VESPA GTV 250 i.e. 2008 Service Station Manual page 162

Injection
Possible Cause
Fuel system
Correctness of the parameters
Engine stops at idle
ENGINE DOES NOT IDLE/ IDLING IS UNSTABLE/ IDLING TOO LOW
Possible Cause
Faults detected by self-diagnosis
Ignition efficiency
Correctness of the parameters
Intake system cleaning
Intake system sealing (infiltrations)
Fuel system (low pressure)
Engine does not rev down
ENGINE DOES NOT RETURN TO IDLING SPEED/IDLING SPEED TOO HIGH
Possible Cause
Faults detected by self-diagnosis
Ignition efficiency
Correctness of the parameters
Intake system sealing (infiltrations)
Fuel system (low pressure)
INJEC - 162
Vespa GTV 250 i.e.
Operation
H.V. coil
Engine speed timing sensor
Ignition advance
Fuel pressure (low)
Injector flow (low)
Injector sealing (poor)
Coolant temperature
Intake air temperature Stepper throttle valve position (steps
and actual opening)
Cleaning of the auxiliary air pipe and throttle valve; air filter ef-
ficiency
Operation
Pump relay
H.V. coil
Injector
Engine speed timing sensor
Air temperature
Coolant temperature
Spark plug
Ignition timing
Throttle valve position sensor
Stepper
Coolant temperature sensor
Intake air temperature sensor
Air filter
Diffuser and throttle valve
Additional air pipe and Stepper
Intake manifold - head
Throttle body - manifold
Intake sleeve
Filter housing
Fuel pump
Pressure regulator
Fuel filter
Injector flow
Operation
Pump relay
H.V. coil
Injector
Engine speed timing sensor
Air temperature
Coolant temperature
Ignition timing
Throttle valve position sensor
Stepper
Coolant temperature sensor
Intake air temperature sensor
Intake manifold - head
Throttle body - manifold
Intake sleeve
Filter housing
Fuel pump
Pressure regulator
Fuel filter
Injector flow