- Faulty spark plug
- Loose spark plug cap or spark plug wire connection
- Water got into the spark plug cap (leaking the ignition coil secondary voltage)
If there is no spark at either cylinder, temporarily exchange the ignition coil with a known-good one and perform the spark test. If there is a spark, the exchanged ignition coil is faulty.
"Initial voltage" of the ignition primary coil is the battery voltage with the ignition switch turned to "ON" and the engine stop switch turned to "
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No spark at spark plugs
Unusual condition | Probable cause (check in numerical order) | |
Ignition coil primary voltage | No initial voltage with ignition and engine stop switches on. (other electrical components are normal) | 1. Faulty engine stop switch. 2. An open circuit in Black/white wire between the ignition coil and engine stop switch. 3. Loose primary terminal or an open circuit in primary coil. 4. Faulty ECM (in case when the initial voltage is normal while disconnecting ECM connector). |
Initial voltage is normal, but it drops down to 2-4 V while cranking the engine. | 1. Incorrect peak voltage adapter connections. 2. Undercharged battery. 3. No voltage between the Black/white (+) and body ground (-) at the ECM multi-connector or loosen ECM connection. 4. An open circuit or loose connection in Green wire. 5. An open circuit or loose connection in Blue/yellow and Yellow/blue wire between the ignition coils and ECM. 6. Short circuit in ignition primary coil. 7. Faulty side stand switch. 8. An open circuit or loose connection in No.7 related circuit wires (Green/white and Green wires). 9. Faulty ignition pulse generator (measure the peak voltage). 10. Faulty ECM (in case when above No. 1-9 are normal). | |
Initial voltage is normal, but no peak voltage while cranking the engine. | 1. Faulty peak voltage adapter connections. 2. Faulty peak voltage adapter. 3. Faulty ECM (in case when above No.1, 2 are normal). | |
Initial voltage is normal, but peak voltage is lower than standard value. | 1. The multimeter impedance is too low; below 10 MΩ/DCV. 2. Cranking speed is too low (battery under-charged). 3. 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). 4. Faulty ECM (in case when above No. 1-3 are normal). | |
Initial and peak voltage are normal, but does not spark. | 1. Faulty spark plug or leaking ignition coil secondary current ampere. 2. Faulty ignition coil. | |
Ignition pulse generator | Peak voltage is lower than standard value. | 1. The multimeter impedance is too low; below 10 MΩ/DCV. 2. Cranking speed is too low (battery under charged). 3. 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). 4. Faulty ECM (in case when above No. 1-3 are normal). |
No peak voltage. | 1. Faulty peak voltage adapter. 2.Faulty ignition pulse generator. |