2008 MITSUBISHI LANCER EVOLUTION X engine coolant

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME
MULTIPORT FUEL SYSTEM (MFI)13A-37
2. Spark-advance control and current carrying
time control
.
[During start]
ECM initiates ignition at fixed ignition timing (5° BTDC) syn-
chronized with the crankshaft position sensor signal.
.
[During normal operation]
After determining the basic spark-advance based on the intake
air volume and engine speed, ECM makes compensations
based on input from various sensors to control the optimum
spark-advance and current carrying time.
List of main compensations for spark-advance control and current carrying time control
.
[Control for checking ignition timing]
During basic ignition timing set mode for M.U.T.-III actuator test
function, sparking is done with fixed ignition timing (5
° BTDC)
synchronized with crankshaft position sensor signal.
CompensationsContent
Intake air temperature compensationCompensation is made according to intake air
temperature. The higher the intake air temperature
the greater the delay in ignition timing.
Engine coolant temperature compensationCompensation is made according to engine coolant
temperature. The lower the engine coolant
temperature the greater the advance in ignition
timing.
Knocking compensationCompensation is made according to generation of
knocking. The greater the knocking the greater the
delay in ignition timing.
Stable idle compensationCompensation is made according to change in idle
speed. In case engine speed becomes lower than
target speed, ignition timing is advanced.
Delay compensation when changing shiftDuring change of shift, sparking is delayed
compared to normal ignition timing to reduce
engine output torque and absorb the shock of the
shift change.
Battery voltage compensationCompensation is made depending on battery
voltage. The lower the battery voltage the greater
the current carrying time and when battery voltage
is high current carrying time is shortened.

THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-38
THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE
SPEED CONTROL
M2132003500328
ECM detects the amount of accelerator pedal
depression (as per operator's intention) through the
accelerator pedal position sensor. Based on pre-set
basic target opening angles it adds various compen
-
sations and controls the throttle valve opening angle
according to the target opening angle.
While starting
ECM adds various compensations to the target
opening angle that are set based on the engine cool
-
ant temperature, so that the air volume is optimum
for starting.
While idling
ECM controls the throttle valve to achieve the target
opening angle that are set based on the engine cool
-
ant temperature. In this way best idle operation is
achieved when engine is cold and when it is hot.
Also, the following compensations ensure optimum
control.
While driving
Compensations are made to the target opening
angle set according to the accelerator pedal opening
angle and engine speed to control the throttle valve
opening angle.
AK602236AE
Throttle
position
sensorMain
Main Sub
SubMotor drive circuit
A/C switch (CAN) Engine coolant
temperature sensor
Intake air temperature
sensor
Crankshaft position sensor
Power steering pressure
switch
Generator FR terminal
Transmission range
switch (CAN) Motor drive power supply
(From throttle actuator
control motor relay)
Throttle actuator
control motor
Control unit
Barometric pressure
sensor Accelerator
pedal position
sensor
ECM

THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-39
List of main compensations for throttle valve opening angle and idle speed control
Initialize control
After ignition switch turns OFF, ECM drives the throt-
tle valve from fully closed position to fully open posi-
tion and records the fully closed/open studied value
of the throttle position sensor (main and sub) output
signals. The recorded studied values are used as
studied value compensation for compensating basic
target opening angle when the engine is started next.
CompensationsContent
Stable idle compensation (immediately after start)In order to stabilize idle speed immediately after
start, target opening angle is kept big and then
gradually reduced. Compensation values are set
based on the engine coolant temperature.
Rotation speed feedback compensation (while
idling)In case there is a difference between the target idle
speed and actual engine speed, ECM
compensates the throttle valve opening angle
based on that difference.
Atmospheric pressure compensationAt high altitudes atmospheric pressure is less and
the intake air density is low. So, the target opening
angle is compensated based on atmospheric
pressure.
Engine coolant temperature compensationCompensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature the greater the throttle valve opening
angle.
Electric load compensationThrottle valve opening angle is compensated
according to electric load. The greater the electric
load, the greater the throttle valve opening angle.
Compensation when shift is in D range When transmission is changed from P or N range
to some other range, throttle valve opening angle is
increased to prevent reduction in engine speed.
Compensation when A/C is functioningThrottle valve opening angle is compensated
according to functioning of A/C compressor. While
A/C compressor is being driven, the throttle valve
opening angle is increased.
Power steering fluid pressure compensationThrottle valve opening angle is compensated
according to power steering functioning. When
power steering oil pressure rises and power
steering pressure switch is ON, the throttle valve
opening angle is increased.

HEATED OXYGEN SENSOR HEATER CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-49
HEATED OXYGEN SENSOR HEATER CONTROLM2132007000206
When exhaust gas temperature is low, the heated
oxygen sensor response is dull. So, response is
improved by raising the sensor temperature by pass
-
ing current through the heater at a low exhaust gas
temperature, such as in the immediate aftermath of
the engine start, or during the warm up operation and in cutting the fuel during deceleration. Based on driv
-
ing conditions and the heated oxygen sensor activa-
tion state, ECM changes the amount of current (duty
ratio) to the heater to quicken the activation of the
heated oxygen sensor.
AK602241AD
Battery Heated oxygen sensor heater
Engine coolant
temperature sensor MFI relay
ECM

GENERATOR CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-51
GENERATOR CONTROLM2132025000172
During engine idle operation, ECM controls duty of
conduction between generator G terminal and
ground. (G terminal duty is controlled to be the same
as ON duty of the power transistor inside the voltage
regulator). If headlights etc. are turned on while
engine is idling, the consumed current increases
suddenly, but by gradually increasing the generator G terminal OFF duty, ECM restricts sudden increase
in generator's output current and output current is
increased only gradually. (Battery current is supplied
to the headlamp etc. till generator produces sufficient
current.) Thus, ECM prevents change in idle speed
due to sudden increase of engine load.
AK602242 AD
Engine coolant temperature sensor
Generator G terminal
Generator FR terminal
Generator Crankshaft position sensor
A/C switch (CAN)
Ignition switch-STECM

EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT PURGE FLOW MONITOR
MULTIPORT FUEL SYSTEM (MFI)13A-52
EVAPORATIVE EMISSION CONTROL SYSTEM INCORRECT
PURGE FLOW MONITOR
M2132027200019
The ECM detects whether the fuel vapor leakage
exists or not from the evaporative emission control
system. By the specified pattern within the certain
operation range, the ECM drives the evaporative
emission purge solenoid and the evaporative emis
-
sion ventilation solenoid. This allows slight vacuum
to be produced in the fuel tank.
The ECM measures the vacuum condition through
the fuel tank differential pressure sensor signal. By
comparing the normal (expected) value and the
actual value, the ECM detects whether the fuel vapor
leakage exists or not from the evaporative emission
control system.
AK604139
Evaporative emission
purge solenoid
Evaporative emission
ventilation solenoid
Fuel tank differential pressure sensor
Fuel tank temperature sensor
AB
BatteryMFI relay
ECM Mass airflow sensor
Barometric pressure sensor
Intake air temperature sensor
Engine coolant
temperature sensor
Fuel level sensor (CAN)Fuel
tank
Fuel level
sensor To injector