1991 ACURA NSX Service Repair Manual

Thermostat
Replacemen t
NOTE: Us e ne w gasket s an d O-ring s whe n reassem -
bling.
ENGIN E COOLAN T
TEMPERATUR E (ECT ) GAUG E
SENDIN G UNI T
9 N- m (0. 9 kg-m , 7 Ib-ft )
Apply liqui d gaske tto th e threads .
WATE R PASSAG E
8 x 1.2 5 mm22 N- m (2. 2 kg-m ,16 Ib-ft )BLEE D BOL T
1 0 N- m (1. 0 kg-m , 7 Ib-ft )
6 x 1. 0 m m12 N- m (1. 2 kg-m ,9 Ib-ft )
ECT SWITC H18 N- m (1. 8 kg-m ,13 Ib-ft )
8 x 1.2 5 mm22 N- m (2. 2 kg-m , 1 6 Ib-ft )
THERM O COVE R
O-RING Replace .
Testing
Replac e thermosta t i f i t i s ope n a t roo m temperature .
T o tes t a close d thermostat :
1 . Suspen d th e thermosta t i n a containe r o f wate r a s
shown .
2. Hea t th e water , an d chec k th e temperatur e wit h a
thermometer . Chec k th e temperatur e a t whic h th e
thermosta t firs t open s an d a t ful l lift .
CAUTION : D o no t le t thermomete r touc h th e botto m
o f th e ho t container .
3 . Measur e lif t heigh t o f th e thermosta t whe n full y open .
STANDAR D THERMOSTA T
Lif t height : abov e 1 0 m m (0.3 9 in )
Start s opening : 169-176° F (76-80°C )
Fully open : 194° F (90°C )
THERMOMETE R
THERMOSTA T
THERMOSTA
T
Install wit h pi n up .
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Water Pum p
Illustrate d Inde x
NOTE : Us e ne w O-ring s an d ne w specia l bolt s whe n
reassembling .
8 x 1.2 5 mm22 N- m (2. 2 kg- m16 Ib-ft )
ECT SWITC H18 N- m (1. 8 kg-m ,13 Ib-ft ) ENGIN
E COOLAN T
TEMPERATUR E (ECT )GAUG E SENDIN G UNI T9 N- m (0. 9 kg-m ,7 Ib-ft )Apply liqui d gaske tto th e threads .BLEED BOL T10 N- m(1.0 kg-m , 7 Ib-ft )
8 x 1.2 5 mm22 N- m (2. 2 kg-m ,16 Ib-ft )
O-RIN G
Replace .
DRAIN BOLT S
1 0 N- m (1. 0 kg-m , 7 Ib-ft )
Us e rubbe r hose s
when draining .
SPECIAL BOL T
8 x 1.2 5 mm : 2 BOLT S
2 2 N- m (2. 2 kg-m , 1 6 Ib-ft )
Replace . DOWE
L PI N
O-RIN G
Replace .
WATER PUM PInspection , pag e 10-1 1 DOWE LPIN
SPECIA L BOL T
6 x 1. 0 mm : 7 BOLT S
1 2 N- m (1. 2 kg-m , 9 Ib-ft )
Replace .
WATER PASSAG E
O-RING S
Replace .
CONNECTIN
G PIP E
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Inspection


Replacement
1. Remove the timing belt (see page 6-15) ('91-'93) or

('94-'96).

2. Check that the water pump pulley turns counterclock-

wise.

3. Check for signs of seal leakage.
NOTE: A small amount of "weeping" from the bleed
hole is normal.

Turns
counterclockwise

BLEED HOLE
BLEED HOLE

1. Remove the timing belt (see page 6-15 ('91-'93) or
('94-'96).

2. Unscrew the bolts, then remove the water pump.
NOTE: Inspect and clean the 0-ring groove and
mating surface with the cylinder block.

DOWEL PIN
SPECIAL BOLTS
6 x 1.0 mm: 7 BOLTS
12 N·m

(1 .2 kg-m, 9 Ib-ft)

Replace,

WATER PUMP
0-RING

Replace.
SPECIAL BOLTS
8 x 1.25 mm: 2 BOLTS

22 N·m
(2.2 kg-m,
16 Ib-ft)
Replace.

3. Install the water pump in the reverse order of
removal.

NOTE:
Keep the 0-ring in position when installing.
Clean up spilled engine coolant.ProCarManuals.com

Special Tool s
11-151,11-155, 11-163,
11-164, 11-168, 11-169,
11-170, 11-171, 11-173
11-173
11-38
11-40
11-133, 11-137
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Component Location s
Index
EXHAUS T GA S RECIRCULATIO N (EGR ) VALV E
an d LIF T SENSO R
THROTTL E POSITIO N (TP ) SENSO R
EVAPORATIV E EMISSIO N (EVAP )
PURG E FLO W SWITC H ENGIN
E COOLAN T TEMPERATUR E (ECT ) SENSO R
INTAK E AI R TEMPERATUR E (IAT ) SENSO R
CRANKSHAF T POSITION /
CYLINDE R POSITIO N
(CKP/CYP ) SENSO R
FUE L PUM P RESISTE R
Troubleshooting , pag e 11-14 1
FUE L
INJECTO R
RESISTE RTesting,page 11-13 6
THROTTL E VALV E
CONTRO L MOTO R
CONTRO L BO X
page , 11- 8
NEUTRA L SWITC H (M/ T only )
Troubleshooting , pag e 11-12 3
FRON T KNOC K SENSO R (KS2 )
REAR KNOC K SENSO R (KS1 )
SPAR K PLU G VOLTAG E
DETECTIO N MODUL E
FRON T PRIMAR Y HEATE D
OXYGE N SENSO R (HO2S )
(BAN K 2 , SENSO R 1 )
SPAR K PLU G VOLTAG E SENSO R
(buil t int o th e IGNITIO N COI L
Assy. )
FRONT SECONDAR Y HEATE D OXYGE N
SENSO R (HO2S ) (BAN K 2 , SENSO R 2 )
REA R PRIMAR Y HEATE DOXYGEN SENSO R (HO2S )
(BAN K 1 , SENSO R 1 )
REAR SECONDARY HEATED OXYGEN SENSOR
(HO2S ) (BAN K 1, SENSO R 2)
For Troubleshooting of DTC related components. see chart on page 11-52.
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Component Location s
Index
CLUTC H SWITC H (M/ T only )
Troubleshooting , pag e 11-12 4
ACCELERATOR POSITIO N (AP )
SENSO R
THROTTL E CABL EInspection/Adjustment , pag e 11-15 0
Installation , pag e 11-15 0
PGM-F I
MAI N RELA Y
Rela y Testing , pag e 11-14 3
Troubleshooting , pag e 11-14 4
THROTTLE VALVECONTROL MOTOR RELAY
Troubleshooting , pag e 11-11 2
ENGIN E CONTRO L MODUL E (ECM )
Self-diagnosti c Procedures , pag e 11-3 8
Troubleshooting , pag e 11-6 1, and 11-62 SERVIC
E CHEC K CONNECTO R (2P )
Self-diagnosti c Procedures , pag e 11-3 8
DAT A LIN K CONNECTO R (16P )
Self-diagnosti c Procedures , pag e 11-3 8
For Troubleshooting of DTC related components, see chart on page 11-52.
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FUEL TAN K EVAPORATIV E EMISSIO N(EVAP) VALV E
EVAPORATIV E EMISSIO N(EVAP) TW O WA Y VALV ETesting , pag e 11-17 3
FUEL FIL L CA P
EVAPORATIV E EMISSIO N(EVAP) CONTRO L CANISTE R FUE
L PUM P
Testing , pag e 11-14 2
Replacement , pag e 11-14 2
FUEL FEE D PIP E
FUE L FILTE R
Replacement , pag e 11-13 8
FUEL PRESSUR E REGULATO R
Testing , pag e 11-13 7
Replacement , pag e 11-13 8
FUEL RETUR N PIP E
FUE L
VAPO R HOS E FUE
L INJECTOR S
Replacement , pag e 11-13 4
FUE L RAI L
FUE L TAN K
Replacement , pag e 11-14 7
FUE L PUM P RELA Y
Troubleshooting , pag e 11-13 9
For Troubleshooting of DTC related components, see chart on page 11-52.
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Component Location s
Index
AIR CLEANE R (ACL )
Disassembly , pag e 11-14 9 THROTTL
E BOD Y (TB )
Inspection , pag e 11-15 1
Disassembly , pag e 11-15 2
POSITIVE CRANKCAS E VENTILATIO N (PCV ) VALV E
Inspection , pag e 11-16 6
INTAK E AI R DUC T
INTAK E AI R BYPAS S (IAB ) CONTRO L DIAPHRAG M
Troubleshooting , pag e 11-15 5
Test , pag e 11-15 7 INTAK
E AI R BYPAS S (IAB ) VALV E BOD Y ASSEMBL Y
For Troubleshooting of DTC related components, see chart on page 11-52.
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