sensor MITSUBISHI ECLIPSE 1990 Workshop Manual

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 <Turbo>
SUPERCHARGEPRESSURE CONTROL <Turbo>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> /- Turbo Meter Control <Turbo>14-57
AIR FLOW SENSOR (AFS) FILTER RESET CONTROL <Turbo>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 <Turbo>
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
<MBITNylon
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 <mh/&
Vehicle speed sensor
(reed switch)
Accelerator cab1e.A/IClutch switch <M/T>
/Accelerator pedal switch <A/T>IStop light switch

-.
14-60FUEL SYSTEM - Auto-cruise Control System
SYSTEM BLOCK DIAGRAM
---
f?,: 0,
,’
vi
switch cpJT>
Auto-cruise control switch. MAIN switchl SET (COAST) switchl RESUME (ACCEL) switc
I
Intermedi-ate linkActuator
mechanismCOMPONENT PARTS AND FUNCTION OUTLINE
Component part
Vehicle speed sensor
6\uto-cruise control unit
Function
Converts vehicle speed to pulse,
Receives signals from sensor and control switches; microcomputercontrols all auto-cruise control functions
ActuatorRegulates the throttle valve to the set opening by signals from the
auto-cruise control unit
Control switchMAIN switch
Switch for auto-cruise control power supply
SET
(COAST) switchControls auto-cruise control functions by SET (COAST) and
1 RESUME (ACCELIRESUME (ACCEL) switch
Cancel switch
Stop light switchClutch switch
<M/T>Outputs the auto-cruise control cancel signals
Inhibitor switch CA/T>
Accelerator switch
<A/T>During constant speed driving, the accelerator pedal is inactive and
the accelerator switch is turned ON.
Therefore, OFF signal is output from the auto-cruise control unitto the ELC
4A/T control unit during constant speed driving only.
4-I-Ed automatic transaxle control unitControls overdrive ON and OFF based on overdrive ON andOFF signals from the auto-cruise control unit for the auto-cruise
controlAuto-cruise indicator lightThis indicator light illuminates to indicate that the vehicle is
traveling in the auto-cruise mode.
Diagnosis connectorBY connecting a voltmeter control unit diagnosis and input-check
codes can be read out (for details, refer to P. 14-69).

F
FUEL SYSTEM -Auto-cruise Control System'l4-61
AUTOCRUISE CONTROL UNIT
Je auto-cruise control unit incorporates a micro-computer which provides the set coast, resume,
acceleration, cancel, low-speed limitation,
high-speed limitation, overdrive OFF control, and
auto-
matic cancellation functions. The microcomputer
inputs signals from the vehicle speed sensor and
the switches, and outputs Control signals to the
actuator’s DC motor, the electromagnetic clutch,and the automatic
.transaxle (4 A/T) control unit in
accordance with the programming (software) of themicrocomputer.
CONTROL LOGIC BLOCK DIAGRAM
--
Auto-cruise control UnitIgnitionswitcha.-.
I
Input interface circuit
piz7q.f~~
I
L
Micro-
computer
jutput interface circuitIr--lI----
--7I IActuatorI
Electromagnetic
clutch coil
OD-OFF out-
put circuit
NC: Normally closed

14-70
-_FUEL SYSTEM
- Auto-cruise Control System
Display when vehicle speed is approximately
20 km/h (12 mph) or higher, or before the
auto-cruise conrrol system is set
12AolO
NOTE1. Codes indicated by thel symbol are displayed, if
tt-conditions are satisfied, even if the system is normal.
I,.either case, the system is normal if it can be reset.
2. Diagnosis codes are displayed when, after cancellation of
the auto-cruise control system, the vehicle speed de-
creases to less than approximately 20 km/h (12 mph), and
are erased by switching OFF the ignition switch or the
MAIN switch. After the diagnosis codes in the memory are
erased, if (when the power supply of the electronic control
unit is switched ON once again) the power supply of the
electronic control unit is normal, continuous ON/OFF
signals will be displayed at
O.&second intervals, regardless
of whether the system condition is normal or not. (Refer to
the illustration at the left.)
INPUT-CHECK FUNCTION
The input-check function allows you to check if the input signal
is normal when a cruise control failure occurs, including the
situation where the cruise control cannot be set.
(1) Connect a voltmeter to the diagnosis connector of the
junction block.
(2) Operate the SET and RESUME switches simultaneously.
(3) Turn ON the ignition switch; the input check can now be
carried out. Perform the corresponding input operations to
read the output codes.
Output codes
Display patternsInput
operationCheck resultst
y- 0.5sec.
n
SET switch ONSET switch circuitis normal.RESUME switch circuit
is normal.
Each cancel switch ON1. Stop light switch
(brake pedal depressed)2. Clutch switch
(clutch pedal depressed)3. Inhibitor switch ON
(shift lever to “N” position)Each cancel switch
circuit is normal.
Driving at approx. 40 km/h
(25mph) or higherWhen both No. 24 andNo. 25 can be con-firmed, vehicle speed
sensor circuit is
normal.Driving at less than approx. 40
km/h (25
mph). or stopped
NOTE1.If two or more input operations are performed at the same time and the microcomputer receives the corresponding
signals, their output codes are indicated repeatedly in code number order as long as the corresponding signals are
2.input.If the input operation is canceled while the output code is being indicated, the code continued to be indicated until it
completes a display cycle. If the code does not disappear, the switch or harness is probably defective.

_-.-, ._ 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.