low oil pressure MITSUBISHI ECLIPSE 1990 Service Manual

-----. _-- ___ELECTRICAL
- Engine Electrical8-27IGNITION TIMING CONTROL SYSTEM
Air flow sensor
Engtne control unit
Intake air temp. sensor
Barometric pressure sensor
Engine coolant temp. sensorIdle position switch
:+
Top dead center sensor
Crank angle sensorVehicle speed sensor
;+Ignition switch “ST” terminal
Detonation sensor for
turbo engine only
Battev
4 Power= tranststor “B”P Ignition coil
109
_
I
1
12a”- To tachometer
Terminal for engine speed detection
Terminal for ignition,timing
and idle speed adjustment
6FUoE.45The ignition control system uses the engine control
consideration the operating conditions of the
en-unit, that judges which cylinder is to be fired at what
gine. The functions and controls of the engine
time based on the signals coming from variouscontrol unit are described in the following page.
sensors. The engine control unit activates the
The constructions and functions of the various
power transistors so that ignition occurs, taking into
sensors are described in GROUP 14.

8-30ELECTRICAL - Engine Electrical
Ignition Advance Angle Control
While
cranking
Fixed angle(5”BTD.C)Engme coolantBarometnc‘-Intake air 1temperaturepressuretemperaturesensorsensor, sensor
Dunng normal operatlon4i+
Advance angle map valueEngine
coolantBarometricIntake airaccording to engine speed4and intake air volumetemperature- pressure__c temperature 4
correctioncorrectloncorrectton
Durtng ignition tlmmg adjustment
Fixed angle(5”BTDC)
c
=ower transistor
-$To ignition
coil
s
6EL0066The engine control unit has the ignition advance
angle value for all cylinder stroke intake air volumes
(engine load) and engine speeds stored in its
memory; this is called the basic ignition advance
angle. The control unit makes corrections in this
value according to the engine operating conditions
such as the engine coolant temperature, barometric
pressure (altitude) and intake air temperature to
obtain optimum advance angle for current engine
conditions. At the engine start and during ignition
timing adjustment, however, it is set to preset fixed
timing.
(1) WHILE CRANKING
When cranking, the ignition advance angle is fixed at
5”BTDC in synchronization with the crank angle
signal.(2) DURING NORMAL OPERATION
Basic ignition advance angle:
Map values that have been preset for all cylinder
stroke intake air volumes (engine load) and engine
speeds.Engine coolant temperature correction:
The engine coolant temperature sensor detects the
engine coolant temperature and when it is low, the
-ignition timing is advanced to improve driveability.
Barometric pressure correction:
The barometric pressure sensor detects the
barometric pressure and determines the altitude.
When the pressure is low (i.e. when the vehicle is at
a high altitude), the ignition timing is advanced to
secure maximum driveability.
intake air temperature correction:
The intake air temperature sensor detects the intake
air temperature and when it is low, the ignition
timing is delayed to prevent knocking in cold
weather. When it is high, the timing is also delayed
to prevent of knocking.
(3) DURING ADJUSTMENT OF IGNITION TIMING
When the terminal for ignition timing and idle speed
adjustment is shorted to ground, the ignition timing
is set at
5”BTDC in synchronization with the crank
angle signal, If the ignition timing does not agree
with the reference ignition timing of 5’BTDC, turn
the crank angle sensor to adjust the timing so that
the crank angle signal agrees with the reference
ignition timing. When the engine speed is approx-
imately 1,200 rpm or higher, however, the timing
advance is according to normal operation and
therefore this ignition timing adjustment is not
available.
-
. .1-_ .---

Knocking Control for Turbo Engine OnlyEngine coolant tern.Advance mapperarure correctton
value- Barometric pressurecorrectton
DelonaIlon
sensorI
lgnmon codKnockmg correcllonprimary currenr
v
Knock wbral+onKnockmg LevelDelay anglelgnmon tlmtngdetemon- delermonmon - calculallon - derermmatlon
II
Y
FatlureIdeIeclton
6FUO565Engine knocking is detected and the ignition timing
is controlled accordingly to prevent continued
knocking and to protect the engine.
When knocking is detected, the engine control unit
delays the ignition timing according to the signal
from the detonation sensor until the knocking is
eliminated (up to a maximum 12” in crank angle). In
the case of an open or short circuit of the detonationsensor harness. the timing is delayed by a fixed
angle (approximately 8” in crank angle) to prevent
knocking.Energization Time Control
While
crankinaIf knocking continues, the advance angle map value
is corrected gradually in the delay direction.
In the absence of knocking, the map value is
corrected gradually in the advance direction. In this
way, optimum ignition timing is constantly control-
led; this control is effective even when fuels of
different octane ratings are used.
This means that the engine is protected from
knocking damage even when the fuel is switched
from premium to regular or vice versa.
Synchronizedwith crank angle
sensor signalcDuring normal operation
Map value
cor-Energizatlon time
responding to- is clipped at 75% of
battery voltageignition interval
IIn order to obtain stable ignition energy, the
ener-gization time of the ignition coil primary current is
controlled as to keep current at a constant value
when the primary current is shut off.
(1) DURING NORMAL OPERATION
Basic energization time
:The increase of the ignition coil primary current
changes with the battery voltage. Therefore, the
energization time is so controlled that the primary
current at time of ignition becomes
6A. The basic
energization time is so set that it is longer when the
battery voltage is low and is shorter when the
6FUO548Energization time clip:
The new two-coil ignition system has its ignition
interval doubled when compared to the convention-
al single
coil type, allowing a longer clip time. As a
result, a long energization time is secured for
sufficient ignition energy even during high speed
operation.
(2) WHILE CRANKING
When cranking, the ignition coil is energized in
synchronization with the crank angle signal.
-

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jl
1 /
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_. ---“._ _ _ ._ ..-..+_LI_y_--- -
9-2ENGINE- General Information
GENERAL INFORMATION
MAJOR
SPEClFlCATiONS
Row- -
Items
Number and arrangement of cylinderCylinder bore x stroke
mm (in.)
Total displacementcc (cu.in.1Compression ratio
Combustion chamber
Valve mechanismNumber of valve
Intake
Exhaust
Valve timing
IntakeOpen/CloseExhaust Open/Close
Lubrication
Oil pump
Fuel system
SuperchargerCooling system
Water pump
Alternator
Starter motor
Ignition system
Exhaust gas recirculation systemCatalytic converter
Crankcase ventilation system
Evaporative emission control system
Non-Turbo engineTurbo engine4 in-line, longitudinal
4 in-line, longitudinal
85 x
88 (3.346 x 3.465)85 x 88 (3.346 x 3.465)1997 (121.9)
1997 (121.7)
9.07.8
Pentroof typePentroof type
Double overhead camshaftDouble overhead camshaft
(DOHC)(DOHC)
88
88
26 “BTDU46”ABDC21”BTDC/Sl”ABDC56BBDUS”ATDC55”BBDUS”ATDC
Pressure feed-full flow filtrationPressure feed-full flow filtration
Gear typeGear type
Electronic control multipoint
fuelElectronic control multipoint fuel
injectioninjection
Turbo typeLiquid cooled-forced circulationLiquid cooled-forced circulation
-Impeller typeImpeller type
AC generator with a built-involtage regulatorAC generator with a built-in
voltage regulator
Planetary gear reduction drivePlanetary gear reduction drivetype
Two-coil type, electronic controlTwo-coil type, electronic control
ignitionignition
Conventional type: For FederalConventional type: For Federal
and Canadaand Canada
Electronical control type:Electronical control type:
For CaliforniaFor CaliforniaMonolithic type,
under-floorMonolithic type, under-floor
installationinstallation
Closed typeClosed type
Charcoal canister typeCharcoal canister type
I

5-jENGINE- Base Engine9-15Operation of the Lash Adjuster
When the valve starts opening
/f-b
During the valve opening stroke
n
6EN0254
When the valve coiqpletesthe opening stroke
6EN0257
6EN0256
(1) Before the valve starts opening:
--
No external load is applied to the
plunger, thus
causing the plunger to be pushed UP
by theplunger spring, maintaining zero clearance.
.(2) When the valve starts opening:
When the cam pushes the rocker arm, the ball inthe high-pressure chamber immediately is held
pressed against the seat by the hydraulic press-
ure. fully closing the high-pressure chamber. AS
the check ball closes, the pressure in the
high-pressure chamber surges causing the plun-ger to support the load from rocker arm, which
.allows the valve to start ooenino.
- -__
(3) During the valve opening stroke:
A very small amount of oil leaks through the
clearance between the lash adjuster body and
plunger.
(4) When the valve completes its opening stroke:
There is no external load being applied to the
plunger as the valve closes, causing the plunger
to be pushed up by the plunger spring. This
causes the pressure in the high-pressure cham-
ber to be lowered, which pushes the check ball
open. The oil which has leaked is replaced in thehigh-pressure chamber from the reservoir cham-
ber.
-

9-16ENGINE- Base Engine
Hydraulic Flow to Lash Adjusters
To lash adjuster onthe exhaust side
P
)
5-Valve body
.Lash adjuster
6EN0107
:.-.
2:.
4
‘.’Relief plunger
I?.,:.:.;
/Lash adjuster
-Cylinder head bolt hole
PlugTo
tash adjuster onthe intake side
Relief spring
-Valve body
6EN0108The oil moves through the cylinder head bolt hoie to
the oil passages drilled in the cylinder head. Andthen has its pressure regulated by the valve body k
pressure regulator) and is supplied to each
la:
adjuster.
-:

,_-.._-~_._. I _ ‘... ----
ENGINE- Base Engine9-19
Reservoir
chamber/
Reservoir
chamber
PressurechamberOperation of the Auto Tensioner
WHEN THE BELT TENSION HAS INCREASED
(1) The tensioner arm pushes the piston in the direction shown
by
arrow @, causing the hydraulic pressure in the pressurechamber to build up.
(2) The check ball closes.
(3) The oil inthepressure chamber is compressed by the
piston, which causes a small amount of oil to gradually leak
through the clearance between the piston and cylinder into
the reservoir chamber. This causes the piston to move
slowly in the direction shown by arrow
@.
(4) The piston stops moving when the load in the direction @balances the spring tension, which determines the load,
i.e., tension, applied to the belt.
WHEN THE BELT TENSION HAS DECREASED
(1) The piston moves in the direction shown by arrow @I by the
spring tension.
(2) As the piston moves, the hydraulic pressure in the pressure
chamber becomes lower than that in the reservoir cham-
ber.
(3) The check ball opens.
(41 Oil enters the pressure chamber.
(5) The piston stops moving when the belt tension balances
the spring tension, which determines the tension applied to
the belt.
_ . _ ---___- -

9-20ENGINE- Lubricathn System
LUBRICATION SYSTEM
nasllOil cooler*
r-4--I-
(oil pressure regulator)
I
n I-1Oil filter
pressureswttch
NOTE
l
: Turbo6LUOO43The lubrication system is the pressure-feed, full-
flow filter system. The engine oil sent under
pressure by the gear-type oil pump is filteredthrough the cartridge-type oil filter before being
delivered to the various engine parts.
SPECIFICATIONS
ItemsOil pump
Type
Delivery rate
Relief valve opening pressure
Oil pressure switch
Type
ON pressureOil filter
Specifications
Gear type
10 cm” (.Sl cu.in.)/engine revolution
550 kPa (78 psi) or more
Contact-point type
30 kPa (4.3 psi) or less
Cartridge type

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

14-6FUEL SYSTEM -Fuel Supply and Fuel Pressure Control
intake manifold/I\
Engine
Fuel
03AOOlOThe fuel supply system comprises electromagnetic
type injectors, a delivery pipe, a fuel pressure
regulator, a motor-driven fuel pump, and the engine
control unit, which activates and controls the injec-
tors and fuel pump based on data supplied by the
various sensors.
After being filtered by an in-tank filter, the fuel is
pumped from the tank and is filtered again by an
external filter before it is distributed to the injectors
through the delivery pipe. The pressure of fuel
delivered to the injectors is regulated by the fuel
pressure
reoulator; excess fuel after pressure reg-ulation has been performed is returned to the fuel
tankThe injectors are activated on command from the
engine control unit and inject the fuel to each intake
port of cylinder head sequentially according to the
predetermined ignition order.
In addition, a fuel-pressure control valve has been
equipped in order to maintain idling stability of turbo
models immediately after restarting under high- -
temperature conditions.
The fuel tank is located under the floor of the rear
seat, thus giving it protection in the event of a
rear-end collision. A fuel pump drive terminal is
provided in the engine compartment for greater
serviceability.
-
SPECIFICATIONSItems
Fuel pump
Type
Delivery rate
liters (gals.VHr
Delivery pressurekPa (psi)
Fuel pressure regulator
Tvw
Regulated fuel pressurekPa (psi)
Fuel filter
Rated flow rate
liters (qts.)/min.
Filter areacm’ (in.‘)
Injectors
TypeCoil resistance
n

--
.- -_-_
SpecificationsMotor-driven, in-tank type
Minimum 90 (23.8)
450 - 600 (64 - 85)
Diaphragm type
335 (47.6)
255 (36.3)
2
(2.1)
1,500 (233)Solenoid type
,.13-16
2-3
I