VESPA 946 E4 EMEA 2021 Manual page 192

Injection
N.B.
THE UNITS OF MEASUREMENT CONTAINED IN THIS CHAPTER ARE EXPRESSED IN TERMS
OF THE DECIMAL METRIC SYSTEM. TO REFER TO THE UNIT OF MEASUREMENT EXPRESSED
IN TERMS OF THE ANGLO-SAXON SYSTEM, SEE THE "CHARACTERISTICS" CHAPTER.
Precautions
Troubleshooting tips
1. An injection system failure is more likely to be due to the connections rather than to the components.
Before troubleshooting the system, carry out the following checks:
A: Electrical power supply
a. Battery voltage
b. Blown fuse
c. Relays
d. connectors
B: Frame ground
C: Fuel system
a. Faulty fuel pump
b. Dirty fuel filter
D: Ignition system
a. Faulty spark plug
b. Faulty coil
c. Faulty shielded cap
E: Intake circuit
a. Air filter dirty
b. b. Dirty by-pass circuit
c. Faulty stepper motor
F: Other
a. Wrong timing system
b. Wrong idle mixture
c. Wrong reset of the throttle valve position sensor
2. Failures in the system may be caused by loose connectors. Make sure that all connections are
properly implemented.
Check the connectors taking into consideration the following point:
A: check that the terminals are not bent.
B: check that the connectors have been properly connected.
C: check whether the failure changes if the connector is slightly vibrating.
3. Check thoroughly the entire system before replacing the control unit. If the fault is fixed even by
replacing the control unit, install the original control unit again and check if the fault occurs again.
INJEC - 192
Vespa 946 E4-E5 EMEA-USA-ASIA (2021-)