1991 ACURA NSX air condition

General Info
Specifications
Maintenance
Engine
Cooling
Fuel and Emissions
’91’92 Models
’93’94 Models
’95’96 Models
*TransaxleSuspension
*Brakes (Including ABS)
*Body
*Heating, Ventilation and
Air Conditioning
*Body Electrical
*Engine Electrical
*SRS
1991-96 NSX Main Menu
As sections w/ * include SRS components,
special precautions are required when servicing.
Steering
’91’94 Models
’95’96 Models
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* 1 : Whe n usin g a ne w belt , adjus t deflectio n o r tensio n t o ne w values . Ru n th e engin e fo r 5 minute s the n tur n i t off .
Readjus t deflectio n o r tensio n t o use d bel t values .
*2 : D o no t adjus t th e gap , replac e spar k plu g i f i t i s ou t o f spec .
Electrica l - Sectio n 2 3
Air Conditionin g — Sectio n 2 2
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Air Conditionin g — Sectio n 2 2
Electrica l — Sectio n 2 3
*1 : Whe n usin g a ne w belt , adjus t deflectio n o r tensio n t o ne w values . Ru n th e engin e fo r 5 minute s the n tur n i t off .Readjus t deflectio n o r tensio n t o use d bel t values .*2: D o no t adjus t th e gap , replac e spar k plu g i f i t i s ou t o f spec .
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15. Loosen the idler pulley center nut and adjusting nut,

then remove the air conditioning (A/C) compressor
belt.

IDLER PULLEY
CENTER NUT

45 N·m
(4.5 kg-m,

33 lb-ft)

ADJUSTING

NUT

A/C COMPRESSOR

BELT

16. Remove the crankshaft pulley (see page 6-12 ('91-'93)
or ('94-'96)

17. Remove the rubber seal from the adjusting bolt,
then remove the middle covers and lower cover.

6 x 1.0 mm

12 N·m
(1.2 kg-m.

9 Ib-ft)
LOWER COVER RUBBER SEAL
6 x 1.0 mm
12 N·m
(1.2 kg-m,

9 lb-ft)

9 x
1.25
mm

22 N·m
(2.2 kg-m,

16 Ib ft)
IDLER PULLEY
ASSEMBLYCOLLAR
MIDDLE COVER
18. Loosen the adjusting boll 180
0
turn. Push the ten-

sioner to remove tension from the timing belt, then
re tighten the adjusting bolt.

ADJUSTING BOLT
Do not remove. When
adjusting, loosen

it
180°.

19. Remove the timing belt from the pulleys.ProCarManuals.com

24. Remove the engine wire harness connectors and
wire harness clamps from the cylinder head and
intake manifold, Six injector connectors
Intake air temperature (IAT) sensor connector
CKP/CYP sensor connector
Heated oxygen sensor (HO2S) connectors

Ignition control module (ICM) connectors

Engine coolant temperature (ECT) sensor connec-

tor

ECT gauge sending unit connector
ECT switch connector
Exhaust gas recirculation (EGR) valve lift sensor

connector

Throttle position sensor connector Engine oil pressure gauge sending unit connector
Knock sensor connector
VTEC solenoid valve connectors
VTEC pressure switch connectors
Engine oil pressure switch connector
Alternator connector

Alternator terminal

Throttle body 6P connector

25. Remove the ignition coils and connector.

26. Remove the EGR pipe and intake manifold assem- bly.

8 x 1.25mm

22 N·m (2.2 kg-m, 16 Ib-ft)

6 x 1.0 mm
12 N·m
(1.2 kg-m,

9 lb-ft)

GASKETS

Replace. INTAKE
MANIFOLD
ASSEMBLY

GASKET
Replace.
27. Loosen the adjusting nut and idler pulley center nut,
then remove the air conditioning compressor belt

(see page 6-17('91-'93) or ('94-'96)).

28. Remove the cover, adjusting bolt, mounting bolt and mounting nut, then remove the alternator belt
and alternator.

COVER

MOUNTING BOLT
10 x
1.25
mm

45 N·m (4.5 kg·m,

33 Ib-ft)

MOUNTING NUT
10 x
1.25
mm

45 N·m (4.5 kg·m.

33 Ib·ft)
ALTERNATOR

BELT

29. Disconnect the knock sensor connector, then remove
the wire holder.

6 x 1.0 mm
12N·m (1.2 kg-m, 9 Ib-ft)

KNOCK SENSOR
WIRE HOLDER
(cont'd)

6 x 1.0 mm

12 N·m (1.2 kg-m, 9 Ib-ft)

ADJUSTING

BOLTProCarManuals.com

Troubleshooting
How to Rea d Flowchart s
A flowchar t i s designe d to b e use d fro m star t t o fina l repair . It' s lik e a ma p showin g yo u th e shortes t distance . Bu t beware :
i f yo u g o of f th e "map " anywher e bu t a "stop " symbol , yo u ca n easil y ge t lost .
Describe s th e condition s o r situatio n to star t a troubleshootin g flowchart .
Ask s yo u to d o something ; perfor m a test , se t u p a conditio n etc .
Ask s yo u abou t th e resul t o f a n action , the n send s yo u in th e appropriat e troubleshootin g direction .
Th e en d o f a serie s o f action s an d decisions , describe s a fina l repai r actio n an d sometime s direct s yo u to
a n earlie r par t o f th e flowchar t t o confir m you r repair .
NOTE:
The ter m "Intermitten t Failure " i s use d in thes e charts . I t simpl y mean s a syste m ma y hav e ha d a failure , bu t i t check s
ou t O K a t thi s time . I f th e Malfunctio n Indicato r Lam p (MIL ) o n th e das h doe s no t com e on , chec k fo r poo r connection s
o r loos e wire s a t al l connector s relate d to th e circui t tha t yo u ar e troubleshootin g (se e illustratio n below) .
Mos t o f th e troubleshootin g flowchart s hav e yo u rese t th e Engin e Contro l Modul e (ECM ) an d tr y t o duplicat e th e
Diagnosti c Troubl e Cod e (DTC) . I f th e proble m is intermitten t an d yo u can' t duplicat e th e code , d o no t continu e throug h
th e flowchart . T o d o s o wil l onl y resul t i n confusio n and , possibly , a needlessl y replace d ECM .
"Open " an d "Short " ar e commo n electrica l terms . A n ope n i s a brea k i n a wir e o r a t a connection . A shor t i s a n acci -
denta l connectio n o f a wir e t o groun d o r t o anothe r wire . I n simpl e electronics , thi s usuall y mean s somethin g won' t
wor k a t all . I n comple x electronic s (lik e ECM's) , thi s ca n sometime s mea n somethin g works , bu t no t th e wa y it' s sup -
pose d to .
TIGH T
LOOS E
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Idle Contro l Syste m
Air Conditionin g Signa l
This signal s th e EC M whe n ther e is a deman d fo r coolin g fro m th e ai r conditionin g system .
Inspectio n o f Ai r Conditionin g
Signal .
ECM CONNECTOR S
Chec k fo r a shor t i n th e circuit :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e 12 P connecto rfrom th e coolin g fa n contro lunit.3. Tur n th e ignitio n switc h O N (II) .4. Measur e voltag e betwee n EC M
connecto r terminal s C 2 an d
A26 .WIR E SID E O F FEMAL E TERMINAL S
I s ther e approx . 1 0 V ? Chec
k fo r a shor t i n th e wire :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connec -tor C (12P ) fro m th e ECM .3. Chec k fo r continuit y betwee n
EC M connecto r termina l C 2
an d bod y ground .
I s ther e continuity ? —
Repai r shor t i n th e wir e
betwee n th e EC M (C2 ) an d th e
coolin g fa n contro l unit .
— Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
Substitut e a known-goo d EC M
an d recheck . I f prescribe d volt -
ag e i s no w available , replac e
th e origina l ECM .
Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
Chec k fo r a n ope n in th e circuit :
1. Tur n th e ignitio n switc h OFF .2. Reconnec t th e 12 P connecto r t o
th e coolin g fa n contro l unit .
3. Tur n th e ignitio n switc h O N (II) .4. Momentaril y connec t EC M
connecto r terminal s A 8 t o
A2 6 severa l time s wit h ajumpe r wire .
(To pag e 11-118 )
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Idle Contro l Syste m
Air Conditionin g Signa l
(From pag e 11-117 )
I s ther e a clickin g nois e fro m th e
A/ C compresso r clutch ?
Chec k fo r th e operatio n o f th e
A/C :1. Star t th e engine .
2 . Tur n th e blowe r switc h ON .
3 . Tur n th e A/ C switc h ON .
Doe s th e A/ C operate ?
Ai r conditionin g signa l i s OK . A/
C CLUTC H RELA Y 4P CONNECTO R
Chec k fo r a n ope n in th e wire :
Momentaril y connec t th e No . 4 ter -
mina l o f th e 4 P connecto r o n th e
A/ C clutc h rela y t o bod y groun d
severa l times .
WIRE SID E O F
FEMAL E TERMINAL S
I s ther e a clickin g nois e fro m th e
A/ C compresso r clutch ? Se
e ai r conditione r inspectio n (se e
sectio n 22 ).
Repai r ope n in th e wir e betwee n
th e EC M (AS ) an d th e A/ C clutc h
relay.
ECM CONNECTOR S
Chec k fo r a n ope n in th e wire :
Measur e voltag e betwee n EC M
connecto r terminal s C 2 an d A26 . WIR
E SID E O F FEMAL E TERMINAL S
I s voltag e les s tha n 1. 0 V ? Repai
r ope n in th e wir e betwee n
th e EC M (C2 ) an d th e A/ C switch .
Substitut e a known-goo d EC M
an d recheck . I f symptom/indi -
catio n goe s away , replac e th e
origina l ECM .
Se e th e ai r conditione r inspec -
tio n (se e sectio n 22 ).
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