relay MITSUBISHI ECLIPSE 1990 Owner's Manual

sors and the engine control unit, tooether with
actuators and
related components, and k controlled
according to nine control functions as shown below.
Of these nine, No.
1 and, Nos. 3 to 9 are supplied by
II
EngineSensors - control -unit
r--------‘-1
l--cIFuel-pressureIcontrol valveII
‘4 Fuel DumoI13 I I or-’I
,--c 1. ;;EILT!I;ELSSURE1J
Fuel presJ1regulatorI
- Throttle valve
i
7
_c Speed adjusting
screw
14-2
“GENERALFUEL SYSTEM
- GeneralRl484AB
The fuel system is of the Electronic Control
Multi-point Fuel Injection type, which has an injector forthe engine control unit.
each cylinder. The system comprises various sen-Refer to Group 8 ELECTRICAL for No. 6 IGNITION
TIMING CONTROL.
-Fast idle air valve
- idle speed
control servo-
IrI
- Injectors
- 4. IOLESPEEO
CONTROL
-I5. POWER SUPPLYCONTROLControl relay
-) 6. V$&iRq3NLTIMING- Power transistor
b
-c 7. AIR CONDITIONERRELAY CONTROL- Air conditioner
relay
c-------------Tp----------1
NOTEI
The [‘-,l> is applicable to theI
.-( 8. ZJJ\~RR~LARGING k-- -4 Wastepate
Liturbo only.-----w--------IL solenoid valve--B--------d
Ir-‘---‘---“‘-7c------v--w-1
L’ 9.
-I
‘C;RB;zLETER--A Turbo meterI--------c----J+ L----------a
k’6FU1145

FUEL SYSTEM - General14-3The fuel is supplied under pressure by the in-tanksent to the engine control unit.
type fuel pump, and is injected from injectors into allThe crank angle sensor converts the crank
angle,
cders. The injectors are activated by signals fromthat is, engine turning state into an electric signal
tk, engine control unit, and the amount of fueland sends it to the engine control unit.
injected is determined according to the drivingThe engine control unit, based on these signals,
conditions.determines the basic activation timing of the
injec-The intake air passes through the air flow sensor,
tars. The amount of intake air is determined by the
throttle body, air intake plenum and intake manifold,degree of opening of the throttle
valye,, and during
and finally enters the combustion chamber. The airengine idling, the amount of intake
arr IS regulated
flow sensor detects the amount of air flow and
by the idle speed control servo.converts this data to electric pulse signals that are
EGR temperature sensor (California) 7
Waste gate solenoid valve
Purge control solenoid valve
EGR control solenoid valve Fuel pump relay
Control relay
Air conditioner relay
Diagnosis output
Ignition coil
Control relay (Fuel pump drive
signal)Vehicle speed
SensorIgnition switch “ST” terminal
Ignition switch
‘IG” terminal
Air conditioner switch
Power steering
switch
Inhibitor switch
Idle speed
ontrol servoFast idle
air valve
-Throttle
&r -kilo m-i&inn’Power transistorleturn to-
uel tank- Fuel from
Coolant temperature sensor
Coolant temperature switchFuel-pressure
control valve
Detonation sensor
4

14-14
.._~- ---.FUEL SYSTEM
- Sensors
SENSORSRlUGENERAL DESCRIPTION
The types and functions of the sensors are as listedsend corresponding signals to the engine control
below. These sensors detect engine conditions and
unit.
SENSORSFUNCTION
AIR FLOW SENSOR
fSenses the intake arr volume with a Karman vortex flow meter.
INTAKE AIR TEMPERATURE
SENSORSenses the Intake air temperature (temperature of air at
the point of entry into the air cleaner).I
BAROMETRIC PRESSURE
SENSORISenses the barometric pressure faltrtude) wrth a
semiconductor diffusion type pressure sensor.
$;;OOf;T TEMPERATURESenses the engine coolant tern
THROTTLE
POSITISenses the throttle
tI
IDLE POSITION SWITCHSenses whether or not the accelerator pedal is being
operated with a contact switch.
Senses the top dead center on compression stroke of
NO. 1 and No. 4 cylinders with an LED and photo diode pair.
CRANK ANGLE SENSORSenses the crank angle of each cylinder with an LED
and photo diodepair.
T
OXYGEN SENSORSenses
actrvation of the air con
POWER STEERING OIL
PRESSURE SWITCHc-lSenses the power steering ‘load with a contact switch.
IGNITION SWITCHSenses ON/OFF
posrtion of the ignition switch.I
Senses engine cranking.
,
IGNITION TIMING
ADJUSTMENT TERMINALWhen this terminal is shorted, the ignition timing and idle
speed control servo is set in the adjustrng mode by the enginecontrol unit.
INHIBITOR SWITCHSenses the *P” and “N” positthe automatic transaxle.Senses.
by pieto-electric element,. cylinder block
vibrations that occur when there ISengineknocking.
CONTROL RELAY
(Fuel pump drive signal)
lFnorne ianitron sianal!Senses ignrtton coil prIman/ voltage.

FUEL SYSTEM - Sensors
AIR FLOW SENSOR
IAir
0
Power supplyAir flow sensor(from control relay)
r-- Amplifier Few
L+--J Vortex ITo throttle
bodyEngine control unit
>- Power supply
e5 volts
6FUO493
EC1537
Karman vortex
(1) Slow air flow
6FUO423
(2) Fast air flow
6Fuo42rThe air flow sensor for measuring the volume of engine intake
air uses the Karman vortex phenomenon to detect the air flow
rate. The air flow rate detected in this way is sent to the engine
control unit as data on intake air volume.
Using this signal and the engine rpm signal, the engine control
unit makes computations to determine the basic injection
timing.
A barometric pressure sensor and an intake air temperature
sensor are installed on the air flow sensor.
The air flow sensor consists of the following parts:
l Rectifier:
Rectifies the flow of intake air admitted through the air
cleaner.l Vortex generating column:
Serves to generate Karman vortices.
l Transmitter:
Transmits ultrasonic waves.
l Receiver:
Receives ultrasonic waves.
l Amplifier:
Generates ultrasonic waves.
l Modulator:
Converts ultrasonic waves that have been received into
electric pulses.
l Acoustic material
Karman Vortex
When a triangular column is placed in an air stream, regularly
spaced vortices are generated downstream alternately on
either side of the column. These vortices are called
“Karman
vortices”.The number of vortices generated is proportional to a
cloSedegree to the volume of air flow in a given time; the higher the
flow speed, the more vortices are generated.

--
,
14-24FUEL SYSTEM - Sensors
POWER STEERING OIL PRESSURE SWITCHEngine control unit
Power steering oil
pressure switchBattery
voltage
6FUO5OtIWhen the steering wheel is turned and the oil
pressure of the power steering oil pump increases,
the power steering oifpressure switch sends an ON
signal to the engine control unit. The engine control
unit detects the oil pump load with this signal andactivates the idle speed control servo to control
theidle speed. Specifically, it prevents the idle
speecfrom dropping due to oil pump load, thus
ensuringstable engine idling.IGNITION
SWITCH
1IBattery
Ignition
switch
Starter motor
aS terminalcontrol unit
6FUO762The signal indicating that the ignition switch is ON,
OFF or cranking (ST) is input to the engine control
unit.
When the ignition switch ON signal is input to the
engine control unit, the unit energizes the control
relay coil to supply power to the sensors and
actuators.When the ignition switch ST signal is input to the
engine control unit, it determines that the engine
iscranking and controls the fuel injection rate,
despeed control servo, ignition timing, etc. for
-mum cranking conditions.

I
j:Battery
14-26FUEL SYSTEM - Sensors
INHIBITOR SWITCH The inhibitor switch’s ON (when “N” or
“P”) or OFF (when
other than “N” or
“P”) signals are input to the engine control
unit. The engine control unit, based on these signals, then
determines whether the transaxle is in neutral or is in a drive
range, and then activates the idle-speed control servo so as tc
regulate the idling rpm.
S terminal
---
@
Starter
(Armature)
YT
6FU114!
CONTROL RELAY (Fuel pump drive signal)
This relay senses that power is supplied to the pump.
-If power failed to be supplied to the fuel pump during
er,, .ecranking or during driving, the engine control unit judges that a
fault has occurred and stores corresponding diagnosis code
(No. 42) in memory and at the
sa’me time, causes the engine
alarm lamp (Mulfunction indicator lamp) to come on.IGNITION
COIL (Engine ignition signal)From ignition switchEngine control unit
Ignition
-Elsignal sens-
ing circuit
3)
ffuo573
-
JThis coil senses generating state of the ignition
signal.If abnormal condition occurs during engine
opera-tion such as the ignition signal not being generatedat ignition timing, The engine control unit stores
corresponding diagnosis code (No. 44) in
memoWand at the same time. causes the engine alarm
lamp(Mulfunction indicator lamp) to come on.

‘73.- .-_ _ .-__ .- -..- - .-----___. _____^. -._ __--.
FUEL SYSTEM- Enaine Control Unit14-27
ENGINE CONTROL UNITRI4FhAA
GENERAL DESCRIPTIONEngine control unit
~
~~:~~~~~~~~~:~~
~. . . . .. .. . . . ... . . . . ... .. :+:.:.:.:.:.:.:.~.:.~+~.
6FUO76The engine control unit consists of an
8-bit micro
computer, a random access memory, a read only
memory and an input/output interface.
It determines the engine operating state based on
various information (input
signals) it receives fromthe sensors described earlier, and then controls and
activates the necessary actuators as shown in the
table below to achieve optimum engine operating
conditions.
Engine control unit
Control items
Fuel injection control
Idle speed control
Power supply control
A&;;;ditioner relay
Ignition timing control
SuTpuegohzrging control
$r;ir;;ter control
Fuel pressure controlControl contents
For controlling injector driving timing
and duration based on multipoint’sequential injection.
For controlling bypass air quantity foridle speed control by activating the
idle speed control servo.
I3 Idle speed control
servo
For controlling power supply to the
sensors and actuators by controlling
the control relay.For controlling the
ON/OFF position of
the air conditioner relay.For controlling the ignition timing.
For controlling the supercharging pres-sure by regulating of the waste gate
actuator activation pressure.
For controlling the turbo meter and
displaying the supercharge pressure.
3 Ai;acenditioner
Power transistor
1

FUEL SYSTEM- Engine Control Unit14-29
SFUllSOTerminal
ConnectionTerminalConnectionNo.
No.
1Self-diagnosis output53EGR control solenoid valve (California only)
2Diagnosis/data transfer select terminal54Power transrstor for No. 1 and No. 4 cylinder
‘3Turbo meter
55Power transistor for No. 2 and No. 3 cylinder
4Oxygen sensor56Control relay (Fuel pump control)
5Power steering oil pressure switchl 57Fuel-pressure control valve
6Idle position switch58Coil “Al ” for idle speed control servo
7Air conditioner switch59Coil “A2” for idle speed control servo
8Intake air temperature sensor60No. 3 injector
l 9Detonation sensor61No. 4 injector
10Air flow sensor62Purge control solenoid valve11
-63Control relay
12Ignition timing adjustment connector64Engine warning irght (Malfunction indicator light)
13Control relay (Fuel pump drive signal)65Air conditioner relay
l 14Air flow sensor active filter reset66Control relay
15EGR temperature sensor (California only)67Coil “Bl ” for idle speed control servo
16Barometric pressure sensor68Coil “B2” for idle speed control servo
17Sensors ground101Ground
18Vehicle speed sensor102Power supply
19Throttle position sensor103Power supply for backup
20Coolant temperature sensor
104Inhibitor switch
21Crank angle sensor‘105
Waste gate solenoid valve
22Top dead center sensor106Ground
23Power supply for sensors (5 volts)107Power supply
24Sensors ground108“ST” terminal for ignition switch
51No. 1 injector109Ignition pulse detect
52No. 2 injector170“IG ” terminal for ignition switch
NOTETerminals indicated by the l symbol are applicable only to turbo models.

14-30SELF-DIAGNOSISFUEL SYSTEM- Engine Control Unit
There are 16 diagnosis items, as listed below; the
diagnosis results are stored in computer memory.The diagnosis memory is maintained by backup
The stored results can be ready by connecting apower from the battery (not by way of the ignition
circuit tester or voltmeter to the diagnosis
connec-switch) so that it will not be lost even if the ignition
switch is turned OFF.
tor.
DiagnosisOutput pattern
codeEl
None
lP
@ 11l-l
@ 12n@ 13
@ 14
@ 21Ul n
Diagnosis items
Faulty computer in the engine control unitMalfunction of the air/fuel ratio control system
Open or short circuit in the oxygen sensor circuit
Open or short circuit in the air flow sensor circuit
Open or short circuit in the intake air temperature sensor
circuit
Open or short circuit in the throttle position sensor circuit
Open or short circuit in the engine coolant temperature sensor
circuit
022u1 nn
No voltage change of the crank angle sensor signal
,
@
23
u u-inn
No voltage change of the TDC sensor signal
24uu-uvinnnnNo voltage change of the vehicle speed sensor signal
Q25uuuuuunnnnnOpen or short circuit in the barometric pressure sensor
2 31I-~-~---~ nOpen circuit in the detonation sensor circuit
@ 41uuul nOpen circuit in the injection circuit
042UUuLJul
Malfunction of the control relayOpen or short circuit in the fuel pump drive circuit
z 43UUULnlulMalfunction of the
EGR system
Open or short circuit in the EGR temperature sensor circuit
%4u u u uvinnOpen circuit in either of ignition coil circuit
0nNormal (with none of above faults)
. IA-r-NUltl 1: l 2: for California@ denotes items indicated by an illuminated engine warning light

FUEL SYSTEM- Fuel Injection Control14-35INJECTOR CIRCUIT
,Battew
Control relay
Resistor

No.Injector
Engine control unit
6FU0516Electricity from the battery flows to the control relay
and then to the resistor (turbocharger-equipped
models only), the injector, and the engine control
unit.Upon reception of the fuel injection signal, theengine control unit causes the power transistor to
be turned ON, thus completing the injector ground
circuit. In this situation, current flows to the injector,
which injects fuel while the power transistor is ON.