VESPA GTV 250 i.e. 2008 Service Station Manual page 163

Vespa GTV 250 i.e.
Exhaust backfires in deceleration
EXHAUST BACKFIRING WHEN DECELERATING
Possible Cause
Faults detected by self-diagnosis
Correctness of the parameters
Intake system sealing (infiltrations)
Fuel system (low pressure)
Exhaust system sealing (infiltrations)
Engine revs irregularly
ENGINE IRREGULAR PERFORMANCE WITH VALVE SLIGHTLY OPEN
Possible Cause
Intake system cleaning
Intake system sealing
Ignition system
Parameter reliability
TPS reset successful
Faults detected by self-diagnosis
Poor performance at full throttle
POOR ENGINE PERFORMANCE AT FULL POWER/ ENGINE IRREGULAR PERFORM-
Possible Cause
Faults detected by self-diagnosis
ANCE ON PICK-UP
Operation
Pump relay
H.V. coil
Injector
Engine speed timing sensor
Air temperature
Coolant temperature
Lambda probe
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
Manifold - head
Manifold - silencer
silencer welding
Operation
Air filter
Diffuser and throttle valve
Additional air pipe and Stepper
Intake sleeve
Filter housing
Spark plug wear check
Throttle valve position signal
Coolant temperature indicator
Intake air temperature signal
Ignition advance
TPS reset successful
Pump relay
H.V. coil
Injector
Engine speed timing sensor
Air temperature
Coolant temperature
Lambda probe
Operation
Pump relay
H.V. coil
Injector
Engine speed timing sensor
Injection
INJEC - 163