Infiniti QX56 (Z62). Manual - part 516
EC-42
< SYSTEM DESCRIPTION >
[VK56VD]
SYSTEM
ELECTRIC IGNITION SYSTEM : System Diagram
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ELECTRIC IGNITION SYSTEM : System Description
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INPUT/OUTPUT SIGNAL CHART
*1: ECM determines the start signal status by the signals of engine speed and battery voltage.
*2: This signal is sent to the ECM via the CAN communication line.
SYSTEM DESCRIPTION
Ignition order: 1 - 8 - 7 - 3 - 6 - 5 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injection pulse width and camshaft position sensor signal. Comput-
ing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised by the ECM according to the other data stored in
the ECM.
• At starting
• During warm-up
• At idle
• At low battery voltage
• During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
JPBIA3271GB
Sensor
Input signal to ECM
ECM function
Actuator
Crankshaft position sensor
Engine speed*
1
Piston position
Ignition timing
control
Ignition coil
(with power transistor)
Camshaft position sensor
Mass air flow sensor
Amount of intake air
Engine coolant temperature sensor
Engine coolant temperature
Throttle position sensor
Throttle position
Accelerator pedal position sensor
Accelerator pedal position
TCM
Gear position
Battery
Battery voltage*
1
Knock sensor
Engine knocking condition
Combination meter
Vehicle speed*
2