Ignition System Troubleshooting; No Spark At Spark Plug - Honda TRX500FM Service Manual

IGNITION SYSTEM
TROUBLESHOOTING
Inspect the following before diagnosing Ihe system:
- 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)
"Initial voltage" of the ignition primary coil is Ihe battery voltage with the ignition switch turned ON. (The engine is not cranked by
Ihe starter motor)
No spark at spark pl ug
iI
voltage
CKP sensor
5-4
ignition switch ON.
(Other electrical componen ts
are normal.)
;
2. An open circuit in the Black/red wire between the ignition coil and
ignition switch.
3. l oose or poor connection of the primary terminal, or an open circuil in
the primary coil.
when
the initial
voltage is njormal
with the
I
drops by 2 - 4 V while cranking voltage is over specifications reverse connections)
the engine. 2. Battery is undercharged. (Voltage drops largely when the engine is
started)
3. No voltage at the Black/red wire of the PCM/ECM (Gray) connector,
or loose or poorly connected PCM/ECM (Gray) connector
4.
Loose or poor connection, or an open circuit in the Green (ground)
wire of the PCM/ECM .
5.
Loose or poor connection, or an open circuit in the Green/yellow wire
between the ignition coil and PCM/ECM.
6.
A short circuit in the ignition primary coil.
7.
Faulty engine stop switch.
8. No voltage at the Blacklwhite wire of the PCM/ECM (Black)
connector, or loose or poorly connected PCM/ECM (Black) connector.
9.
Faulty CKP sensor. (Measure the peak voltage)
10.Faulty PCMfECM (in case when above No. 1 through 9 are normal).
Initial voltage is normal but
1. Incorrect peak voltage adaptor connections. (System is normal if
there is no peak voltage while
measured voltage is over the specifications with reverse connections)
cranking the engine.
2.
Faulty peak voltage adaptor.
3.
Faulty engine stop switch .
4.
Faulty CKP sensor. (Measure the peak voltage)
5. Faulty PCM/ECM (in case when above No. 1 and 4 are normal).
Initial voltage is normal but
1.
The mullimeter impedance is too low; below 10 MOIOCV.
peak voltage is lower than the
2.
Cranking speed is too slow. (Battery is undercharged)
standard value.
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)
r---rnilial and peak voltages are
4.
Faulty PCM/ECM (in case when above No.1 through 3 are normal).
1.
Faulty spark plug or leaking ignition coil secondary current.
normal but no spark jumps.
2. Faulty ignition coil.
Low peak voltage.
1.
The multimeter impedance is too low; below 10 MO/OCV.
2.
Cranking speed is too slow. (Battery is undercharged)
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)
t--
No peak voltage.
4.
Faulty CKP sensor (in case when above No. 1 through 3 are normal) .
1. Faulty peak voltage adaptor.
2.
Faulty CKP sensor.