BOMBARDIER Johnson 90 Service Manual page 68

ENGINE CONTROL SYSTEM
COMPONENTS FOR SYSTEM CONTROL
CYLINDER TEMPERATURE SENSOR
The cylinder temperature sensor is installed on the cylinder
(top side) and used to detect the cylinder temperature.
This is a thermistor type sensor (resistance of which changas
depending on the temperatura) and inputs a signal to the
ECM as a voltage value. This input signal is used to compen­
sate the fuel injection time duration. ignition timing, etc.
This sensor is also used to detect engine overheat as the
ECM detects both the temperature and temperature change
gradient (temperature rise vs. time).
EXHAUST MANIFOLD TEMPERATURE SENSOR
The exhaust manifold temperature sensor is installed on the
exhaust manifold and used to detect the exhaust manifold
temperature. This sensor is the same type as the cylinder
temperature sensor, and inputs a signal to the ECM as a volt­
age value. This input signal is also used to detect engine
overheat.
IAT (lntake Air Temperature) SENSOR
The IAT sensor is installed on the bottom of the air silencer
and used to detect the intake air temperature. This sensor is
the same type as the cylinder temperatura sensor, and inputs
a signal to the ECM as a voltage value. This input signal is
used to compensate the fuel injection time duration.
MAP (Manifold Absolute Pressure) SENSOR
The MAP sensor is installed on the intake manifold and used
to detect the intake manifold pressure. lt also detects the
barometric pressure befare starting the engine. This sensor
inputs the intake manifold pressure to the ECM as a voltage
value. This input signal is used as the fundamental signal to
determine the fuel injection time duration, ignition timing, etc.
(kn)
Temperatura (Cº)
3-8