1990 MITSUBISHI ECLIPSE sensor

- __..--
14-44FUEL SYSTEM- Idle Speed Control
IDLE SPEED CONTROL
RlUU*I,GENERAL DESCRIPTION
If the load changes while idling, the idle speed
control servo is activated according to the preset
control logic to control the air flow that bypasses thethrottle valve, thus maintaining the optimum idle
speed.Fast idle air valve
Idle speed
control servo
Cooiar
To intakemanifoldFrom air
cleanerSpeed
adjustrng screwInhibitor switch
Ignition switch
Coolant temperature sensorThrottle position sensor
Crank angle sensorVehicle speed sensor
Air conditioner switch
Barometric pressure sensor
Power steering oil
pressure switch
Intake air te.mperature sensorIdle position switchIgnition timing adjustment
terminalSelfdiagnosisIdata trans-
mission switching terminal
6FUO796
Input signal reading
-3I9Control modedecision
II
41*
Target speed dataIdle speed control---cIdle speed
feedback controlservo position- Target position data
control
Idle speed controlIdle speed control
servo dnve pulse-Drive pulse setting
Drive pulse setting-servo drive pulse
setting data

--
14-52FUEL SYSTEM - Idle Speed Control
4
Start of deceleration
DLhq ON
position
I*2 to 6
Time sec.6FUO295
II)
0(32180(176)Temperature “C 1°F)6FUO29t
CONTROL WHEN THE ENGINE SPEED IS UNUSUALLY LOWThe followi
gcontrols are provided when the engine speecfalls below
i5;D rpm after the engine has been fully warmed-up
[with engine coolant temperature more than
55°C (131”F)].
(1) During feedback control
The idle speed control servo is activated immediately by a
particular number of angular steps which represent the
feedback correction.
(2) During servo position control
The idle speed control servo is activated to conform to
aposition corresponding to an increased number of steps
(46
steps).DASH POT CONTROL
Control is provided to dampen the extending motion of the
pintle from a certain opening degree, thereby absorbing
deceleration shocks.
(1) Control while cruising
While cruising or racing, the idle speed control servo is
activated to further open the bypass air path corresponding
to the dash pot position which is more open than the idle
position.The idle speed control servo is activated in this way when
the following conditions are met.
l Engine speed 500 rpm or higher
l Idle position switch in the OFF position
The dash pot position is dependent on the throttle valve
opening map value.,
(2) Control during deceleration
When the vehicle is decelerated from a cruising or racing
speed, the idle speed control servo is activated to close the
bypass air path gradually from the dash pot position so that
the intake air volume is not abruptly reduced, thereby
dampening deceleration shocks.
The idle speed control servo is activated when either one of
the following conditions are met.
lWhen the throttle position sensor output voltage drops
l When the idle switch is turned on.
CONTROL WHEN STARTING
While the engine is being cranked, the idle speed control servo
is controlled to provide optimum bypass air volume for starting.
Immediately after the ignition switch is turned on, idle speed
servo position control is provided to achieve the optimum
_
position.

FUEL SYSTEM- Power Supply Control
Battery
L11The engine control unit controls the power
suv ’tcthe sensors, engine control unit and
actuate,A;the control relay.
-P
.
-p.Ignition switch
Inn yr
To air flow sensor,crank angle sensor,idle speed controlsetvo. injectors
Control relay
Relay controlFuel pump
controlIgnitionswitch signal
Enginecontrol
unit
I6FUOl’
Power Supply ControlWhen the ignition switch on signal is input, the
engine control unit energizes the control relay coil
L3to turn on the
S2 switch, thus supplying power to the
injectors, air flow sensor, idle speed control servo,
Fuel Pump ControlWhen cranking the’engine (ignition switch at the ST
position), the engine control unit energizes the
Lcoil to turn on the
S switch, thus activating the fuel
pump.While operating the engine (ignition switch at the
IGposition), the crank angle sensor signal is input to
the engine control unit, which energizes the
L,
etc.Approximately seven seconds after input of
theignition switch off signal, the unit turns off the
Sswitch.
control relay coil to keep the
SI switch on, thus
continuing to activate the fuel pump.
When the crank angle sensor signal fails to be
inputfor 0.6 second or longer due to engine stalling,
.,the engine control unit immediately turns
thz. 5switch off to stop the fuel pump as a safet)
precaution.

FUEL SYSTEM -Air Conditioner Relay Control14-55AIR CONDITIONER RELAY CONTROL
Batterylgnltlon
switch
Air conditionerswitch
@OFF ON
Coolanttemperature
switch
RlUCAAA
/Air condittoner
When the air conditioner switch ON signal is input,
the engine control unit turns the air conditioner relay
ON to activate the air conditioner compressor.
In order to prevent vibrations or engine stalling due
to activation of the compressor, the engine control
unit controls the air conditioner relay so that the
compressor is activated after a predetermined
interval, according to the current operating condi-
tions.For models equipped with the automatic
transaxle,when the vehicle is subjected to acceleration at
which the throttle valve opening is great (throttle-
position sensor output voltage approximately
4V or
more, i.e. throttle valve opening approximately 65
degree or more), the air conditioner power relay
circuit is interrupted for a certain fixed time (approx-
imately five seconds) in order to maintain the
acceleration performance.

14-56FUEL SYSTEM -Supercharge Pressure Control
SUPERCHARGEPRESSURE CONTROL RlWDetonation
sensor
lEngine control
unit
Knockcontrol
ControlrelayIntercooler
h&l --/I- h
.. .Waste gate
P solenoid valve
Air cleaner,
Power
transistorWaste gate
unit
actuatorOf
CT1 +p$?V~~~t
6FUO665
II\Spring set pressure
Turbo pressure acting5Fuo570
on waste gate actuatorWhen using premium-grade gasoline, the engine control unit
functions to switch ON the power transistor, then waste gate
solenoid valve is turned “ON”.
Because there is then a partial leak of the turbo pressure acting
upon the waste gate actuator as a result, the waste gate valve
will then not open unless there is an increase of the turbo
pressure to a level that equals or exceeds the set pressure of
the waste gate actuator spring.
As a consequence, there is sufficient supercharging when
premium-grade gasoline is used, and a high level of output can
be obtained.
If regular-grade gasoline is used, the power transistor is
switched OFF by the engine control unit, thus interrupting the
circuit of the waste gate solenoid valve and stopping the
leakage of turbo pressure.
When the turbo pressure then increases, as a result, to reach
the waste gate actuator spring set pressure, the waste
gate----valve opens.
When regular-grade gasoline is used, therefore, the turbo
pressure becomes smaller, and, coupled with knock control,
the engine is thus protected from the effects of knocking.

FUEL SYSTEMAir Flow Sensor (AFSI Filter Reset Control /- Turbo Meter Control 14-57
AIR FLOW SENSOR (AFS) FILTER RESET CONTROL Engine control unit
I1Air flow sensor
Crank-angle sensorIdle position switch
Throttle position sensor
4Air flow sensor
//\\ -
\Reset terminal
RllruAs
6FlJo664I11When the idle switch is ON, or when the throttleWhen these Signals are input. the air flow sensor
position sensor output voltage is low, the engineresets the modulator. There is a switch to the circuit
control unit functions to switch ON the powerthat lessens turbo noise. This eliminates any error in
transistor, and, as a result, air flow sensor resetmeasuring the
.amount of intake air when there is a
signals are sent to the air flow sensor.change from high speed, high load driving to
deceleration.
TURBO METER CONTROL
Air flow sensor
(AFSI ’
Crank angle sensorEngine control unit
BT
Rl4QAAATurbo meterControl relay
The turbo meter is a current type meter. The engine
control unit receives the intake air volume signal
from the air flow sensor and the rpm
signal from the
crank angle sensor and calculates the engine load.Then, the unit determines the duty ratio according
to the load and drives the turbo meter.
Intake air volume
Duty ratio
it Load 0:rwDuty ratio
The duty ratio is defined as ON time ratio
TJT, of 33.3 Hz pulse.
When the duty ratio increases, average current that flows to
the turbo meter also increases
so that the turbo meter
indicates higher value.
When the duty ratio is decreased, the turbo meter indicates
smaller value.
cI30
msec. 30 msec.1621cm:

._ ..-
14-58
.-FUEL SYSTEM
- Accelerator Components
-7
ACCELERATOR COMPONENTSRlUUAAThe accelerator is the cable type, and the pedal is
the suspended type.
A nylon bushing is installed on the end of the
accelerator cable, preventing contact noise
be-tween the cable and accelerator arm from beinggenerated.
In addition, the accelerator pedal switch, which is
used as a control sensor on models with the4-speed NT, is equipped at the pedal support
member.
CONSTRUCTION DIAGRAM
Accelerator cable
Accelerator pedal
switch
bushing
\Accelerator
cableAccelerator
ahmember
Accelerator
Accelerator
pedal

FUEL SYSTEM -Auto-cruise Control System14-59AUTO-CRUISE CONTROL SYSTEMRIIPA&A
using the auto-cruise control system, the vehicle
oar-rbe maintained at a constant driving speed
[between 40 km/h (25 mph) or higher and 145 km
(90 mph) or lower], as selected by the driver,
without using the accelerator pedal.The actuator is the DC motor-driven type for a high
degree of adherence to the set speed. A flexiblesupport system is used for installation of the
actuator in order to prevent the transaxle of body
vibrations to the actuator.
CONSTRUCTION DIAGRAM
control switchOJAO2SS
Accelerator
Actuator
ab’ea\ A
Inhibitor switch Vehicle speed sensor
(reed switch)
Accelerator cab1e.A/IClutch switch
/Accelerator pedal switch IStop light switch