STALL TEST. (Refer to page K-22.) Procedure IDLE SPEED 1. Start the engine and check the idle speed in P range. (Refer to section F.) u Idle speed: 750--850 rpm 2. Shift from N range to D range. 3. Use a stopwatch to measure the time it takes from shifting until shock is felt. 4. Shift the selector to N and let the engine idle for 1 minute or more to cool the ATF. 5. Do the time lag test for the following shifts in the same manner. Make three measurements for each test and average the results. (1) N 4 D range (Normal mode) (2) N -+ D range (Hold mode) (3) N -+ R range .......................................... Specified time lag: N -t D range 0.5-46 second ..................... N -+ R range ... .............. 0.75-0.85 second Evaluation of Time Lag Test - I Condition N -c D (Hold) shifting More than specification Less than specification More than specification Less than specification N -+ R shifting I More than specification Less than specification Rear clutch slipping Excessive line pressure - lnsufficient line pressure Rear clutch slipping 2nd brake band slipping - 1-2 accumulator not operating properly Excessive line pressure lnsufficient line pressure Low and reverse brake slipping Front clutch slipping N-R/2-3 accumulator not operating properly Excessive line pressure K-25 Gartner Banana

K MECHANICAL SYSTEM TEST LINE PRESSURE TEST This test measures line pressures for checking the hydraulic components and inspecting for oil leakage. Preparation d 1. Perform the preparation procedure shown in the STALL TEST. (Refer to page K-22.) 2. Connect a tachometer to the engine. Warning Removing the square-head plug when the ATF is hot is dangerous. Hot ATF can come out of the opening and badly burn. Before removing the square-head plug, allow the ATF to cool. 3. Connect the SST to the line pressure inspection hole(s). Procedure 1. Start the engine and check the idle speed in P range. (Refer to section F.) Idle speed: 750--850 rpm * 2. Shift the selector lever to D range and read the line pressure at idle. Caution If the accelerator pedal is pressed for longer than 5 seconds while the brake pedal is pressed, the transmission could be damaged. Therefore, do steps 3 and 4 within 5 seconds of each oth- er. 3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with the right foot. 4. Read the line pressure as soon as the engine speed becomes constant, then release the accelerator .- pedal. 5. Shift the selector to N and let the engine idle for 1 minute or more to cool the ATF. 6. Read the line pressure at idle and at the engine stall speed for each range in the same manner. Gartner Banana

ROAD TEST K ROAD TEST A road test is necessary to inspect for problems in the different gear ranges. If a range or function tar- b geted by the road test is found to have any problem, refer to the ELECTRONIC SYSTEM COMPONENT segment or the TRANSMISSION, OIL COOLER, DRIVE PLATE, and SHIFT MECHANISM segments of this section. Do the road test only when the ATF is 50-80°C (1 22-1 76°F). D-RANGE TEST Shift Point, Shift Pattern, and Shift Shock 1. Shift the selector lever to D range and select the Normal mode. 2. Accelerate the vehicle with half-and wide open throttle opening. 3. Verify that 1-2, 2-3, and 3-4 upshifts, downshifts, and lockup are obtained. The shift points must be as shown in the D range (Normal) shift diagram. Note There is fourth gear is any of the following conditions. A The cruise control is operating, and there is an 8kmIh (5 mph} difference between the preset cruise speed and the vehicle speed. B The SET or RESUME switch is ON. There is no lockup when water temperature is below 50°C (1 22°F) or in the throttle valve closed posi- tion. 4. Check the upshifts for shift shock or slippage in the same manner. 5. While driving in overdrive, shift the selector lever to S range and verify that 4-3 downshift immediately occurs, then decelerate and verify that engine braking effect is felt in only third gear and 2nd gears. D-range (Normal) shift diagram p'yJ ..,,*sw.. LOCKUP AVAILABLE WHEN ACCELERATING AND CRUSING LOCKUP AVAILABLE WHEN COASTING 0 20 (1 2) 40 (25) 60 (37) 80 {50) 100 (63) 1 20 (75) 140 (87) 1 60 (99) VEHICLE SPEED kmlh {mph) Gartner Banana