Troubleshooting Hints - VESPA GTS 250 I.E. Workshop Manual

Injection
14. Before reconnecting the quick couplers of the power supply system, check that the terminals are
perfectly clean.
1 A fault in the MIU system could most likely be due to the connections and not the components.
Before troubleshooting the MIU system, carry out the following checks:
A: Electrical power supply
a. Battery voltage
b. Blown fuse
c. Remote controls
d. Connectors
B: Chassis earthing
C: Fuel supply
a. Broken fuel pump
b. Dirty fuel filter
D: Ignition system
a. Faulty spark plug
b. Broken coil
c. Broken shielded cap
E: Intake circuit
a. Dirty air filter
b. Dirty by-pass circuit
c. Faulty Stepper motor
F: Other
a. Incorrect distribution timing
b. Wrong idle mixture
c.Incorrect reset of the throttle valve position sensor
2 MIU system faults may be caused by loose connectors. Make sure that all connections have been
correctly made.
Check the connections as follows:
A check that the terminals are not bent.
B check that the connectors have been properly connected.
C see whether the malfunction can be fixed by shaking the connector slightly.
3 Check the entire system before replacing the MIUIf the fault is fixed by replacing the MIU control unit,
install the original control unit again and check if the fault occurs again.
4 When troubleshooting use a multimeter with an internal resistance over 10 Ohm /V. Instruments that
are not suitable might damage the MIU control unit. Instruments must be used with definitions over 0.1V
and 0.5 W , the precision must be greater than 2%.
INJEC - 6

Troubleshooting hints

Vespa GTS 250 I.E.