PIAGGIO MP3 400 i.e., Service Manual, Page: 205 / 394

Starting difficulties
ENGINE START-UP PROBLEMS
Possible Cause Operation
Presence of faults detected by the self diagnosis Pump relay
HV coil
Injector
revolution timing sensor
Air temperature
Coolant temperature
Start-up speed Starter motor and remote control
Battery
Ground connections
End of compression pressure End of compression pressure
Power to the spark plug Spark plug
Shielded cap
HV coil
Revolution timing sensor
Ignition advance
Fuel supply Fuel pressure (low)
Injector capacity (low)
Injector sealing (poor)
Correctness of the parameters Coolant temperature
Stepper throttle valve position intake air tempera-
ture (steps and actual opening)
Cleaning of the auxiliary air pipe and throttle valve;
air filter efficiency
Engine stops at idle
ENGINE DOES NOT HOLD IDLING/ IDLING IS UNSTABLE/ IDLING TOO LOW
Possible Cause Operation
Presence of faults detected by the self diagnosis Pump relay
HV coil
Injector
revolution timing sensor
Air temperature
Coolant temperature
Ignition efficiency Spark plug
Ignition timing
Correctness of the parameters Throttle valve position sensor
Stepper
Coolant temperature sensor
Intake air temperature sensor
Intake system cleaning Air filter
Diffuser and throttle valve
Additional air pipe and Stepper
Intake system sealing (infiltrations) Intake manifold - head
Throttle body - manifold
Intake sleeve
Filter box
Fuel feed (low pressure) Fuel pump
Pressure regulator
MP3 400 i.e.
Injection
INJEC - 9