fuel filter 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

10. Remove the engine cover stay from the strut brace,
then set the engine cover stay between the engine
cover and rear hatch latch (NSX-T open top),
CAUTION: Use a shop tower to avoid damaging

painted surfaces.

SHOP

TOWEL

11. Relieve fuel pressure by loosening the service bolt on the fuel filter about one turn (see section 11).
Do not smok* while working on fuel
system; Keep open flame or spark away from work

area. Drain fue1 only into an approved container.

12. Remove the fuel feed pipe and fuel return hose (see page 5-5 ('91-'93) or ('94-'96).

13. Remove the evaporative emission (EVAP) control
canister hose and brake booster vacuum hose (see
page 5-5 ('91-'93) or ('94-'96).
14. Disconnect the breather pipe and vacuum hose, then remove the air cleaner housing.

6 x 1.0 mm

10 N·m (1.0 kg-m, 7 lb-ftl

AIR CLEANER
HOUSING

BREATHER

PIPE

: CORROSION RESISTANT BOLT
15. Remove the Hoses, then remove the expansion tank
(see page 5-5 ('91-'93) or ('94-'96).
16. Removel the radiator hoses and heater hose (see
page 5-6 ('91-'93) or ('94-'96).

17. Disconnect the two connectors, then remove the
control box (see page 5-6 ('91-'93) or ('94-'96).

18. Remove the intake manifold plate and top cover.

INTAKE MANIFOLD

PLATE
6 x
1.0mm

12 N·m (12kg-m,

9 lb-ft)

TOP COVER

19. Remove the fuel injector covers.
6 x 1.0 mm
12 N·m (1-2 kg-m, 9 lb-ft)

FUEL INJECTOR

COVER

(cont'd)

ENGINE

COVER

STAYProCarManuals.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

Inspection
1 . Reliev e fue l pressur e (se e pag e 11-132 )
2 . Remov e th e servic e bol t o n th e fue l filte r whil e
holdin g th e banj o bol t wit h anothe r wrench . Attac h
th e specia l too l (se e pag e 11-38 ).
3 . Star t th e engine . *Measur e th e fue l pressur e wit h
th e engin e idlin g an d th e vacuu m hos e o f th e fue l
pressur e regulato r disconnecte d fro m th e fue l pres -
sur e regulato r an d pinched .
Pressur e shoul d be :
32 4 - 36 3 kP a (3. 3 - 3. 7 kgf/cm
2, 4 7 - 5 3 psi )
4 . Reconnec t vacuu m hos e to th e fue l pressur e regula -
tor.
Pressur e shoul d be :
250 - 30 4 kP a (2.5 5 - 3. 1 kgf/cm2, 3 6 - 4 4 psi )
FUE LPRESSUR EGAUGE07406-004000 1
CLAMP
FUEL PRESSUR EREGULATO R
If th e engin e wil l no t start , tur n th e ignitio n switc h o n
(II ) wai t fo r tw o seconds , tur n i t off , the n bac k o n
agai n an d rea d th e fue l pressure . I
f th e fue l pressur e i s no t a s specified , firs t chec k th e
fue l pum p (se e pag e 11-142 ). I f th e fue l pum p i s OK ,
chec k th e following :
— If th e fue l pressur e is highe r tha n specified , inspec t
for:
• Pinche d o r clogge d fue l retur n hos e o r line .
• Fault y fue l pressur e regulato r (se e pag e 11-137 ).
• Fault y fue l pum p rela y (se e pag e 11-139 ).
— If th e fue l pressur e is lowe r tha n specified , inspec t
for:
• Clogge d fue l filter .
• Fault y fue l pressur e regulato r (se e pag e 11-137 ).
• Leakage in th e fue l line .
• Fault y fue l pum p rela y (se e pag e 11-139 ).
ProCarManuals.com

Fuel Suppl y Syste m
Fuel Filte r
Do no t smok e whil e workin g o n fue l sys -
tem . Kee p ope n flam e awa y fro m you r wor k area .
Th e fue l filte r shoul d b e replace d ever y 4 year s o r 60,00 0
mile s (96,00 0 km) , whicheve r come s first , o r wheneve r
th e fue l pressur e drop s belo w th e specifie d valu e [32 4 -
36 3 kP a (3. 3 - 3. 7 kgf/cm
2, 4 7 - 5 3 psi ) wit h th e fue l pres -
sur e regulato r vacuu m hos e disconnected ] afte r makin g
sur e tha t th e fue l pum p an d th e fue l pressur e regulato r
are OK .
1. Plac e a sho p towe l unde r an d aroun d th e fue l filter .
2 . Reliev e fue l pressur e (se e pag e 11-132 ).
3 . Remov e th e 1 2 m m banj o bol t an d th e fue l fee d
pipe fro m th e filter .
4. Remov e th e fue l filte r clam p an d fue l filter .
5 . Whe n assembling , us e ne w washer s a s shown .
ProCarManuals.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

12. Remove the intake manifold plate and the top
cover.
13. Remove the throttle cable by loosening the locknut, then slip the cable end out of the throttle bracketand accelerator linkage.

INTAKE MANIFOLD
TOP COVER
6 x 1.0 mm

12 N .
m (1.2 kg-m, 9 Ib-ft)

PLATE

ADJUSTING NUT

LOCKNUT
CABLE END

14. Relieve fuel pressure by slowly loosening the ser-
vice bolt on the fuel filter about one turn (see sec-

tion 11 ).

1 5. Remove the fuel feed pipe.
16. Remove the fuel return hose from the pressure con- trol valve.

6 x 1.0 mm

22 N .
m (2.2 kg-m. 16 Ib-ft) 12 N .
m (1.2 kg-m, 9 Ib-ft)
FUEL FEED
PIPE
WASHERS

Replace.

FUEL RETURN
HOSE

17. Disconnect two hoses, then remove the expansion tank.

6 x 1.0 mm
10 N .
m (1.0 kg-m, 7 Ib-ft)
EXPANSION TANK
WATER HOSES
(cont'd)

Do not smoke while working on the
fuel system. Keep open flame away from work
area. Drain fuel only into an approved container.
CAUTION:
THROTTLE CABLE

NOTE:

Take care not to bend the cable when removingit. Always replace a kinked cable with a new
one.
Adjust the throttle cable when installing (see
section 11).
Before disconnecting any fuel line, relieve the
fuel pressure as described above.
Place a shop towel over the fuel filter to prevent
pressurized fuel from spraying over the engine.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
Vacuum Connections (cont'd)
FRONT HEATED OXYGEN SENSOR (HO2S)
REAR HEATED OXYGEN SENSOR (HO2S)
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSORINTAKE AIR TEMPERATURE (IAT) SENSOR
FRONT KNOCK SENSOR (KS)
REAR KNOCK SENSOR (KS) IDLE AIR CONTROL (IAC) VALVE
FAST IDLE THERMO VALVE
AIR CLEANER (ACL) FUEL INJECTORFUEL PRESSURE REGULATOR
FUEL FILTER
FUEL PUMP (FP)
FUEL TANK
THROTTLE VALVE DASHPOT CONTROL DIAPHRAGM
THROTTLE VALVE DASHPOT CHECK VALVE INTAKE AIR BYPASS (IAB) CHECK VALVE
INTAKE AIR BYPASS (IAB) VACUUM TANK
INTAKE AIR BYPASS (IAB) CONTROL SOLENOID VALVE
INTAKE AIR BYPASS (IAB) CONTROL DIAPHRAGM
FRONT THREE WAY CATALYTIC CONVERTER (TWC)
REAR THREE WAY CATALYTIC CONVERTER (TWC)
POSITIVE CRANKCASE VENTILATION (PCV) VALVE
EXHAUST GAS RECIRCULATION (EGR) VALVE
EXHAUST GAS RECIRCULATION (EGR) VALVE LIFT SENSOR
EXHAUST GAS RECIRCULATION (EGR) VACUUM CONTROL VALVE
EXHAUST GAS RECIRCULATION (EGR) CONTROL SOLENOID VALVE
EVAPORATIVE EMISSION (EVAP) CONTROL CANISTER
EVAPORATIVE EMISSION (EVAP) PURGE CONTROL SOLENOID VALVE
EVAPORATIVE EMISSION (EVAP) PURGE CONTROL DIAPHRAGM VALVE
EVAPORATIVE EMISSION (EVAP) TWO WAY VALVEProCarManuals.com

Fuel Supply System

System Troubleshooting Guide

NOTE: Across each row in the chart, the sub-systems that could be sources of a symptom are ranked in the order they should be inspected starting with . Find the symptom in the left column, read across to the most likely source, then
refer to the page listed at the top of that column. If inspection shows the system is OK, try the next most likely system
,
etc.

PAGE
SUB-SYSTEM
FUEL
INJECTOR FUEL
INJECTOR

RESISTOR
FUEL

PRESSURE

REGULATOR
FUEL

FILTER
FUEL
PUMP PGM-FI

MAIN

RELAY
FUEL PUMP

RELAY

FUEL PUMP
RESISTOR
CONTAMI-
NATED FUEL
SYMPTOM
ENGINE WON'T START
DIFFICULT TO START ENGINE
WHEN COLD OR HOT ROUGH IDLE
107


112

113

114

115


120

116,
124

POOR

PERFORMANCE
MISFIRE OR

ROUGH

RUNNING

FAILS

EMISSION
TEST
LOSS OF
POWERProCarManuals.com