Electronic Fuel Injection System - BOMBARDIER Johnson 90 Service Manual

ENGINE CONTROL SYSTEM
ELECTRONIC FUEL INJECTION SYSTEM
ELECTRONIC FUEL INJECTION SYSTEM
The fuel injection system used by the 90/115/140 is a speed-density, multi-point, sequential, electronic
fuel injection type. The fuel injection system is composed of the fuel line components, air intake compo­
nents, and components for system control (ECM, sensors, switches, etc.).
Fuel lnjection Control System
OUTLINE
Sensors are mounted at precise locations on the motor to monitor the current conditions of engine oper­
ation and send signals to the ECM. Based on these signals, the ECM determines the optimum fuel injec­
tion 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 BTDC 445º on exhaust stroke
constant.
ECM
Basic sensors
CvM
MAP sensor:
Fuel injection time duration
lnforms ECM of intake manifold pressure.
- -
(amount) is determinad by a
CKP sensor:
digital map designad in relation
lnforms ECM of engine speed and crankshaft angle.
-
to intake manifold pressure and
.
engine speed.
Compensating sensors
ú
Cyllnder temperature sensor:
lnforms ECM of cylinder temperatura.
IATsensor:
n
Fuel amount compensation
- . -
lnforms ECM of intake air temperatura.
,. .
~
.
MAP sensor:
-
lnforms ECM of barometric pressure at time of engine
-
:;j
Multi-point sequential timing
starting.
-
, . .
Battery voltage:
••
Constantly monitored by the ECM.
>--
l
1
Others
Signal
1 1
Signal
1 [
Signal
11
Signal
1
+ +
•
•
CMP sensor:
lnforms ECM of camshaft angle.
'--
t t t t
CTP switch:
lnforms ECM of throttle position (open/ closed).
. . _ _
Neutral switch:
!/t. !/t. !/t. !/t.
lnforms ECM of shift position (Neutral or in gear).
-
lnjector
ECM
Battery
charge
coil
ECM
CPU
141- - - Sensor/ switch
slgnal input
Battery
lnjector
(Vol~ge)
l
lnjection time
duratlon
®
terminal voltage (Time)
3-13