fuel MITSUBISHI ECLIPSE 1990 User Guide

ENGINE - Base Engine
ROCKER ARM
(1) The cam follower of the rocker arm is a roller with nea,.,-
bearings.
v
,I$- I- ‘Roller
Needle bearing6ENOlOI
6EN025-4
2-valve SOHC slipper type
9O-valve DOHC roller type1
02.5005.000Engine speed
rpm6ENOl o(Camshaft
I-Oil passage ,
EIr(2) A jet of oil spurts onto the contact area between the cam
and roller from an oil jet located on the fulcrum side of the
rocker arm.
(3) Since the roller rotates as the cam rotates, friction loss is
drastically reduced as compared with the conventional
slipper type.
(4) Due to the construction of the roller rocker arm, the valve
train driving torque is reduced to about half that of the
conventional slipper type, which is equivalent to, or
compares favorably with, the
2-valve SOHC slipper type. All
these factors contribute to enhanced engine performa
and fuel economy.
LASH ADJUSTER
,The hydraulic lash adjuster is of the end pivot type. It eliminates
the need for adjustment of the valve clearance. There are four
lash adjusters provided for each cylinder, 16 in all.
Rocker anIF=Lash adjuster
-
Cylinder head
--Valve
‘-Reservoir chamber
6E NO255
-6EN0256

---
14-1
FUEL
RWA---
ACCELERATOR COMPONENTS
.72
Auto-cruise Control Switch
:.............. 77
Self-diagnosis and Input-check Functions
injector................................................................34
PRESSURi
CONTROL ............................................................
31
Fuel Tank............................................................i
injector................................................................
Specifications
izi
INTAKE
il
Coolant Temperature Sensor
;iI
General Description
: .................... 24
ignition Timing Adjustment Terminal ............
CA/T>.................................... 26
i:
..........
.-.---__-...- -.---.

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

FUEL SYSTEM- duel Supply and Fuel Pressure Control
FUEL SUPPLY AND FUEL PRESSURE CONTROL
GENERAL DESCRIPTION
Fuel tankFuel gauge unitIOJAOt26
Fuel presbreregulator
Fuel gauge
Fuel tankunit - -IEngine control\I
unit
Fuel pumpcheck terminal\
TLo-way valve
Fuel p&sure
regulatorOUO227
RIUXAB

_ --_-_ .-..__FUEL SYSTEM
-Fuel Supply and Fuel Pressure Control14-5Canister
Fuel tank
Fuel pumpcheck terminal
\
Check valvePurge control
valve
\Fuel injectorDelivery
pipe
Fuel p:essure
regulator

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

FUEL SYSTEM -Fuel Supply and Fuel Pressure Control14-7FUEL TANK
m/ithin the fuel tank are the electric fuel pump, the
.ank filter, and the fuel gauge unit.
-I he fuel tank has the following features:
lThe fuel tank is located below the rear seat floor,thus giving it protection in the event of a
rear-end collision.
<2WD>l The fuel tank is located under the engine
compartment floor instead of installing it under
the rear seat floor where the rear axle is located.
<4WD>lA reserve cup is provided within the fuel tank so
!Detailed view of reserve cup
t2WD>Detaiied view of reserve cup
t4WD>
Fuel03AO267
Fuelthat fuel supply is smooth even when there is
only a small amount of fuel remaining.
lA baffle plate arrangement is used at the proper
place within the fuel tank in order to prevent the
generation of abnormal noise caused by the
undulation movement of the fuel.
l A chipping-protection coating has been applied
at the lower part of the fuel tank in order to
protect the tank from damage by pebbles, etc.
thrown up from the road surface, and from
subsequent corrosion.
lA fuel pump and fuel gauge unit assembly has
been adopted which incorporates the fuel pump
and the fuel gauge unit in one.
<4WD>l A drain plug has been provided in order to
improve serviceability.
Thermistor (for low
fuel warning light)In-tank filter
Fuel tankI
e
/ 03AO268
Drain plug
assembly

14-8
rFUEL SYSTEM
-Fuel Supply and Fuel Pressure Control
FUEL PUMP
This fuel pump is known as the in-tank type becauseit is located within the fuel tank itself, surrounded by
the fuel. For this reason, the pump operation noise
is well insulated, and it has excellent resistance to
vapor-locks.This type of pump is also called the “wet type”
because even its internal parts are in contact with
the fuel. With a construction that is the unification of
a ferrite-type DC motor and an impeller-type pump,
the pump itself is composed of the impeller, which
is driven by the motor, as well as the casing and the
cover. There are, in addition, a relief valve (a safety
valve for protection of the fuel-pressure circuit) and
a check valve (to maintain residual pressure).
The electric fuel pump has the following features:
l It has greater discharge pressure
mechanical-type fuel pump, as wellthan a
as lessdischarge pulsation.
lIt has a lower level of operation sound that the
electromagnetic type (Bendix type) of fuelpump.
PRESSURE-SUPPLY OF FUEL
When the impeller is caused to rotate by the motor,
a pressure differential develops at the upper. and
lower parts of the impeller, caused by the grooves in
the circumference of the impeller.
When this happens, a whirlpool effect is generated
within the fuel pump, causing the fuel pressure to
become higher, thereby causing the fuel to be
expelled from the pump chamber and to pass
through the motor, opening the check valve, and to
be discharged from the discharge port.
Discharge port
4Check!nRelief valve
DC mo
-lllll1 I/
Circum-ferential
flow pumr
II’ f-Pump
casing
J
Pumpcovert
lntakler 03R0071REWEF VALVE
If for some reason, such as an abnormal condition at the
_discharge side, the fuel were not to be discharged, the fuel
pressure within the fuel pump would become abnormally high.
Thus, when the pressure within the fuel pump reaches
450-600 kPa (64-85 psi), the relief valve opens and the
pressure escapes, so that, the fuel line pressure does not
increase to the regulated level or above.
CHECK VALVE
When the pump stops, the check valve is closed by spring
force, so that there is high pressure remaining within the fuel
line.By in this way maintaining a high pressure within the fuel line,
the restarting of the engine becomes easier, and vapor-locks at
high temperature are prevented.
-
-_..I
-~

FUEL SYSTEM -Fuel Supply and Fuel Pressure Control14-9
03Poo4:Diaphragm
from intake
4Fuel from delivery pipe

4m
B(42.7)QQ
2
sl -196 2
(26.4) g
t
$!a d
9
0)Positive5 z‘. pressure
(E.2)
w
FUEL FILTERA high-pressure type filter is installed at the delivery end of the
fuel pump.
FUEL PRESSURE REGULATORThe fuel pressure regulator maintains the pressure of fuel
delivered to the injectors at a constant level of 335
kPa (47.6
psi) (Non-Turbo models) or 255
kPa (36.3 psi) (Turbo models)
higher than the manifold internal pressure, thus keeping the
volume of fuel injected constant regardless of changes in the
manifold pressure.
The spring chamber is connected by a vacuum hose with the
intake air plenum thus its interior pressure is always controlled
by the manifold vacuum.
The manifold vacuum created in the chamber functions to
decrease the spring pressure which forces down the valve
actuated by a diaphragm.
If this pressure forcing down the valve becomes less than the
fuel pressure, the diaphragm is forced up, allowing excess fuel
to flow back through the return pipe to the fuel tank.
Level “A” in the diagram to the left denotes the pressure
gauge reading when the vacuum hose is disconnected, in other
words, when the manifold vacuum is not applied to the spring
chamber.Level “B” denotes the pressure gauge reading when the
vacuum hose is connected: