1990 MITSUBISHI ECLIPSE fuel type

3-d__- .
FUEL SYSTEM
-Idle Speed Control14-45IDLE SPEED CONTROL SERVO
L
PtntleThrottle bodv
Idle speed control
servo
Extend
7 -IMagnet rotordoil
/Stepper motor
6FUO799The idle speed control servo, consisting of a
steptype motor and pintle, is mounted on the throttle
body. As the motor operates, the pintie extends or
retracts to control the bypass air flow.
The step type motor, or stepper motor, is a motor
that rotates a fixed angle when an electric
Pulse is
rpplied.The rotor of the stepper motor used here rotates
15degrees whenever a pulse is applied.
The pintle meshes with the lead screw on the
magnet rotor shaft, as shown in the above
illustra-tion. When the rotor rotates in the direction of the
outlined arrow, the lead screw causes the pintle t0
retract towards the interior of the motor. When the
rotor rotates in the direction of the solid arrow, the
pintle extends.

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

14-74
_ ,.-..FUEL SYSTEM
- Auto-cruise Control System
When Canceled by the Stop Light Switch (broad
solid-line arrows)
The stop light switch is a four-pole type that
integrates the switch for the stop light (NO) with
that for the auto-cruise control (NC).
When the brake pedal is depressed, the contacts forthe auto-cruise control (NC) open, cutting off the
circuit to energize the electromagnetic clutch coil.
At the same time, the contacts for the stop light
(NO) close to allow a cancel signal to be input from
the
12-V power supply of the control unit to the
cancel circuit and to the microcomputer. As a result,the transistor which energizes the actuator electro-
magnetic clutch coil turns OFF and the electro-
magnetic clutch coil grounding circuit is cut off, thus
canceling the auto-cruise control mode.
When Canceled by the Clutch Switch (thin
solid-line arrows)
When the clutch pedal is depressed, the clutch
switch is turned ON and the battery voltage is
applied to the cancel circuit of the control unit. then,a cancel signal is input to the microcomputer.
causing the transistor that energizes the actuator
electromagnetic clutch coil to turn OFF. This results
in the electromagnetic clutch coil grounding circuit
bma$ndge cut off, which cancels the auto-cruise control
When Canceled by the Selector Lever (position“N”) (dotted-line arrows)
When the transaxle control selector lever is placed
in the “N” (neutral) position, the inhibitor switch is
turned ON and, as a result, current flows from the
control unit to the inhibitor switch, starter, and
ground. Then, a cancel signal is input from the
cancel circuit to the control unit, causing the
transistor which energizes the actuator electro-
magnetic clutch coil to be turned OFF. As a result,
the electromagnetic clutch coil grounding circuit is
cut off and the auto-cruise control mode is canceled.Although a small current (voltage 5 V) flows through
the starter, it is not activated.
MAIN switchLIMIT SWITCH
The function of the limit switch is to shut off the flow of current
to the motor and apply an electric brake to quickly stop the
motor if the throttle valve becomes either fully open or fully
closed, thus preventing problems which might be caused by an
overload of the motor.
The illustration at left shows the condition of the limit switch
when the throttle valve is fully closed, indicating that
.limitswitch
(1) is in the OFF and the RELEASE circuit is being
deenergized.
IAutocruisecontrol unit
07Aool'
.-

_-.-, ._ u .-, 4. ::; bt-i 3,. F-7__ . ._,_ _ ” -- --.-....
FUEL SYSTEM- Auto-cruise Control System14-75INTERMEDIATE LINKS
Intermediate
iink A(accelerator pedal side)Accelerator cable
A
(accelerator pedal side)
03AO224During Auto-cruise Control Driving
The rotation of the selector causes intermediate link
B to turn
which opens and closes the throttle valve. However, intermedi-
ate link A is not operated and accelerator cable A does not
move, so the accelerator pedal remains stationary in its original
position.During Normal Driving
When the accelerator pedal is operated, the rotation of
intermediate link A, which is connected to accelerator cable A
(accelerator pedal side), causes intermediate link
B to turn, and
accelerator cable
B, which is connected to intermediate link B,then opens and closes the throttle valve.
N
0
s -?s
*=Auto-cruise
control unit
13AOO62Vehicle speed
sensor07Aml
VEHICLE SPEED SENSORThe vehicle speed sensor functions to send pulse signals
[which are proportional to the rotation speed (vehicle speed) of
the transaxle’s output gear] to the control unit. The vehicle
speed sensor is installed within the speedometer.
The vehicle speed sensor is the reed switch type; it generates
four pulse signals for each rotation of the output gear. This
sensor is also used in common for other electronic control
systems.

- -----.--..
14-76FUEL SYSTEM -Auto-cruise Control System
Ignition switch
IGI
9
RESUActuator electro-
Microcomputer
1 T 1
rn’Auto-cruise control unit
Autocruisecontrol switch
IGlMAIN
;FF -+++&Control unit
power supply
terminal voltage
03AO264NC: Normally closed
07*0040
AUTO-CRUISE CONTROL SWITCH
The auto-cruise control switch is built into the steering column
switch.MAIN SWITCH
The MAIN switch is an automatic reset type switch to turn ON
and OFF the power supply of the control unit.
COMMAND INPUT SWITCHES (SET and RESUME)
The SET and RESUME switches function to input the control
signals of the auto-cruise control system; both are the
automatic-reset type.
These switches are ON while pressed and OFF when released.
For the ECU’s input interface, each of the input terminals is
pulled up by the battery voltage; the terminal voltage is LOW
level
(OV) when the switch is ON, and is HIGH level (about 12V)when the switch is OFF. These voltage changes (digital
sig*)are input to the microcomputer as ON and OFF signals
o.:
switches.
.

-- --.-*-.e *._,_-.&” :,.>~‘c,-.y~~ 7, . . --
FUEL SYSTEM- Auto-cruise Control System14-77
(For stop light)
OFF +-ON
0N -+-OFF
(For auto-cruise control)
16RO99r4 3
12
NCNO-w-w
I/0l-COFFOFF*~ON4
321NO: Normally opened
NC: Normally closed
07AOOl:
CANCEL SWITCHESThe cancel switches consist of the stop light switch, the clutch
switch, and the inhibitor switch
(“N” position).
The auto-cruise control operation is canceled if any one ofthese switches functions.
STOP LIGHT SWITCH
The stop light switch is a four-pin type of stop light switch thatcombines the switch for the stop light (NO) and the switch for
the auto-cruise control
(NC).When the brake pedal is depressed, the contacts for the
auto-cruise control (NC) open, the supply of current to the
actuator magnetic clutch is cut off, and the fixed-speed drivingmode is canceled.
At the Same time, the closure of the contacts for the stop lightcauses a cancel signal to be sent to the control unit, and within
the control unit the current supply to the actuator magnetic
clutch is stopped, thus causing the cancellation of the
fixed-speed driving mode.
CLUTCH SWITCH
The contacts of the clutch switch close when the clutch pedal
is depressed, with the result that the cancel signal is sent to
the control unit, thus canceling the fixed-speed driving mode.
INHIBITOR SWITCH
The inhibitor switch is a switch also used in eommon as the
switch for the starter.
If the selector lever is set to the “N” position during
fixed-speed driving, current flows from the control unit to the
inhibitor switch and then to the starter and to ground, with the
result that the cancel signal is input to the microcomputer and
the fixed-speed driving mode is canceled.