Service manual

06-8
THROTTLE POSITION SENSOR (TPS):
TPS is used to monitor the position of the throttle and is located on the butterfly spindle so
that it can directly monitor the position of the butterfly throttle valve. The sensor is usu-
ally a potentiometer and therefore provides a variable resistance depending upon the posi-
tion of the butterfly valve and hence throttle position can be sensed by the ECU. The sensor
signal is used by the ECU as an input to its control system. The ignition timing and fuel
injection timing (and potentially other parameters) are altered depending upon the position
of the throttle, and also depending on the rate of change of the position.
THE ECU USES THE THROTTLE VALVE POSITION TO KNOW:
✰ The mode in which the engine is operating. i.e. idle, part throttle, wide-open throttle
etc.
✰ Emission controls at wide-open Throttle (WOT).
✰ Air-fuel ratio correction.
✰ Power increase correction.
✰ Fuel cutoff control.
MANIFOLD PRESSURE SENSOR (MAP):
The MAP provides instantaneous manifold pressure information to the ECU. This is neces-
sary to calculate air density and determine the engine’s air mass flow rate, which in turn is
used to calculate the appropriate fuel flow to the engine through the injector.
MANUAL BI STARTER
Located in the throttle body and operated manually through a lever on the handle bar LH.
When the lever is pulled down, a cable pulls up the spring loaded piston in the throttle
body.
Helps in providing additional air into the engine during cold start, for better idling RPM,
till the engine operating temperature is attained.
Function of Components in EMS