low oil pressure MITSUBISHI ECLIPSE 1990 Owner's Manual

FUEL SYSTEM -Idle Speed Control14-51
_ 0 (32)80 (175)Coolant temperature “C (“F)6FUO2653
ATarget position during operation
of the power steering systemIDLE CONTROL SERVO POSITION CONTROL WHEN THE
ENGINE IS IDLING
(1) Basic position
The basic position is preset as a map value Optimized
according to the engine coolant temperature. The idle
speed control servo is activated to conform to this position,
thereby maintaining the optimum idle speed.
This basic position of the idle control servo
diiectlycorresponds to the basic idle speed described earlier.
1II
0(32)
80(176)Coolant temperature
“C VW6FUO291Servo position
during operation of
the air conditioner
0(32)
80(176)Coolant temperature “C (“F)6FUO757
1L)760 (30)Barometric pressure mmHg
(in.Hg)BFUlOlC(2) Servo position during shift to “D” range
For models equipped with the automatic
transaxle.when
the position of the shift lever is anywhere other than the
“P” or “N” range, the servo position is increased in
proportion to the load of the torque-converter.
(3) Idle control servo position during operation of the power
steering system
When the power steering oil pressure switch is turned on
because the steering wheel is being turned while
thevehicle is stationary, the servo position is changed to
correspond to the increased power steering pump load.
(4) Servo position while the air conditioner is being operated
When the air conditioner switch is turned on, the servo
position is changed to correspond to the increased air
conditioner load.
(5) High altitude compensation
A correction is performed by increasing the opening of the
idle speed control servo to allow increasing bypass air flow
in order to compensate for the loss of intake air volume
(asmeasured by weight) caused by a reduction in intake air
density due to a drop in barometric pressure at increased
altitude.
(6) “Training” function
A “training” function that enters a value based upon the
engine rpm and the target rpm into the memon/,
andcorrects the servo position according to this value, is
provided in order to obtain an even higher degree of
precision of position control.

:POWER STEERING
- Pinion and Valve Assembly Construction19-7 ’fOPERATION OF THE PINION AND VALVE
fi %EMBLYdulation of the hydraulic pressure applied to the
power cylinder is performed by the input shaft and
the rotary valve.
The concave and convex parts at the input shaft
surface and the rotary valve inner surface, due to
the rotational difference, function to either constrict
or expand the fluid passageway (by varying the
aperture surface area of the fluid passageway), and,
as a result, thereby regulating the hydraulic pressure
of the hydraulic circuit from the oil pump to the
cylinder tube left chamber or right chamber and
from the cylinder tube right chamber or left chamber
to the oil reservoir.
WHEN THE STEERING WHEEL IS TURNED TOTHE
RIGHTWhen the steering wheel is turned to the right, the
Port b\
Port a\Pond’
Ltorsion bar is. as shown in the illustration, caused to
torque in the direction of turning to the right, with
the result that the input shaft rotates by the
corresponding amount to the right, and a rotational
difference between the input shaft and rotary valve
develops. The concave and convex parts of the
input shaft and rotary valve cause oil passageways
R’ and L to become constricted, with the result that,
for the fluid sent from the oil pump, the flow of fluid
is stopped from port “a” to port “d” and port “c”.
When this happens, the fluid flows from the oil
pump to sleeve “a”,port “a”, port “b” and sleeve
‘lb”, and is sent to the cylinder tube right chamber,
thus causing the generation of a force to move the
rack in the leftward direction, thereby assisting the
steering effort of the steering wheel. At the same
time, the cylinder tube left chamber fluid flows
through sleeve “c”, port “c”, port “d” and chamber
“A”, and is returned to the oil reservoir.
Port c
Oil pumpOil ryetvoir
From the leftcylinder tubeChamber “A”
Torsion bar Port
b
//II YPO< aPond
4Cylinder tube
left chamberCylinder tube
right chamber

19-8POWER STEERING -Pinion and Valve Assembly Construction
WHEN THE STEERING IS AT THE CENTER POSI-
TIONBecause the input shaft does not rotate, the
and chamber “A”,returning to the oil reservoir.
position is the center (neutral) position relative to
Note that the power assist is not activated, because
the rotary valve, and the fluid supplied from the oil
no pressure difference develops in the left and right
pump flows through sleeve “a”, port “a”, port “d”
cylinder tube chambers.
Fromoil pumpVTo the left
cylinder tubeOil pump
Oil reservoir
/
13L0072Chamber “A”
JI& chamberright chamber

POWER STEERING - Oil Pump13A0067
Insi
OIL PUMPRlUAM
The oil pump has a separate oil reservoir; it is a vane-type pumpthat generates hydraulic pressure by the rotor, vanes and cam
y”ht oil pump incorporates a flow-control valve (in order to
reduce the power-assist effect during high-speed driving and
thereby improve steering stability) and a relief valve (in order to
maintain the hydraulic pressure and steering linkage rela-
tionship).
NOTEThe relief valve is incorporated within the flow-control valve.
OPERATION OF THE OIL PUMP
The rotation of the rotor causes the ten vanes to move radially
by centrifugal force, and when there is rotation along the cam
curved surface of the circular cam ring, there is action in the
radial direction along the cam curved surface.
The fluid chamber is formed by the cam ring, rotor and vanes;
when the rotor rotates the inner surface of the cam ring
(circular), the fluid chamber pressure changes to negative
pressure, with the result that the fluid within the oil reservoir,
which is at atmospheric pressure, is drawn in (suction step),
after which the rotor rotates further, discharging the fluid
(discharge step).
The action of this pump is two intake strokes and
two
discharge strokes for each vane during one rotation of the rotor.

POWER STEERING - Oil Pump
OIL PUMP13A0067
Insi
m-
The oil pump has a separate oil reservoir; it is a vane-type pumpthat generates hydraulic pressure by the rotor, vanes and cam
;Inhz oil pump incorporates a flow-control valve (in order to
reduce the power-assist effect during high-speed driving and
thereby improve steering stability) and a relief valve (in order to
maintain the hydraulic pressure and steering linkage rela-
tionship).
NOTEThe relief valve is incorporated within the flow-control valve.
.OPERATION OF THE OIL PUMP
The rotation of the rotor causes the ten vanes to move radially
by centrifugal force, and when there is rotation along the cam
curved surface of the circular cam ring, there is action in the
radial direction along the cam curved surface.
The fluid chamber is formed by the cam ring, rotor and vanes;
when the rotor rotates the inner surface of the cam ring
(circular), the fluid chamber pressure changes to negative
pressure, with the result that the fluid within the oil reservoir,
which is at atmospheric pressure, is drawn in (suction step),
after which the rotor rotates further, discharging the fluid
(discharge step).
The action of this pump is two intake strokes and two
discharge strokes for each vane during one rotation of the rotor.

POWER STEERING - Oil Pump
PERFORMANCE OF THE OIL PUMP
(1)
19-11 i
P-Qf characteristic (pump pressure vs. discharge quantity)
At pump rotation of 600 rpm and fluid temperature of
50-6O”C (122-l 40°F):4.4
litmin. (268.5 cu.in./min.), or more at pump pressure of
4,000
kPa (569 psi)
N-Qf Characteristic (pump rpm vs. discharge quantity)
At pump pressureof 2,000
kPa (285 psi) and fluid
temperature of
50-60X (122-140°F):
6.58
lit./min. (396.7-488.2 cu.in./min.) at pump rotation of
1,500 rpm.
3.8-6 lit./min. (231.9-366.1 cu.in./min.) at pump rotation of
3,000 rpm.
2.5-3.5 Mnin. (152.6-213.6 cu.in./min.) at pump rotation
of 4,500 rpm.
OPERATION OF THE FLUID
FLOW-
r7NTROL SYSTEM
I t 13 plunger and flow-control valve are activated bythe oil pump, thus regulating the amount of fluid
the hydraulic pressure of the fluid discharged fromflow to the gear box.
Pl;lgRelief ipring\
Relief valve13POO37

19-12POWER STEERING - Oil Pump
WHEN OIL PUMP OPERATES AT LOW SPEED
(70&l ,000 RPM)
A part of the fluid discharged from the oil pumpvariable orifices. As a result of this action the fluid
passes through the pilot port and hydraulic pressurepasses through the variable and fixed orifices, and is
is applied to the rear surface of the plunger, but,sent, by way of the plunger, to the gear box. The
because this hydraulic pressure is weak, the plungeramount of discharge to the gear box at this time is
is pushed toward the left as a result of the forcealmost maximum, with the result that an extremely
applied by the plunger’s spring, thus opening thelow steering effort is required.
PlungerVariable orificeFixed,orificeFioycontrol valve
/ I
From oil pump
To oil pumpVariable orifice
13POO38-.
Pilot portFixed orifice
.WHEN OIL PUMP OPERATES AT MEDIUM
SPEED
(1 ,OOm,OOO RPM)
When the engine speed increases and the pump’ssame time, the flow-control valve also is pressed
speed also increases, the hydraulic pressure of thetoward the
right, the bypass port opens more, and
fluid discharged from the pump becomes higher,the surplus fluid is returned back to the oil pump. In
overcoming the plunger spring’s force, and causingthis way, the amount of discharge flow to the gear
the plunger to move toward the right. As a result ofbox is reduced, thus resulting in a somewhat
this action, one of the variable orifices closes. At the“heavier” steering effort.
Variable orifice
PlungerFlow-control valve
\\Fixed yrifice/
Variable &iflceBypass ‘LrllJPOO59

i t-7POWER STEERING
- Oil Pump19-13WHEN OIL PUMP OPERATES AT HIGH SPEED
(? -70 RPM OR MORE)
VII, ,dn the pump operation becomes high speed. thethe gear box then is supplied only from the fixed
plunger is pushed further toward the
right than fororifice, with the result that the amount of discharge
medium speed, and both variable orifices close.flow
is reduced to minimum, and, as a result, theFurthermore. the flow-control valve also moves, and
steering effort becomes moderately “heavy”, thus
the bypass port opens wider. The fluid flowing to
providing excellent handling stability at high speed.
Fixed orifice13POO40
OPERATION OF THE RELIEF VALVE
When the A chamber pressure increases when theAs a result of this action, the pressure of the
Bsteering wheel is turned while the vehicle ischamber decreases, and the relief valve closes once
stopped, the
B chamber pressure also increases.again. This action takes place in a moment, and in
and, when the pressure exceeds the relief springthis way, by maintaining the correct balance, the
set load of 8,000 kPa (1,138 psi), the relief valve panmaximum pressure is controlled.
which is closed by a steel ball opens and the fluid
passes through the bypass port and is returned to
the pump’s intake port.
Steel ballRelief sprtngTo steering gear box
/Bypass pan
WPOO41

_-
21-16AUTOMATIC TRANSAXLE - General InformationAUTOMATIC
TRANSAXLE
GENERAL INFQRMATIONRzlBBACF4A22 automatic transaxles with different shift pattern are introduced to match engine output characteristics.
These F4A22 automatic transaxles are transaxles of KM1 70 Type II series and each is a two-mode
electronically controlled automatic transaxle with shift patterns of two modes.
SPECIFICATIONS
Items
Transaxle modelTorque convertor
Me
Stall torque ratio
TransaxleType
Gear ratio
1 St
2nd
3rd4th
ReversePrimary reduction ratio
Differential gear ratio
Friction elements
Number of front clutch discs
Number of rear clutch discs
Number of end clutch discs
Number of low/reverse brake discs
Number of
kickdown brake bandControl system
Manual control system
Shift pattern type
Solenoid yalve operationShift control
(2)
Pressure control
Damper clutch controlDiagnosis
Indication method
Number of diagnosis items
Speedometer gear ratio
ATFOil quantityliter
(qts.)
Specifications-4A22-2-MPAl3element, 1 -stage,
2-phase with damper clutch
2.17l-speed forward, l-speed reverse
2.846
1.581
1
.ooo
3.685
2.176
1.125
3.611V&N-D-2-L (lever type) with overdrive switch
Two-mode electronic-hydraulic control type
ON-OFF controlDuty control
Duty control
Indication with
LEDs
24
29136
MOPAR ATF PLUS (AUTOMATIC TRANSMISSIOI
FLUID TYPE 7176VAutomatic Transmission Fluid“DEXRON” or “DEXRON II”
\I6.1
(6.4)J

AUTOMATIC TRANSAXLE - Torque Converter
TORQUE CONVERTER
Lock
ring
I
Damper
F
clutch-
B-.Turbine
.AA
/:ront cover
h,Impeller
AStartorWhen damper clutch is
I\When damper
aInput shaftactivated
clutch isactivated
175202The torque-converter is composed of the impeller
(rear cover), turbine,
stator, damper clutch, one-way
clutch, front cover, etc.Furthermore. the torque-converter cannot be dis-
assembled because the outer circumference of the
shell
(front cover and rear cover) is sealed by
welding.
Because the torque-converter is coupled to the
engine’s crankshaft (via the drive plate). the shell
(front cover and impeller) always turns in the same
way when the engine is running.
As a result, the oil pump is also caused to rotate (by
the hub welded to the center part of the rear of the
shell) at the same speed as the engine.
The boss at the front part of the shell is inserted in
the hole at the rear part of the crankshaft. thus
providing support of the torque-converter.
A facing like that attached to the transaxle’s clutch
disc is attached to the damper clutch, and the
damper clutch and the turbine are connected by the
tabs (of the lock ring on the outer circumference of
the turbine shell) that fit into the groove on the outer
circumference of the damper clutch.
The torque-converter actuation hydraulic pressure,at the damper clutch activation area, passes be-
tween the torque-converter’s hub and the reaction
shaft, and enters the torque-converter.
When this happens, the hydraulic pressure acts
upon the A part (between the damper clutch and the
turbine), with the result that the damper clutch is
pressed against the front cover, and the damper
clutch, with a slight slip (as described later) becom-
es connected.
In this manner, the amount of slippage of the
torque-convener is reduced, without a damper
spring, to far below at even the low-speed level,
thus making a practical improvement of fuel con-
sumption.
At the damper clutch non-activation area, because
the torque-converter actuation hydraulic pressure
passes through the input shaft oil passage
-1enters the torque-converter from the
B part &-tween the damper clutch and the front cover). the
damper clutch moves away from the front
cover,thus releasing the damper clutch.
In this condition, operation is as an ordinary torque-
converter.