engine ACURA NSX 1991 Service User Guide

9. Relieve fuel pressure by loosening the service bolt
on the fuel filter about one turn (see section 11).
Do not smoke while working on the
fuel
system.
Keep open flame away from work
area. Drain fuel only into an approved container.
10. Remove the fuel feed pipe and fuel return hose.
11. Remove the wire harness cover, then remove the fuel pipe clamp.

22 N·m
(2.2 kg-m,
16 Ib-ft)

WIRE HARNESS

COVER
6 x 1.0 mm

12 N·m
(1.2 kg-m,

9 lb-ft)

FUEL FEED
PIPE

WASHERS
Replace.

FUEL RETURN

HOSE

12. Remove the brake booster vacuum hose and evapo- rative emission (EVAP) control canister hose.

BRAKE BOOSTER

VACUUM HOSE

EVAP CONTROL

CANISTER HOSE
13. Remove the expansion tank cap.

14. Raise the hoist to full height.
15. Drain the engine coolant (see page
10-5).
Loosen the drain plug from the radiator lower
tank. Remove two drain bolls from the water pipes.
Reinstall the drain bolts with new washers.
Loosen the front and rear engine drain bolts to
drain engine coolant from the cylinder heads.
Connect rubber hoses to the drain bolts.
16. Drain the transmission oil/fluid. Reinstall the drain plug with a new washer.
17. Drain the engine oil. Reinstall the drain plug with a
new washer.

18. Lower the hoist, then remove the air cleaner hous-

ing (see page 6-25 ('91-'93 Mode ls),or('95-'96 Models).

19. Disconnect two hoses, then remove the expansion

tank.

6 x 1.0 mm

10 N·m
11.0 kg-m,

7 lb-ft)

EXPANSION

TANK

WATER BYPASS

HOSES
(cont'd)ProCarManuals.com

Engine Removal/Installation

Removal

20. Disconnect the engine wire harness connectors.

21. Remove the battery cable from the main fuse box.

ENGINE WIRE

HARNESS CONNECTORS

BATTERY

CABLE

6 x 1.0 mm

10 N-m
(1.0 kg-m,

7 Ib-ft)

22. Disconnect the throttle body 6P connector, and

remove the ground cable and starter cable.

STARTER CABLE
THROTTLE BODY

6P CONNECTOR

GROUND CABLE

CORROSION RESISTANT BOLT
23. Disconnect the two connectors from the emission

control box, then remove the control box.

• Do not disconnect the vacuum hoses.

6 x 1.0 mm

10 N-m (1.0 kg-m, 7 Ib-ft)

CONNECTORS

CONTROL BOX

24. Remove the radiator hoses and heater hose.

HEATER HOSE

RADIATOR

HOSESProCarManuals.com

Engine Removal/Installatio n
Removal
32. Remov e th e lef t an d righ t parkin g brak e cable s (se e
sectio n 19 ).
33 . Remov e th e rea r bea m ro d assembl y an d parkin g
brak e cabl e clamps . '
1 0 x 1.2 5 mm60 N- m (6. 0 kg-m ,43 Ib-ft )
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )
34. Remov e th e fron t engin e mount , the n remov e th e
fron t beam .
12 x 1.2 5 mm77 N- m (7. 7 kg-m , 5 6 Ib-ft )
Replace .
12 x 1.2 5 mm -95 N- m (9. 5 kg-m ,69 Ib-ft )
CORROSIO N RESISTAN T BOLT/NU T
35. Remov e th e A/ C compresso r (se e sectio n 22 ), the n
suspen d it fro m th e body .
NOTE :
• D o no t remov e th e compresso r hoses .
• D o no t le t th e compresso r han g b y it s hoses .
36 . Reinstal l th e fron t bea m an d fron t engin e mount .
Han g wit h wir e
or rope .
A/C COMPRESSO R
37. Remov e th e rea r brak e hoses , the n plu g th e brak e
pipe s wit h rubbe r cap s (se e sectio n 19 ).
38 . Disconnec t th e lef t rea r whee l senso r connector ,
then remov e th e whee l senso r wir e clamp s an d sta -
bilize r link .
6 x 1. 0 m m10 N- m (1. 0 kg-m ,7 Ib-ft )
LEFT REA R
WHEE L SENSO R
CONNECTO R
SELF-LOCKIN G NU T
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )Replace .
STABILIZE R
LIN K SELF-LOCKIN
G NU T
12 x 1.2 5 mm85 N- m (8. 5 kg-m , 6 2 Ib-ft )Replace .
REAR BEA M
RO D ASSEMBL Y
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39. Remov e th e righ t whee l senso r wir e clamp s an d
stabilize r link .
6 x 1. 0 m m10 N- m (1. 0 kg-m ,7 Ib-ft )
STABILIZE RLINK
SELF-LOCKIN G NU T
12 x 1.2 5 mm95 N- m (9. 5 kg-m ,69 Ib-ft )Replace .
SELF-LOCKIN G NU T12 x 1.2 5 mm85 N- m (8. 5 kg-m , 6 2 Ib-ft )
Replace .
40. Disconnec t th e fron t secondar y heate d oxyge n senso r
connector , the n remov e th e fron t exhaus t pip e A an d
fron t thre e wa y catalyti c converte r (TWC) .
41 . Separat e th e rea r TW C fro m th e rea r join t pipe .
SELF-LOCKIN G NUT S10 x 1.2 5 mm34 N- m (3. 4 kg-m , 2 5 Ib-ft )Replace .
GASKET SReplace.
GASKETReplace .SELF-LOCKIN G NU T •10 x 1.2 5 mm55 N- m (5. 5 kg-m , 4 0 Ib-ft )Replace .
42. Positio n th e specia l too l unde r th e car . Lowe r th e ca r
jus t abov e th e fixture . Wit h th e hel p o f a n assistant ,
attac h th e fixtur e t o th e subfram e wit h tw o 1 2 m m
nut s an d tw o 1 0 m m bolts .
LOOSEL Y INSTAL L TW O 1 2 m m
NUT S O N STUD S HER E
ENGINE REMOVAL /
INSTALLATIO N
FIXTURE07MAK-PR7020 A
LOOSEL Y INSTAL L ON E
1 0 m m BOL T HER E
43. Adjus t th e pad s o n th e fixtur e t o suppor t th e oi l pa n
an d transmissio n housing .
44 . Lowe r th e ca r s o th e fixtur e i s restin g o n it s caster s
(o r appropriat e platform) .
45 . Remov e th e tw o bolt s fro m th e sid e engin e moun t
nea r th e alternator . Pivo t th e mountin g bracke t int o
th e housin g o f th e body .
BODY SUPPOR TBRACKET
SIDE ENGIN EMOUNT
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Engine Removal/Installatio n
Removal
46. Remov e th e transmissio n mountin g bolt .
MOUNTIN G BOL T
TRANSMISSIO NMOUNT
47. Remov e th e twelv e subframe-to-bod y mountin g
bolts.
48. Rais e th e ca r a fe w inches .
49. Chec k tha t al l wire s an d hose s ar e disconnecte d
from th e engin e assembly .
50 . Rais e th e ca r completel y of f th e engine/suspensio n
assembly . Rol l th e assembl y fro m unde r th e car . NOTE
: Perfor m step s 5 1 thr u 5 4 onl y i f th e engin e
assembl y is t o b e remove d fro m th e subframe .
51 . Remov e th e adjustin g bol t an d flang e bolt , the n
separat e th e lowe r contro l ar m fro m th e subfram e
(se e sectio n 18 ).
52 . Remov e th e flang e bolt , the n separat e th e to e contro l
ar m fro m th e subfram e (se e sectio n 18 ).
CAUTION : Mak e sur e tha t th e referenc e mark s o n
th e contro l ar m ar e aligned .
53 . Remov e th e hea t shiel d for m th e intermediat e shaf t
bearin g support , the n remov e th e driveshaft s (se e
sectio n 16 ).
NOTE :
• Coa t al l precisio n finishe d surface s wit h clea n
engin e oil .
• Ti e plasti c bag s ove r th e driveshaf t ends .
54 . Attac h a chai n hois t t o th e engine .
Remov e th e fron t an d rea r moun t mountin g bolts ,
the n separat e th e engine from th e suspensio n an d
th e bea m assembly .
CAUTION : D o no t hi t th e engin e oi l coole r o n th e
rea r righ t bea m bracket .
FRONT MOUN T
REAR MOUN T
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Installation
Additional Torqu e Valu e Specifications :
NOTE : Fo r manifol d replacement , refe r t o sectio n 9 .
Engine Removal/Installation
ProCarManuals.com

Engine Removal/Installatio n
Installation
Engine Installation :
Instal l th e engin e in th e revers e orde r o f removal . Reinstal l
th e moun t bolts/nut s i n th e followin g sequence , failur e t o
follo w thes e procedure s ma y caus e excessiv e nois e an d
vibration , an d reduc e bushin g life .
1 . Instal l th e rea r mount , the n tighte n th e bolt s o n th e
transmissio n side .
NOTE : D o no t tighte n th e mountin g bolt .
MOUNTIN G BOL T
Replace .
REA R MOUN T
M/T: 1 2 x 1.2 5 mm105 N- m (10. 5 kg-m , 7 6 Ib-ft )A/T: 1 0 x 1.2 5 mm60 N- m (6. 0 kg-m , 4 3 Ib-ft )
2. Instal l th e fron t mount , the n tighte n th e bolt s i n th e
numbere d sequenc e a s show n
FRONT MOUN T
12 x 1.2 5 mm77 N- m (7. 7 kg-m ,56 Ib-ft )Replace .
10 x 1.2 5 mm60 N- m (6. 0 kg-m , 4 3 Ib-ft )
CORROSIO N RESISTAN T BOLT/NU T
3. Instal l th e subframe , the n tighte n th e subframe-to -
bod y mountin g bolt s (se e sectio n 20 ).
NOTE : Alig n th e bol t hole s o f th e bea m bracket s
an d bod y wit h a tapere d punch .
GUIDE HOL E(BODY )
GUIDE HOL E
(SID E BEAM )
TAPERED PUNC H
4. Instal l th e transmissio n mount , the n tighte n th e bolt s
o n th e transmissio n side .
NOTE : D o no t tighte n th e mountin g bolt .
10 x 1.2 5 mm60 N- m (6. 0 kg-m ,43 Ib-ft )
MOUNTIN GBOLT
TRANSMISSIO NMOUNT
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5. Install the side engine mount, then tighten the bolts
in the numbered sequence as shown ( - ),

12 x
1.26
mm

73 N·m
(7.3 kg-m,
53 Ib-ft)

Replace.
12 x
1.25
mm

95 N·m
(9.5 kg-m,
69 Ib-ft)

SIDE ENGINE

MOUNT

6. Tighten the transmission mount mounting bolt.

MOUNTING BOLT
12 x
1.25
mm

95 N·m (9.5 kg-m, 69 Ib-ft)
7. Tighten the rear mount mounting bolt.
MOUNTING BOLT

12 x
1.25
mm

77 N·m (7.7 kg-m, 56 Ib-ft)
Replace.

Check that the spring clip on the end of each
driveshaft clicks into place.
CAUTION: Use new spring clips.
Bleed air from the cooling system (see page 10-5).
Bleed air from the brake lines {see section 19).
Check the clutch pedal free play (see section 12).

Adjust the clutch guide assemblies when disas-

sembling clutch (see section 12).

Check that the transmission shifts into gear

smoothly.

Adjust the alternator belt (see section 23).
Adjust the A/C compressor belt (see section 22).
Clean battery posts and cable terminals with
sandpaper, assemble, then apply grease to pre-
vent corrosion.
Inspect for fuel leakage (see section 11). After assembling the fuel line parts, turn on
the ignition switch (do not operate the starter) so that the fuel pump operates for approxi-
mately two seconds and the fuel line pressu-
rizes. Repeat this operation two or three times
and check for fuel leakage at any point in the

fuel line.

Check and adjust wheel alignment (see section 18).

Refill the engine with engine oil (see page 8-4 ('91-'92
Models), ('93-Model),or ('94-'96 Models).

Refill the transmission with oil/fluid (see section

13 or
14).ProCarManuals.com

Valve Clearance

Adjustment

NOTE:
Valves should be adjusted cold, when the cylinderhead temperature is less than 100°F (38°C).
Adjustment is the same for both intake and exhaust valves.
Adjust valve clearance at TDC of each cylinder.
Do not rotate the engine counterclockwise. The tim-
ing belt could jump a tooth on the camshaft pulleys.

1. Remove the cylinder head covers.
NOTE: Refer to pages 6-47 ('91-'93),or ('94-'96), 6-48
('91-'93), or ('94-'96) when installing the cylinder head cover.

FRONT:

No.6 No.5 No.4
EXHAUST

INTAKE

No.6 No.5 No.4

REAR:
No.3 No.2 No.1

INTAKE

EXHAUST

No.3 No.2 No.1 (cont'd)

CRANKSHAFT PULLEY
TDC MARK (WHITE PAINT)
POINTER ON

THE LOWER

COVER

REAR:

Number 1 PISTON at TDC

FRONT:

2. Rotate the crankshaft to set No. 1 piston at TDC.
TDC mark (white paint) on the crankshaft pulley
should align with pointer on the timing lower
cover, and TDC grooves on the camshaft pulleysshould align with timing belt cover plates.ProCarManuals.com

Timing Belt

Inspection

1. Remove the ignition coil covers and harness clamps.
2. Disconnect the connectors, then remove the ignition
coils.
3. Remove the cylinder head covers,
4. Inspect the timing belt for cracks and coolant or oil soaking.

NOTE:
Replace the belt if coolant or oil soaked.
Remove any oil or solvent that gets on the belt.

Inspect this area

for wear.

Rotate pulley and

Inspect belt.
Tension Adjustment

CAUTION:
Always adjust timing belt tension with the engine cold
Do not rotate the crankshaft when the adjusting bolt
is loose (the timing belt will skid over the teeth of
the rear intake caimshaft pulley).
Adjust the belt tension only when the belt has been
removed and reinstalled or replaced.

NOTE:
Tensioner is spring-loaded to apply proper tension to
the belt automatically after making the following ad-
justment. Inspect the timing belt before adjusting the belt
tension.
Always rotate the crankshaft clockwise. Rotating it
counterclockwise may result in improper adjustment
of the belt tension or cause the belt to jump a tooth
on the camshaft pulleys.
Install the timing beIt with the No. 1 piston at TDC
(see pages 6-18 ('91-'93) or ('94-'96),19 ('91-'93)
or ('94-'96) Remove the slack in the sequence of , and

by turning each camshaft pulley slightly.
Loosen the timing belt adjusting bolt 180° (the slack
at should be eliminated).

Then, tighten the timing belt adjusting bolt.

Verify that No. 1 piston is at TDC (see page 6-19).
Rotate the crankshaft clockwise nine teeth on the
camshaft pulley (The blue mark on the crankshaft pul- ley should line up with the pointer on lower cover).
Loosen
the
timing
belt
adjusting
bolt.

Retighten the adjusting bolt, torque to 43 N·m (4.3
kg-m, 31 Ib-fl).
Direction

of rotation

POINTER ON
LOWER COVER

ADJUSTING BOLT

43N·m (4.3 kg-m,

31 Ib-ft)
BLUE MARK
TDC MARK
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