fuel cap ACURA NSX 1991 Service Repair Manual

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

Fuel Suppl y Syste m
Fuel Pressur e
Relieving
Before disconnectin g fue l pipe s o r hoses , releas e pres -
sur e fro m th e syste m b y loosenin g th e 6 m m servic e
bol t o n to p o f th e fue l filter .
• D o no t smok e whil e workin g o n th e fue l system .
Kee p ope n flame s o r spark s awa y fro m you r wor k
area.
• B e sur e t o reliev e fue l pressur e whil e th e ignitio n
switc h i s off .
1 . Disconnec t th e batter y negativ e cabl e fro m th e bat -
ter y negativ e terminal .
2 . Remov e th e fue l fil l cap .
3 . Plac e a bo x en d wrenc h o n th e 6 m m servic e bol t a t
th e fue l filter , an d hol d th e specia l banj o bol t wit h
anothe r wrench .
4 . Plac e a ra g o r sho p towe l ove r th e 6 m m servic e
bolt.
5. Slowl y loose n th e 6 m m servic e bol t on e complet e
turn.
NOTE :
• A fue l pressur e gaug e ca n b e attache d a t th e 6 m m
servic e bol t hole .
• Alway s replac e th e washe r betwee n th e servic e
bol t an d th e specia l banj o bol t wheneve r th e ser -
vic e bol t i s loosened .
• Replac e al l washer s wheneve r th e bolt s ar e
removed .
ProCarManuals.com

Evaporative Emission (EVAP) Controls

Description

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The

system consists of the following components:

A. Evaporative Emission (EVAP) Control Canister

An EVAP control canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from the

EVAP control canister into the engine and burned.

B. Vapor Purge Control System

EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a port

on the throttle body. The purging vacuum is controlled by the EVAP purge control diaphragm valve and the EVAP

control solenoid valve.

EVAP PURGE CONTROL SOLENOID VALVE OFF AFTER

STARTING ENGINE

ENGINE COOLANT TEMPERATURE ABOVE 153°F (67°C)

To No. 5 BACK-UP LIGHTS

ALTERNATOR TURN SIGNALS

(15 A) FUSE

FRESH

AIR
EVAP

PURGE CONTROL

DIAPHRAGM VALVE
EVAP PURGE

CONTROL

SOLENOID VALVE
EVAP PURGE

FLOW SWITCH
C. Fuel Tank Vapor Control System

When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens and

regulates the flow of fuel vapor to the EVAP control canister.

EVAP

TWO WAY

VALVE
FUEL

FILL CAPProCarManuals.com

Engine Oil

Replacement

CAUTION: Remove the drain plug carefully while the en-

gine is hot, the hot oil may cause scalding.

1. Warm up the engine.

2. Drain the engine oil.

WASHER

Replace.

DRAIN PLUG

45 IM-m (4.5 kg-m, 33 Ib-ft)

3. Reinstall the drain plug with a new washer, and refill

with the recommended oil.

CAUTION: Do not overtighten the drain plug.

Requirement
API Service Grade: Use "Energy

Conserving II" SG or SH grade oil.

SAE
10W-30
preferred.

You can also an oil a cantainer that

bears API CERTIFICATION mark.

Capacity
5.0
(5.3
US qt, 4.4 Imp qt)

at change, including filter.

6.3
(6.7
US qt, 5.5 Imp qt)

after engine overhaul.

Change
Every 7,500 miles (12,000 km) or

6 months whichever comes first.
API CERTIFICATION MARK

The numbers in the middle of the API Service label tell

you the oil's SAE viscosity or weight. Select the oil for

your car according to this chart:

Ambient Temperature

An oil with a viscosity of 10W —30 is preferred for im-

proved fuel economy and year-round protection in the

car.

You may use a 5W —30 oil if the climate in your area is

limited to the temperature range shown on the chart.

4. Fill the engine with oil up to the specified level, run

the engine for more than 3 minutes, then check for

oil leakage and oil level.ProCarManuals.com

Engine Removal/Installation

(cont'd)

Torque the engine mounting bolts in sequenceshown below.
CAUTION: Failure to tighten the bolts in the proper

sequence can cause excessive noise and vibration

and reduce bushing life; check that the bushings

are not twisted or offset.
Bleed air from the cooling system (see section 10)
Bleed air from the brake lines (see section 19)
Adjust the throttle cable tension.
Check the clutch pedal free play.
Adjust the clutch guide assemblies when
disassembling clutch (see section 12). Check that the transmission shifts into gear
smoothly (M/T see section 13, A/T see section 14).
Adjust the alternator belt (see section 23).
Adjust the A/C belt (see section 22).
Clean battery posts and cable terminals with sand-
paper, assemble, then apply grease to prevent

corrosion.

Inspect for fuel leakage:
• After assembling fuel line parts, turn on the igni- tion switch (do not operate the starter) so that
the fuel pump operates for approximately two seconds and the fuel line pressurizes. Repeat
this operation two or three times and check whether any fuel leakage has occurred at any
point in the fuel line.
Check and adjust wheel alignment.

10 x
1.25
mm

60 N .
m (6.0 kg-m, 43 Ib-ft)
MOUNTING BOLT SPECIAL BOLT

12 x
1.25
mm

77 N .
m
(7.7 kg-m,
56 Ib-ft)

Replace.
10 x
1.25
mm

60 N .
m
(6.0 kg-m
43 Ib-ft) 73 N.m (7.3 kg-m, 53 Ib-ft)

12 x
1.25
mm

95 N .
m
(9.5 kg-m,
69 Ib-ft)

RUBBER CAP

(M/T only)
SIDE MOUNT
: CORROSION RESISTANT
BOLT/NUT

12 x
1.25
mm

105 N .
m (10.5 kg-m, 76 Ib-ft)

10 x
1.25
mm

60 N .
m (6.0 kg-m, 43 Ib-ft) MOUNTING BOLT FRONT MOUNT
TRANSMISSION
MOUNT (A/T)

12 x
1.25
mm

95 N .
m
(9.5 kg-m,
69 Ib-ft)
SEAT STOPPER
TRANSMISSION
MOUNT (A/T)

REAR MOUNT
SPECIAL NUT
12 x
1.25
mm

77 N .
m
(7.7 kg-m,
56 Ib-ft)

Replace.
M/T:

A/T:

After the engine is in place:ProCarManuals.com

Component Locations

Index
FUEL TANK EVAPORATIVE EMISSION(EVAP) VALVE
EVAPORATIVE EMISSION (EVAP) TWO WAY VALVE

Testing, page 11-157
FUEL PUMP

Troubleshooting, page 11-116
Testing, page 11-119

Replacement, page 11-119
FUEL FEED PIPE
FUEL FILTERReplacement, page 11-114
FUEL PRESSURE REGULATOR
Testing, page 11-113

Replacement, page 11-114

FUEL RETURN PIPE
FUEL INJECTORS

Troubleshooting, page 11-107
Replacement, page 11-110
FUEL PUMP RELAY

Troubleshooting, page 11-116
FUEL RAIL
FUEL TANK
Replacement, page 11-126

FUEL

VAPOR HOSE
EVAPORATIVE EMISSION
(EVAP) CONTORL CANISTER

Troubleshooting, page 11-154

FUEL FILL CAPProCarManuals.com

System Description
The fuel supply system consists of a fuel tank, in-tank high pressure fuel pump, fuel pump relay, fuel pump
resistor, PGM-FI main relay, fuel filter, fuel pressureregulator, fuel injectors and fuel injector resistor.
This system delivers pressure-regulated fuel to the fuel injectors and cuts the fuel delivery when the engine is
not running. Fuel Pressure

Relieving
Do not smoke while working on the fuel system.
Keep open flames or sparks away from your work

area.
Be sure to relieve fuel pressure while the engine is

off.

NOTE: Before disconnecting fuel pipes or hoses,
release pressure from the system by loosening the 6
mm service bolt at top of the fuel filter. 1. Disconnect the battery negative cable from the battery negative terminal.

2.
Remove
fuel
fill
cap.
3. Use a box end wrench on the 6 mm service bolt at the fuel filter, while holding the special banjo boltwith another wrench.
4. Place a rag or shop towel over the 6 mm service bolt.
5. Slowly loosen the 6 mm service bolt one complete turn.

SERVICE BOLT
12 N .
m (1.2 kg-m, 9lb-ft)

SHOP

TOWEL
FUEL FILTER

NOTE:
A fuel pressure gauge can be attached at the 6 mm

service bolt hole.

Always replace the washer between the service bolt
and the special banjo bolt, whenever the service

bolt is loosened to relieve fuel pressure.
Replace all washers whenever the bolts are
removed to disassemble parts.

(cont'd)ProCarManuals.com

Testing

Do not smoke during the test. Keep open

If you suspect a problem with the fuel pump, check that
the fuel pump actually runs; When it is ON, you will hear some noise if you hold your ear to the fuel fill port with
the fuel fill cap removed. The fuel pump should run for
two seconds when the ignition switch is first turned on. If the fuel pump does not make noise, check as follows:
1. Remove the seat back panels.
2. Disconnect the C489 (6P) connector (located behind the seat back panels).
CAUTION: Be sure to turn the ignition switch OFF
before disconnecting the wires.
3. Disconnect the PGM-FI main relay connector and connect the BLK/YEL wire and BLK/YEL wire
with a jumper wire.
1. Remove the fuel tank (see page 11-126).
2. Disconnect the connector from the fuel pump.
3. Remove the fuel pump mounting nuts.
4. Remove the fuel pump from the fuel tank.
If battery voltage is available, replace the fuel
pump.
If there is no voltage, check the fuel pump
ground and wire harness (see page 11-122).
4. Check that battery voltage is available at the fuel
pump connector when the ignition switch is turned
ON (positive probe to the BLK/YEL wire, negative
probe to the BLK wire).

C489 CONNECTOR (6P)

BLK/

RED (+)

BLK (-)

JUMPER WIRE

flame away from your work area.

Replacement

Do not smoke while working on fuel

system. Keep open flames away from your work area.

28 N.
m (2.8 kg-m, 20 Ib-ft)

6 N.m
(0.6 kg-m,

4 Ib-ft)

FUEL PUMP

BRACKET

FUEL PUMP

PGM-FI

MAIN RELAY

BLK/
YEL

BLK/
YELProCarManuals.com

Emission Control System

Description

The evaporative emission controls are designed to minimize the amount of fuel vapor escaping to the atmosphere. The

system consists of the following components:

A. Evaporative Emission (EVAP) Control Canister

An EVAP control canister is used for the temporary storage of fuel vapor until the fuel vapor can be purged from the

EVAP control canister into the engine and burned.

B. Vapor Purge Control System

EVAP control canister purging is accomplished by drawing fresh air through the EVAP control canister and into a port

on the throttle body. The purging vacuum is controlled by the EVAP purge control diaphragm valve and the EVAP

control solenoid valve.

C. Fuel Tank Vapor Control System

When fuel vapor pressure in the fuel tank is higher than the set value of the EVAP two way valve, the valve opens

and regulates the flow of fuel vapor to the EVAP control canister.
EVAP PURGE CONTROL SOLENOID VALVE OFF AFTER

STARTING ENGINE

ENGINE COOLANT TEMPERATURE ABOVE
158°F
(70°C)
Evaporative Emission (EVAP) ControlsProCarManuals.com

FUEL

FILL CAP

FUEL TANK

EVAP

CONTROL

CANISTER
FRESH

AIR
EVAP

PURGE CONTROL

DIAPHRAGM

VALVE

(cont'd)
BLK
ECM

TO No. 2

(15 A) FUSE

GRN
EVAP PURGE

CONTROL

SOLENOID VALVE

EVAP

TWO WAY

VALVEProCarManuals.com