IGNITION SYSTEM
SERVICE INFORMATION
TROUBLESHOOTING
IGNITION SYSTEM INSPECTION
IGNITION COIL
IGNITION TIMING
SERVICE INFORMATION - GENERAL
Some electrical components may be damaged if terminals or connectors are connected or disconnected while the ignition switch is ON and current is present. When servicing the ignition system, always follow the steps in the troubleshooting on page. The ignition timing cannot be adjusted since the ignition control module (ICM) is factory preset. The ICM may be damaged if dropped. Also, if the connector is disconnected when current is flowing, the excessive voltage may damage the ICM. Always turn off the ignition switch before servicing. A faulty ignition system is often related to poor connections. Check those connections before proceeding. Use a spark plug of the correct heat range. Using spark plug with an incorrect heat range can damage the engine. For ignition switch and engine stop switch inspection. For ignition pulse generator (alternator stator) removal/installation.
SPECIFICATIONS
- Spark plug Standard - DPR7EA-9 (NGK) X22EPR-U9 (DENSO)
- For cold climate (below 5°C/41°F) - DPR6EA-9 (NGK) X20EPR-U9 (DENSO)
- Spark plug gap - 0.8 0.9 mm(0.03 0.04 in)
- Ignition coil primary peak voltage - 100 V minimum
- Ignition pulse generator peak voltage - 0.7 V minimum
- Ignition timing (‘‘F’’ mark) - 11° BTDC at idle
TORQUE:Timing hole cap - 10 N·m (1.0 kgf·m , 7 lbf·ft)
IGNITION SYSTEM - TROUBLESHOOTING
Inspect the following before diagnosing the system:
- Faulty spark plug
- Loose spark plug cap or spark plug wire connections
- Water got into the spark plug cap (Leaking the ignition coil secondary voltage)
Ignition coil primary voltage: Low peak voltage.
Incorrect peak voltage adaptor connections. (System is normal if measured voltage is over the specifications with reverse connections.)
- The multimeter impedance is too low; below 10M / DCV.
- Cranking speed is too low. (Battery is undercharged.)
- The sampling timing of the tester and measured pulse were not synchronized. (System is normal if measured voltage is over the standard voltage at least once.)
- Poorly connected connectors or an open circuit in ignition system.
- Faulty gear position switch.
- An open circuit or loose connection in No. 6 related circuit (light green/red wire).
- Faulty ignition coil.
- Faulty ignition control module (ICM). (when above No. 1 through 8 are normal.)
No peak voltage:
- Incorrect peak voltage adaptor connections. (System is normal if measured voltage is over the specifications with reverse connections.)
- Battery is undercharged. (Voltage drops largely when the engine is started.)
- Faulty ignition switch or engine stop switch.
- Loose or poorly connected ICM connector.
- No voltage at the black/white wire of the ICM.
- Open circuit or poor connection in ground (green) wire of the ICM.
- Faulty gear position switch.
- An open circuit or loose connection in No. 7 related circuit (light green/red wire).
- Faulty peak voltage adaptor.
- Faulty ignition pulse generator. (Measure peak voltage.)
- Faulty ICM. (when above No. 1 through 10 are normal.)
Peak voltage is normal, but no spark jumps at plug:
- Faulty spark plug or leaking ignition coil secondary current ampere.
- Faulty ignition coil.
Ignition pulse generator: Low peak voltage
- The multimeter impedance is too low; 10M /DCV.
- Cranking speed is too slow. (Battery is undercharged.)
- The sampling timing of the tester and measured pulse were not synchronized. (System is normal if measured voltage is over the standard voltage at least once.)
- Faulty ignition pulse generator. (when above No. 1 through 3 are normal).
No peak voltage:
- Faulty peak voltage adaptor.
- Faulty ignition pulse generator.
If the result of the troubleshooting was likely to malfunction the ‘‘ICM’’, check as follows. Disconnect the sub-ICM connectors and connect the main harness side 8P (gray) connector to the ICM and perform the spark test. If the plug is no spark, faulty ICM. If the plug is sparks, faulty sub-ICM.
IGNITION SYSTEM INSPECTION
If not spark jumps at the plug, check all connections for loose or poor contact before measuring each peak voltage. Use recommended digital multimeter or a commercially available digital multimeter (impedance 10 M /DCV minimum). The display value differs depending internal impedance of the multimeter. Connect the peak voltage adaptor to the digital multimeter, or use the peak voltage tester.
IGNITION PRIMARY PEAK VOLTAGE
Check all system connections before this inspection. Poor connected connectors can cause incorrect readings. Check the cylinder compression and check that the spark plug is installed correctly in the cylinder. Disconnect the spark plug cap from the spark plug. Connect known good spark plug to the spark plug cap and ground the spark plug to the cylinder head as done in a spark test. With the connector connected, connect the peak voltage tester or adaptor probes to the ignition coil primary terminal and body ground.
CONNECTION: Black/yellow (-)-Body ground (+)
Turn the ignition switch ON. Crank the engine with the starter motor and read the ignition coil primary voltage.
PEAK VOLTAGE: 100 V minimum
If the peak voltage is lower than the standard value, follow the checks described in the troubleshooting in your service manual.
IGNITION PULSE GENERATOR PEAK VOLTAGE
Check that the cylinder compression is normal and the spark plug is installed correctly in the cylinder head. Disconnect the ignition control module (ICM) 8P (gray) connector. Connect the peak voltage tester or adaptor probes to the connector terminals of the wire harness side.
CONNECTION: Blue/yellow (+) Green/white (-)
Turn the ignition switch ON. Crank the engine with the starter motor and read the peak voltage.
PEAK VOLTAGE: 0.7 V minimum
If the voltage measured at ICM connector is abnormal, measure the peak voltage at the alternator connector. Disconnect the alternator 5P (white) connector and connect the peak voltage tester or adaptor probes to the Blue/yellow wire terminal of the alternator side connector and ground. In the same manner as at the ICM connector, measure the peak voltage and compare it to the voltage measured at the ICM connector.
If the peak voltage measured at the ICM connector is abnormal and the one measured at the alternator connector is normal, the Blue/yellow wire has an open or short circuit, or loose connections. If both peak voltages are abnormal, follow the checks described in the troubleshooting in your service manaul and see your service manual for stator/ignition pulse generator assembly replacement.
IGNITION COIL - REPLACEMENT
Remove the left side cover. Release the spark plug wire fromthe clip. Remove the spark plug cap from the plug. Disconnect the connectors and remove the ignition coil from the stay of the frame. Install a new ignition coil in the reverse order of removal.
IGNITION TIMING
Remove the recoil starter cover. Start the engine and warm it up operating temperature. Stop the engine and remove the timing hole cap. Connect the timing light and tachometer. Start the engine, let it idle (1,400 rpm) and check the ignition timing. The ignition timing is correct if the F mark on the flywheel aligns with the index mark on the rear crankcase cover at idle. Increase the engine speed and make sure the F mark begins to move. Coat a new O-ring with engine oil and install it onto the timing hole cap. Install the timing hole cap and tighten it.
TORQUE: 10 N·m (1.0 kgf·m , 7 lbf·ft)
Install the recoil starter cover.
FUSE BOX - (FUSE 15A/30A AND DIODE)
STARTER RELAY SWITCH
GEAR POSITION SWITCH
STARTER MOTOR
IGNITION SWITCH
STARTER SWITCH
BATTERY