Electronic Fuel Injection System; Fuel Injection Control System - Suzuki DF150 Service Manual

ELECTRONIC FUEL INJECTION SYSTEM

The fuel injection system used by the DF150/DF175 is a speed-density, multi-point, sequential, electronic
fuel injection type.
The fuel injection system is composed of the fuel line components, air intake components, and components
for system control (ECM, sensors, switches, etc.).

FUEL INJECTION CONTROL SYSTEM

OUTLINE
Sensors are mounted at precise locations on the motor to monitor the current conditions of engine operation
and send signals to the ECM. Based on these signals, the ECM determines the optimum fuel injection time
duration (fuel amount), fuel injection timing (multi-point sequential timing) and controls the injector operating
signals accordingly.
Fuel injection start timing is set at a constant of ATDC 275° on the exhaust stroke.
Basic sensors
MAP sensor:
Informs ECM of intake manifold pressure.
CKP sensor:
Informs ECM of engine speed and crankshaft angle.
Compensating sensors
Cylinder temperature sensor:
Informs ECM of cylinder temperature.
Exhaust manifold temperature sensor:
Informs ECM of exhaust manifold temperature.
IAT sensor:
Informs ECM of intake air temperature.
TPS (Throttle position sensor):
Informs ECM of throttle opening angle.
MAP sensor:
Informs ECM of barometric pressure at time of engine start.
Battery voltage:
Constantly monitored by the ECM.
Others
CMP sensor:
Informs ECM of camshaft angle.
Shift position sensor:
Informs ECM of shift position (neutral or in-gear).
Battery
charge
coil
Rectifier &
regulator
60A fuse
Battery
ECM
main
relay
A
30A fuse
15A fuse
Ignition
switch
Fuel injection time duration
(amount) is determined by
a digital map designed in
relation to intake manifold
pressure
speed.
Fuel amount compensation
Multi-point sequential timing
Signal
ECM
CPU
A A A
Injector
ENGINE CONTROL SYSTEM
ECM
and engine
Signal Signal Signal
Injector
Sensor/switch
signal input
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