sensor ACURA TL 1995 Service Owners Manual

14. Instal l th e revers e idle r gea r an d revers e idle r gea r
shaf t assembl y in th e transmissio n housin g (se e pag e
14-173 ).
15 . Assembl e th e mainshaf t sub-assembl y (se e pag e
14-150 ).
16 . Assembl e th e countershaf t sub-assembl y (se e pag e
14-153 ).
17 . Instal l th e secondar y drive n gea r shaf t i n th e torqu e
converte r housing .
18 . Instal l th e mainshaf t sub-assembl y an d th e counter -
shaf t sub-assembl y togethe r i n th e torqu e converte r
housing.
MAINSHAF TSUB-ASSEMBL YCOUNTERSHAF TSUB-ASSEMBLY
19. Instal l thre e dowe l pin s an d a ne w gaske t o n th e
torqu e converte r housing .
20 . Plac e th e transmissio n housin g o n th e torqu e con -
verte r housing .
CAUTION : Mak e sur e tha t th e mainshaf t an d coun -
tershaf t spee d sensor s ar e no t installe d o n th e
transmissio n housin g befor e installin g th e trans -
missio n housin g o n th e torqu e converte r housing .
21 . Instal l th e transmissio n housin g mountin g bolts , an d
torqu e the m in tw o o r mor e step s i n th e sequenc e
shown .
22 . Instal l th e 1 0 m m bol t an d thre e 8 m m bolt s t o th e
transmissio n housin g fro m th e torqu e converte r hous -
ing side , an d torqu e them .
23 . Instal l th e mainshaf t an d countershaf t spee d sensor s
o n th e transmissio n housing .
24 . Instal l th e connecto r bracket s an d connecto r holde r
o n th e transmissio n housing .
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Differential Assembl y
Removal (cont'd )
10. Remov e th e 3 3 m m sealin g bolt .
NOTE : Shif t th e transmissio n int o th e positio n
to loc k th e secondar y gear .
SECONDAR YGEAR
33 m mSEALIN G BOL T
11. Disconnec t th e extensio n shaf t fro m th e differentia l
usin g th e specia l too l a s shown .
EXTENSIO N SHAF T PULLE R07LAC-PW50101
SET RIN G
EXTENSIO N Replace .
SHAFT
12. Disconnec t th e oi l coole r hoses , breathe r tub e an d
VS S connector , the n remov e th e vehicl e spee d sen -
so r (VSS)/powe r steerin g spee d sensor .
NOTE:
• D o no t disconnec t th e hose s fro m th e powe r
steerin g spee d sensor .
• D o no t le t th e engin e coolan t flo w int o th e
differential .
VSS/POWE R STEERIN G
SPEE D SENSO R
VSSCONNECTO R
OILCOOLE RHOSES
BREATHE RTUBE
13. Remov e th e mountin g bolt s an d th e 2 6 m m shim .
MOUNTIN GBOLTS
MOUNTIN GBOLTS
26 m m SHI M
O-RIN G
Replace .
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Differential Assembl y
Installation (cont'd )
3. Instal l th e mountin g bolt s an d th e 2 6 m m shim .
Torque :12 x 1.2 5 mm64 N- m (6. 5 kgf-m , 4 7 Ibf-ft )
6 x 1. 0 m m12 N- m (1. 2 kgf-m ,8.7 Ibf-ft )
26 m m SHI M
4. Instal l th e vehicl e spee d senso r (VSS)/powe r steer -
in g spee d sensor , the n connec t th e oi l coole r hose s
an d th e breathe r tube .
VSS/POWE R STEERIN G
SPEE D SENSO R
VSS CONNECTO R
6 x 1. 0 m m12 N- m (1. 2 kgf-m ,8.7 Ibf-ft )
OILCOOLE RHOSES
BREATHE RTUBEO-RIN GReplace .
5. Instal l th e lef t fron t engin e moun t bracket .
12 x 1.2 5 mm74 N- m (7. 5 kgf-m ,54 Ibf-ft )
12 x 1.2 5 mm54 N- m (5. 5 kgf-m ,
4 0 Ibf-ft )
10 x 1.2 5 mm54 N- m (5. 5 kgf-m ,
4 0 Ibf-ft )
LEFT FRON T ENGIN E
MOUN T BRACKE T
6. Instal l th e splas h guard .
SPLAS HGUARD
6 x 1. 0 m m9.8 N- m (1. 0 kgf-m ,
7. 2 Ibf-ft )
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System Descriptio n
This powe r steerin g syste m is speed-sensitive . It s mai n component s ar e a mechanica l spee d sensor , a rotar y valve-typ e
gearbox, an d a constan t volume , vane-typ e pump . Th e syste m regulate s th e powe r assis t accordin g to vehicl e speed , roa d
conditions , an d drivin g style . Th e amoun t o f powe r assis t change s linearl y fro m hig h assist , whe n drivin g a t lo w speed s o r
parking , t o lo w assist , whe n drivin g a t hig h speeds .
Fluid Flo w Diagra m
The flui d volum e fro m th e pump , whic h i s drive n b y th e cran k pulley , i s regulate d b y th e flo w contro l valv e buil t int o th e
pump . Th e regulate d flui d i s fe d t o th e valv e bod y uni t locate d outsid e th e pinio n shaf t o f th e steerin g gearbox . Th e flui d i s
regulate d t o th e prope r pressur e b y th e valve s i n th e valv e bod y uni t an d b y th e powe r steerin g spee d senso r befor e it
flow s t o th e powe r cylinder . Th e directio n o f th e flo w is determine d b y th e rotar y valve . Th e flui d the n returns to th e reser -
voi r throug h th e retur n passag e an d i s fe d t o th e pum p again .
To RESERVOI R
VALVE BOD Y UNI T
TORSIO N BA R
INPU T SHAF T
VALVE (SLEEVE )
RIGHT CYLINDE R PASSAG E
POWE R CYLINDE R
Steering Gearbo xLOW SPEE D FEE D PASSAG E
The steerin g gearbo x i s th e rack-and-pinio n type . Th e valv e bod y uni t consist s o f th e valv e bod y unit , wher e th e flui d pas -
sag e i s regulate d b y th e flui d pressure , an d th e assis t contro l valv e uni t whic h regulate s th e flui d passag e t o th e rotar y
valv e accordin g t o vehicl e speed .
ASSIST CONTRO L VALV E UNI T
STEERIN G RAC K VALV
E BOD Y UNI T
ToRESERVOI R
From PUM P
POWE R CYLINDE RCYLINDE
R LINE S ASSIS
T CONTRO L VALV E UNI T
PUM P
To POWE R STEERIN G
SPEE D SENSO R
PUM
P OUTLE T
HIGH-PRESSUR E
HIGH SPEE D
FEE D PASSAG E
POWER STEERIN G
SPEE D SENSO R
RESERVOI R
LEFT CYLINDE R
PASSAG E
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One-way Valve (In Power Steering Speed

Sensor)

When the vehicle is moving at high speed, negative

pressure develops at the sensor inlet because the power

steering speed sensor is pumping faster than the fluid

can be supplied. To compensate for this, the outlet and

inlet ports are connected internally by a passage con-

taining a one-way valve that lets output fluid recirculate

to the inlet port to equalize pressure.

Driving at High Speed:

ONE-WAY VALVE
RESERVOIR

ROTORS
Relief Valve (In Power Steering Speed Sensor)

When the vehicle is moving in reverse, the power steer-

ing speed sensor also turns backward and pumps fluid

in the opposite direction. To avoid building up pressure

in the reaction chambers that would increase steering

effort while driving in reverse, the inlet and outlet-ports

are connected by a second internal passage containing a

relief valve that allows the fluid to recirculate.

Driving in Reverse:

RESERVOIR

RELIEF VALVEProCarManuals.com

System Descriptio n
System Operatio n
Assist Contro l Valv e
The assis t contro l valv e uni t consist s o f th e assis t contro l valve , whic h i s controlle d b y th e powe r steerin g spee d sensor ,
an d th e pressur e contro l valve . Th e pressur e contro l valv e an d th e assis t contro l valve , locate d betwee n th e pum p an d th e
spee d sensor , contro l th e flui d passag e t o th e rotar y valve . Th e flui d pressur e fro m th e pum p i s reduce d t o a "standar d
pressure " b y th e pressur e contro l valve , an d thi s standar d pressur e i s fe d t o th e assis t contro l valve . Th e standar d pres -
sur e i s draw n ou t b y th e rotatio n o f th e spee d sensor , producin g a pressur e ga p betwee n th e pressur e contro l valv e an d
th e assis t contro l valv e whe n th e standar d pressur e flui d passe s th e senso r orifice . Thi s pressur e gap , whic h change s wit h
th e flui d volum e draw n (tha t is , i t change s wit h vehicl e speed) , i s referre d t o a s th e powe r steerin g spee d senso r signa l
pressure . Th e assis t contro l valv e operate s accordin g t o thi s spee d senso r signa l pressur e t o chang e th e flui d passag e t o
th e hig h spee d rotar y valve .
POWE R STEERIN G SPEE D SENSO R
STANDAR D PRESSUR E
PRESSUR E CONTRO L VALV E
SPRING
To RESERVOI R
T o HIG H SPEE D VALV E
ASSIST CONTRO L VALV E POWE
R STEERIN G SPEE D
SENSO R SIGNA L PRESSUR E
ORIFICE
ORIFICE
FEED
SPRIN G
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System Description

System Operation (cont'd)

Hydraulic Control at Each Speed Range

When stopped:

When the vehicle is stopped with the engine idling, the fluid flow is shut off because the power steering speed sensor

rotor is not rotating. The standard pressure generated by the pressure control valve is applied to the assist control valve to

move the valve to the left. When the assist control valve is in this position, the orifice valve is closed. Therefore, the fluid

discharged from the pump is fed to the low speed valve of the valve body unit. Because the low speed valve has the small

chamfer and thereby the small opening angle, the large hydraulic pressure (steering rack thrust) results in the smallest

steering force (high assist).

HIGH SPEED FEED PASSAGE

LOW SPEED FEED PASSAGE
ASSIST CONTROL VALVE UNIT

POWER STEERING SPEED

SENSOR SIGNAL PRESSURE

HIGH SPEED

VALVE

SLEEVE

TORSION BAR

INPUT SHAFT

VALVE BODY UNIT

SENSOR ORIFICE

ASSIST VOLUME: LIGHT

STEERING WITH VEHICLE PARKED

ROAD SURFACE RESISTANCE

SMALL
LARGE
FLOW: O (ZERO)

LOW SPEED

VALVE

POWER STEERING SPEED

SENSOR AT A STOP
RESERVOIR
PUMP
FULL CLOSE

PRESSURE CONTROL VALVE
(HIGH)
ASSIST CONTROL

VALVEProCarManuals.com

Middle speed range:

When the vehicle starts to move, the power steering speed sensor rotor starts to rotate as well, reducing the standard

pressure and generating the power steering speed sensor signal pressure. The valve returns to the right point where the

pressure of the power steering speed sensor signal equals the spring force of the assist control valve. When the assist

control valve is in this position, the orifice of the valve slightly opens.

Therefore, the fluid pressure from the pump is applied to the high speed valve of the valve body unit. Because the high

speed valve has a larger chamfer and the compound opening area with the low speed valve is larger than that when the

vehicle is stopped, the fluid pressure (steering rack thrust) is not generated unless the displacement angle is large (large

steering torque), resulting in moderately heavy steering (medium assist).

FLOW: MIDDLE
ASSIST CONTROL VALVE UNIT

POWER STEERING SPEED

SENSOR SIGNAL PRESSURE (MEDIUM)

MIDDLE POWER STEERING SPEED

SENSOR ROTATION SPEED

MODERATELY HEAVY STEERING

IN MIDDLE SPEED RANGE
SMALL
ROAD SURFACE

RESISTANCE LARGE

High speed range:

When the vehicle is driven at high speed, the power steering speed sensor rotor rotates at a high speed, greatly reducing

the standard pressure. The pressure of the power steering speed sensor signal is at the lowest value, and the assist con-

trol valve is at the right end position.

When the assist control valve is in this position, the orifice of the valve opens fully. Therefore, the fluid pressure applied to

the high speed valve is larger than when the engine speed is at the middle speed range. The compound opening area with

the low speed valve is the largest this time, and the fluid pressure (steering rack thrust) is not generated unless the dis-

placement angle is very large (low assist).

FLOW: LARGE
ASSIST CONTROL VALVE UNIT

POWER STEERING SPEED

SENSOR SIGNAL PRESSURE (LOW)

HIGH POWER STEERING SPEED

SENSOR ROTATION SPEED

LOW ASSIST: ADEQUATELY HEAVY

STEERING IN HIGH SPEED RANGE
SMALL
-ROAD SURFACE

RESISTANCE LARGE
PRESSURE CONTROL VALVE

SENSOR ORIFICE
HALF OPEN
ASSIST CONTROL

VALVE

VALVE BODY UNIT

ASSIST CONTROL

VALVE

FULL OPEN

SENSOR ORIFICE
PRESSURE CONTROL VALVEProCarManuals.com

From pag e 17-1 2
Chec k forc e require d t o tur n th e
whee l (se e pag e 17-20 ).
Star t th e engin e an d measur e
force require d t o tur n th e whee lto th e righ t an d left . Differenc e o fth e forc e require d t o tur n th ewhee l t o th e righ t an d t o th e lef tshoul d b e 2. 9 N (0. 3 kgf , 0. 7 Ibf )
o r below . Abnorma
l
Check cylinde r pipe s A an d B fo r deformation .
Norma l No
t deforme d
Faulty valv e bod y uni t
Deforme d
Faulty cylinde r pip e
Measur e th e forc e require d t o
tur n th e whee l wit h th e powe r
steerin g spee d senso r hos e
plugge d an d th e vehicl e parke d(see pag e 17-20 ).
Abnorma l
Steering effor t belo w 2 4 N (2. 4 kgf , 5. 3 Ibf) . Connec t
th e senso r hos e a s it is .
I f th e steerin g effor t i s abov e 2 4 N (2. 4 kgf , 5. 3 Ibf) ,
replac e th e powe r steerin g spee d sensor .
Steerin g effor t abov e 2 4 N (2. 4 kgf , 5. 3 Ibf) . Chec k
th e assis t contro l valv e fo r stickin g o r a clogge d ori -
fice ; clea n th e valv e a s necessar y (se e pag e 17-55 ).
Assis t contro l valv e is norma l
Chec k th e gearbox .
Remov e th e gearbo x an d mea -
sur e th e pinio n torque .
Th e torqu e shoul d be ;
* 0. 6 - 1. 2 N- m (6 - 1 2 kgf-cm , 5. 2
- 1 0 Ibf-in ) wit h th e steerin g rac k
i n th e straigh t drivin g position .
* 1. 3 N- m (1 3 kgf-cm , 11. 3 Ibf-in )with th e steerin g rac k i n an y
othe r position .
Normal
Check th e part s othe r tha n th e gearbox-relate d part s fo r
prope r rotation .
• Imprope r rotatio n o f th e steerin g column-relate d part(s )
• Fault y steerin g join t
• Fault y rac k end/tie-ro d en d bal l joint s
• Interferenc e in th e steerin g syste m
Abnorma l
Adjus t th e rac k guid e (se e pag e
17-24 ), an d rechec k th e pinio n
torque.
Norma l Improperl y adjuste d rac k guid e
Abnorma l
Faulty gearbo x
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Troubleshooting
General Troubleshootin g (cont'd )
Assist (excessivel y ligh t steering ) a thig h speed . Chec
k th e rac k guid e fo r prope r
adjustmen t (se e pag e 17-24 ).
Measur e forc e require d t o tur n
whee l wit h bypas s tub e join tinstalled , an d th e vehicl e parke d o n
dr y pave d surfac e (se e pag e 17-21 ). I
f th e proble m is no t correcte d b y
adjustin g th e rac k guide , adjus tthe fron t whee l alignmen t (se e
sectio n 18 ).
I f belo w th e specifications , chec k
th e powe r steerin g spee d sensor ,
assis t contro l valve , pressur e
contro l valv e an d valv e bod y uni t
fo r stickin g o r a clogge d orifice .
Shoc k o r vibratio n whe n whee l i s
turne d t o ful l lock . Chec
k th e rac k guid e fo r prope r
adjustmen t (se e pag e 17-24 ).
Rac k guid e is adjuste d properly .
Chec k th e bel t fo r slippag e an d
adjus t a s necessar y (se e pag e
17-23 ).
Rac k guid e wa s backe d of f exces -sively.
Adjus t th e rac k guide .
I f th e proble m is no t correcte d b y
adjustin g th e rac k guide , replac e
th e gearbox .
Steering whee l wil l no t retur nsmoothly . Chec
k cylinde r line s A an d B fo r
deformation .
A an d B cylinde r line s ar e nor -mal, chec k whee l alignmen t (se e
sectio n 18 ).
Whee l alignmen t i s normal .
Remov e th e gearbo x fro m th e
fram e an d measur e th e pinio n
torqu e o n th e gearbox . A
o r B cylinde r lin e i s deformed ;
replac e it .
Whee l alignmen t i s abnormal ,
adjus t a s needed .
I t shoul d b e 0. 7 - 1. 2 N- m (7 -
1 2 kgf-cm , 6-1 0 Ibf-in ) o r les s
wit h th e steerin g rac k i n th e
straigh t ahea d drivin g position .
1. 3 N- m (1 3 kgf-cm , 11. 3 Ibf-in )
wit h th e steerin g rac k i n an y
othe r position .
I f th e measurement s ar e ou t o f
specifications , adjus t th e rac k
guide .
I f th e proble m is no t correcte d b y
adjustin g th e rac k guide , replac ethe gearbox .
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