Troubleshooting - Sym Joyride 125 Service Manual

5. Fuel Injection System

Troubleshooting

EFi circuit inspection
Does the warning lamp goes on for 2 seconds and
then off?
Is battery voltage over 12.5V?
The voltage difference between battery and ECU is
less than 0.2V.
1. Turn off the main switch.
2. Disconnect the ECU connector.
3. Turn on the main switch.
4. With a multi-meter to measure the voltage
between the F4 pin(+) and the H4 pin (-).
Make sure the voltage difference between
battery and ECU is less than 0.2V.
The voltage difference between battery and active
components is less than 0.2V.
1. Turn off the ignition switch.
2. Disconnect the connectors of the fuel injector,
by-pass valve, and ignition coil.
3. Measure the voltage between battery negative
side and the each connector (1).
4.
Make sure the voltage difference between
battery and those active components is less
than 0.2V.
The voltage difference between 5V-sensors is less
than 0.2V.
1. Turn off the ignition switch.
2. Disconnect the connectors of throttle valve
position sensor and intake manifold
temperature/pressure sensors.
3. Turn on the ignition switch.
4. Measure the voltage between the pins(1)(4) of
throttle valve position, and the pins of intake
manifold temperature/pressure sensors (1) (3) is
within 5V±0.2V.
The voltage difference between battery and fuel
pump is less than 0.2V.
1. Turn off the ignition switch.
2. Disconnect the fuel pump connector.
3. With the probes of multi-meter to touch the
positive & negative sides of the fuel pump.
4. Turn on the ignition switch.
5. Record the voltage difference of the fuel pump
within 3 seconds.
6. Make sure the voltage difference between
battery and fuel pump is less than 0.2V.
5-10
To this chapter contents
Switch on
OK
OK
OK
OK
OK
OK
END
1. Burnt Bulb?
2. Blown fuse?
3. Battery voltage too low?
NG
4. Poor wire contact on ECU
circuit?
5. Poor contact on the master
switch?
6. Malfunction of ECU?
NG
1. Abnormal charging circuit?
2. Battery cannot be charged?
3. Short wire circuit?
NG
1. Abnormal wire connection?
NG
1. Abnormal wire connection?
NG 1. Abnormal wire connection?
2. Malfunction of ECU?
1. Abnormal wire connection?
NG
2. Malfunction of relay?
3. Malfunction of ECU?