1995 ACURA TL Service Repair Manual

THROTTLE LEVE R
There shoul d b e
n o clearance .
THROTTL E STO P SCRE W
(D o no t adjust. )
Replace th e throttl e bod y if ther e is excessiv e pla y i n th e throttl e valv e shaf t o r i f th e shaf t i s bindin g o r sticking .
Remova l
GASKETReplace .
22 N- m(2.2 kgf-m , 1 6 Ibf-ft )
NOTE :
• Th e throttl e sto p scre w in non-adjustable .
• Afte r reassembly , adjus t th e throttl e cabl e (se e pag e 11-137 ).
THROTTL E CABL E
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Intake Air System

Throttle Body (cont'd)

Disassembly

IDLE ADJUSTING

SCREW

O-RING

TP

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Intake Air Bypass (IAB) Control System

Description

Two air intake paths are provided in the intake manifold to allow the selection of the intake path most favorable for a

given engine speed. Satisfactory power performance is achieved by closing and opening the intake Air Bypass (IAB)

valves. High torque at low rpm is achieved when the IAB valves are closed, whereas high power at high rpm is achieved

when the IAB valves are opened.

IAB CONTROL

DIAPHRAGM

From No. 4 ECU (ECM)

('95-96 models: 15A,

'97 - 98 models: 20A) FUSE

(In the under-dash

fuse/relay box)

VARIOUS

SENSORS

IAB

CONTROL

SOLENOID

VALVE

IAB VACUUM TANK

IAB CONTROL SOLENOID VALVE OFF

ENGINE RPM IS ABOVE 4,800 rpmProCarManuals.com

Intake Ai r Syste m
Intake Ai r Bypas s (IAB ) Contro l Syste m (cont'd )
Troubleshootin g
Is ther e vacuum ?
IABCONTRO L DIAPHRAG M
VACUUMPUMP/GAUGE , 0-3 0 in.H g
A973 X - 04 1 - XXXX X
Chec k fo r vacuu m at IA B vacuu m
tank :
Remov e No . 1 3 vacuu m hos e fro m
th e IA B vacuu m tank , the n chec k
fo r vacuu m a t th e IA B vacuu m
tank .
Is ther e vacuum ? Repai
r th e blockag e o r vacuu m
lea k betwee n th e IA B vacuu m
tan k an d th e intak e manifold .
Chec k fo r a n ope n i n th e wir e
(IA B SO L line) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e IA B contro l
solenoi d valv e connector .
3 . Tur n th e ignitio n switc h O N (II) .
4 . Measur e voltag e betwee n th e
IA B contro l solenoi d valv e 2 P
connecto r terminal s No . 1 an d
No. 2 .
IA B CONTRO L SOLENOI D
VALV E CONNECTO R (C110 )
Wir e sid e o f femal e terminal s
I s ther e batter y voltage ? Replac
e th e IA B contro l solenoi d
valve.
Check fo r a n ope n in th e wir e (IG 1line) :Measur e voltag e betwee n bod ygroun d an d th e IA B contro lsolenoid valv e 2 P connecto r termi -nal No . 2 .
(T o pag e 11-143 ) (T
o pag e 11-143 )
Inspectio n o f IA B Contro l System .
Check fo r vacuu m at idle :
1 . Star t th e engin e an d allo w i t
to idle .2. Remov e th e vacuu m hos e fro m
th e IA B contro l diaphrag m an d
connec t vacuu m gaug e t o th e
hose .
No. 1 3 VACUU M
HOSE
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(From pag e 11-142 ) (From pag e 11-142 )
I s ther e batter y voltage ? Repai
r ope n i n th e wir e betwee n
th e IA B contro l solenoi d valv e con -
necto r an d No . 4 EC U (ECM ) ('95 -96 models : 1 5 A , '9 7 - 9 8 models :
2 0 A ) fus e i n th e under-das h
fuse/rela y box .
Chec k fo r a n ope n in th e wir e (IA B
SO L line) :
Connec t EC M connecto r terminal s
A9 an d A2 6 wit h a jumpe r wire .
Doe s th e solenoi d valv e clic k
whe n th e jumpe r i s connected ?
Substitute a known-goo d EC M an drecheck . I f symptom/indicatio ngoes away , replac e th e origina lECM.
Is ther e vacuum ?
Chec k fo r a shor t i n th e wir e (IA B
SO L line) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connecto rA (26P) .3. Chec k fo r continuit y betwee n
bod y groun d an d th e IA B con -
tro l solenoi d valv e 2 P connec -
to r termina l No . 1 .
I s ther e continuity ?
NO
Substitut e a known-goo d EC Mand recheck . I f sympto m goe saway, replac e th e origina l ECM .
Repai r ope n i n th e wir e betwee nECM (A9 ) an d th e IA B contro lsolenoid valv e connector .
Replac e th e IA B contro l solenoi d
valve.
Wire sid e o f femal e terminal s
Repai r shor t t o groun d a t th e wir e
betwee n EC M (A9 ) an d th e IA Bcontro l solenoi d valv e connector .
11-143
Check fo r vacuu m a t 5,00 0 rpm :
1 . Rais e engin e spee d t o abov e
5,00 0 rpm .
2 . Chec k fo r vacuu m a t th e vacu -
u m hose .
I s ther e vacuum ? Disconnec
t th e IA B contro l solenoi d
valv e connector .
IAB contro l syste m is OK .
ECM CONNECTO R A (26P )
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Intake Ai r Syste m Emissio
n Contro l Syste m
Intake Ai r Bypas s (IAB ) Contro l
Syste m (cont'd )
Intake Ai r Bypas s (IAB ) Contro l Valv e Testin g
1. Chec k th e IA B contro l valv e shaf t fo r bindin g o r stick -
ing.
2. Chec k th e IA B contro l valv e fo r smoot h movement .
3. Chec k tha t o f th e IA B contro l valv e is i n clos e con -
tac t wit h th e stoppe r whe n th e vacuu m hos e i s dis -
connecte d fro m th e IA B contro l diaphragm .
IAB CONTRO L VALV ESTOPPE R
4.Chec k tha t o f th e IA B contro l valv e is in clos e con -
tac t wit h th e full-clos e scre w whe n yo u appl y 5 1 kP a
(38 0 mmHg , 1 5 inHg ) o f vacuu m to th e IA B contro l
diaphragm .
FULL-CLOS ESCREW(Do no t adjust. )
If an y faul t i s found , clea n th e linkag e an d shaft s wit h
carbureto r cleaner . I f th e proble m stil l exist s afte r clean -
ing , disassembl e th e intak e manifol d an d chec k th e IA B
valv e bod y assembl y (se e sectio n 9 ).
Syste m Descriptio n
The emissio n contro l syste m include s a War m U p Thre e
Wa y Catalyti c Converte r (W U TWC) , a Thre e Wa y Catalyti c
Converte r (TWC) , Exhaus t Ga s Recirculatio n (EGR ) system ,
Positiv e Crankcas e Ventilatio n (PCV ) syste m an d
Evaporativ e Emissio n (EVAP ) Contro l system . Th e emis -
sio n contro l syste m is designe d t o mee t federa l an d stat e
emissio n standards .
Tailpipe Emissio n
Inspectio n
Do no t smok e durin g thi s procedure . Kee p
an y ope n flam e awa y fro m you r wor k area .
1 . Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
no loa d (transmissio n i n o r position ) unti l th e
radiato r fa n come s on , the n le t i t idle .
2 . Connec t a tachometer .
3 . Chec k an d adjus t th e idl e speed , i f necessar y (se e
pag e 11-117 ).
4 . War m u p an d calibrat e th e C O mete r accordin g to th e
mete r manufacturer' s instructions .
5 . Chec k idl e C O wit h th e headlights , heate r blower ,
rea r windo w defogger , coolin g fan , an d ai r condition -
er off .
NOTE : (Canada ) Pul l th e parkin g brak e leve r up .
Star t th e engine , the n chec k tha t th e headlight s ar e
off.
CO mete r shoul d indicat e 0.1 % maximum .
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Three Way Catalytic Converter (TWC)

Description

The Three Way Catalytic Converter (TWC) and Warm Up Three Way Catalytic Converter (WU TWC) are used to convert

hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO2), dini-

trogen (N2) and water vapor.

PRIMARY

HEATED

OXYGEN SENSOR

(PRIMARY HO2S)
HOUSING

WARM UP

THREE WAY

CATALYST

THREE WAY

CATALYSTS

SECONDARY

HEATED

OXYGEN SENSOR

(SECONDARY

HO2S)

FRONT OF

VEHICLE
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Exhaust Ga s Recirculatio n (EGR ) Syste m
Descriptio n
The EG R syste m is designe d to reduc e oxide s o f nitroge n emission s (NOx ) b y recirculatin g exhaus t ga s throug h th e EG R
valv e an d th e intak e manifol d int o th e combustio n chambers . I t i s compose d o f th e EG R valve , EG R vacuu m contro l valve ,
EG R contro l solenoi d valve , EC M an d variou s sensors .
Th e EC M contain s memorie s fo r idea l EG R valv e lift s fo r varyin g operatin g conditions . Th e EG R valv e lif t senso r detect s
th e amoun t o f EG R valv e lif t an d send s th e informatio n t o th e ECM . Th e EC M the n compare s it wit h th e idea l EG R valv e lif t
whic h i s determine d b y signal s sen t fro m th e othe r sensors . I f ther e i s an y differenc e betwee n th e two , th e EC M cut s cur -
ren t t o th e EG R contro l solenoi d valv e to reduc e vacuu m applie d to th e EG R valve .
EGRVACUU MCONTRO LVALVE
EGRCONTRO L
SOLENOI D
VALVE
EGR VALV E
LIF T SENSO R Fro
m No . 4 EC U (ECM )
('9 5 - 9 6 models : 15A , '9 7 - 9 8 models : 20A )
FUS E
(i n th e under-das h fuse/rela y box )
VARIOU S
SENSOR S
EG R VALV E
INTAKE
MANIFOL D
ECM
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