Testing Ignition System; Ignition Troubleshooting - Suzuki DF 25 Service Manual

3-6 ENGINE CONTROL

TESTING IGNITION SYSTEM

IGNITION TROUBLESHOOTING

Perform the following ignition system tests when engine is hard to start to determine if the cause is in the
ignition or another system.
START
Check spark condition.
No or weak sparks
Check if the spark plug is in good condi-
tion. (See page 2-8)
OK
Disconnect the engine stop switch wire
(Green or Blue / Red).
No or weak sparks
Check the ignition coil resistance.
(See page 3-7)
[Primary: 0.17 – 0.23 Ω,
Secondary: 3.3 – 5.0 kΩ]
OK
Check spark plug cap for any evidence of
high-tension leak.
OK
Check the spark plug cap resistance.
(See page 3-8)
[Cap resistance: 4 – 6 kΩ]
OK
Check the Power source coil resistance.
(See page 3-8)
[Coil resistance: 10.1 – 15.1 Ω]
OK
Check the CKP sensor resistance.
(See page 3-9)
[Sensor resistance: 148 – 222 Ω]
OK
Sparks
Check ignition timing by using tim-
ing light.
Not good
Sparks
Out of spec.
Not good
Out of spec.
Out of spec.
Out of spec.
The cause will not be in ignition system.
OK
Replace the spark plug with new one.
Check and/or replace
• the engine stop switch. (See page 3-11)
• ignition switch. (See page 4-10)
Replace the ignition coil.
Replace the spark plug cap.
Replace the spark plug cap.
Replace the coil.
Replace the CKP sensor(s).
Replace CDI unit.
Not good