Isuzu C22NE Workshop Manual page 468

6E1-298 DRIVEABILITY AND EMISSIONS
IGNITION COILS
The all engines use 2 ignition coils, 1 per 2 cylinders. A two-
wire connector provides a 12-volt primary supply through the
15-amp ignition coil fuse.
IGNITION CONTROL
The ignition control (IC) spark timing is the ECM's method of
controlling the spark advance and the ignition dwell.
The IC spark advance and the ignition dwell are calculated by
the ECM using the following inputs:
• Engine speed.
• Crankshaft position (58X reference).
• Engine coolant temperature (ECT) sensor.
• Throttle position (TP) sensor.
• Vehicle speed (vehicle speed sensor).
• ECM and ignition system supply voltage.
IGNITION CONTROL ECM OUTPUT
Ignition Coil works to generate only the secondary voltage be
receiving the primary voltage from ECM.
The primary voltage is generated at the coil driver located in
the ECM. The coil driver generate the primary voltage based
on the X58 signal. In accordance with the X58 signal, ignition
coil driver determines the adequate ignition timing and also
cylinder number to ignite.
Ignition timing is determined the Coolant Temp., Intake Air
Temp., Engine Speed, Engine Load, knock Sensor Signal, etc.
ENGINE CONTROL MODULE (ECM)
The ECM is responsible for maintaining proper spark and fuel
injection timing for all driving conditions. To provide optimum
driveability and emissions, the ECM monitors the input signals
from the following components in order to calculate spark
timing:
• Engine coolant temperature (ECT) sensor.
• Intake air temperature (IAT) sensor.
• Throttle position sensor (TPS).
• Vehicle speed sensor (VSS).
• Crankshaft position (CKP) sensor.