sensor ACURA NSX 1991 Service User Guide

PGM-FI Syste m
Engine Contro l Modul e (ECM )
(From pag e 11-63 )
Chec k fo r a shor t i n th e A P sen -
sor:1. Tur n th e ignitio n switc h OFF .2. Connec t th e SC S servic e con -
nector .
3 . Disconnec t th e A P senso r 3 P
connector .
4. Tur n th e ignitio n switc h O N (II) .
Is DT C P124 6 and/o r P124 7
indicated ?
Chec k fo r a shor t i n th e wire s
(VC C lines) :
1. Tur n th e ignitio n switc h OFF .2. Disconnec t th e EC M connec -tor D (22P ) an d F (26P) .3. Chec k fo r continuit y betwee nbody groun d an d EC M con -necto r terminal s D10 , F 1 an dF14 individually .
Is ther e continuity ?
I s ther e batter y voltage ?
Chec k fo r a n ope n i n th e wire s
(L G lines) :
1 . Reconnec t al l senso r connec -
tors.2. Reconnec t th e EC M connecto rD (22P ) F (26P) .3. Tur n th e ignitio n switc h O N (II) .4. Measur e voltag e betwee n
bod y groun d an d EC M connec -
tor terminal s A2 6 an d B 9 indi -vidually .
I s ther e les s tha n 1. 0 V ?
Substitut e a known-goo d EC M
an d recheck . I f symptom/indica -
tio n goe s away , replac e th e origi -
nal ECM .
Replac e th e A P sensor .
Repai r shor t t o bod y groun d
in th e wir e betwee n EC M(D10 ) an d throttl e angl e sen -
so r an d EG R valv e lif t sensor .
Repai r shor t t o bod y groun d in
th e wir e betwee n EC M (F1 )and MA P senso r o r Accelerato r
Positio n sensor .
Repai r shor t t o bod y groun d in
th e wir e betwee n EC M (F14 )
an d Accelerato r Positio n sen -
sor.
WIR E SID E O F FEMAL E TERMINAL S
Repai r ope n i n th e wire(s )
between EC M (A13 , C D an dPGM-F I mai n relay .
Chec k fo r poo r connection s
o r loos e wire s a t th e PGM-F I
mai n relay .
ECM CONNECTOR S
WIR E SID E O F FEMAL E TERMINAL S
Repai r ope n i n th e wire(s )
between EC M (A26 , B9 ) an dG10 1 tha t ha d mor e tha n 1. 0 V .
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Drive By Wire System

System Description

The Drive By Wire System is an electronic throttle control system.

This system consists of the throttle valve control motor and Throttle Position (TP) sensor assembled in Throttle Body (TB),

the accelerator position sensor, and the Engine Control Module (ECM).

To THROTTLE

VALVE CONTROL

MOTOR RELAY

THROTTLE

VALVE

CONTROL

MOTOR

Drive By Wire System Functions:

Idle Control Function

When the engine is idling, the ECM controls the throttle valve control motor to maintain the proper idle speed according

to engine loads.

Acceleration Control Function

When the accelerator pedal is depressed, the ECM opens the throttle valve depending on the accelerator position sensor

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Drive B y Wir e Syste m
System Descriptio n
Cruise Contro l Functio n
Th e EC M control s th e throttl e valv e contro l moto r t o maintai n th e se t spee d whe n th e cruis e contro l syste m is operating .
Th e throttl e valv e contro l moto r take s th e plac e o f th e cruis e contro l actuator .
Tractio n Contro l Syste m (TCS ) Functio n
I f whee l spi n occur s durin g acceleratio n o r cornering , th e TC S contro l uni t request s th e EC M to reduc e th e engin e powe r
b y retardin g th e ignitio n timin g an d closin g th e throttl e valve . I f th e wheel s loc k during deceleration , th e TC S contro l uni t
signal s th e EC M to ope n th e throttl e valve .
Engin e Protectio n Functio n
Whe n th e engin e spee d exceed s 8,00 0 rp m (M/T ) o r 7,50 0 rp m (A/T) , th e EC M control s th e throttl e valve , regardles s o f th e
accelerato r position , t o protec t th e engin e fro m over-revving .
Fail-saf e Functio n
O n thi s system , th e EC M monitor s th e positio n o f th e accelerato r peda l wit h a dua l circui t typ e accelerato r positio n sensor ,
an d monitor s th e operatio n o f th e throttl e valv e contro l moto r wit h a Throttl e Positio n (TP ) sensor .
Whe n a n abnormalit y occur s i n th e system , th e EC M restrict s th e operatio n o f th e throttl e valv e contro l moto r t o allo w th e
engin e t o continu e t o run .
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Fuel Suppl y Syste m
Fuel Injector s
Replacemen t
Do no t smok e durin g th e work . Kee p ope n flame s awa y fro m you r wor k area .
1 . Reliev e fue l pressur e (se e pag e 11-132 ).
2 . Remov e th e intak e manifol d covers .
3. Disconnec t th e connector s fro m th e fue l injector s an d th e IA T sensor .
4 . Disconnec t th e vacuu m hos e an d fue l retur n hos e fro m th e fue l pressur e regulator .
NOTE: Plac e a ra g o r sho p towe l ove r th e hose s befor e disconnectin g them .
5. Disconnec t th e fue l hos e fro m th e fue l rail .
6. Loose n th e retaine r nut s o n th e fue l rai l an d harnes s holder .
7. Disconnec t th e fue l rail .
8. Remov e th e fue l injector s fro m th e intak e manifold .
O-RINGReplace .
CUSHIONRINGReplace .
SEAL RIN GReplace .
FUEL INJECTO R
INSULATO R
Replace.
9. Slid e ne w cushio n ring s ont o th e fue l injectors .
10 . Coa t ne w O-ring s wit h clea n engin e oil , an d pu t the m o n th e fue l injectors .
11 . Inser t th e fue l injector s int o th e fue l rai l first .
12 . Coa t ne w sea l ring s wit h clea n engin e oil , an d pres s the m int o th e intak e manifold .
FUELPRESSUR EREGULATO R
FUEL RAI L
HARNESS ,HOLDER
22 N- m(2.2 kgf-m ,16 Ibf-ft )
INTAK E
MANIFOL D
COVERS
12 N- m(1.2 kgf-m ,8.7 Ibf-ft )
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13. Install the fuel injectors and fuel rail assembly in the manifold.

CAUTION: To prevent damage to the O-rings, install the fuel injectors in the fuel rail first, then install them in the

intake manifold.

FUEL

RAILS

FUEL RAIL

INSULATOR

FUEL RAIL
14. Align the center line on the connector with the mark on the fuel rail.

15. Install and tighten the retainer nuts.

16. Connect the fuel hose to the fuel rail.

17. Connect the vacuum hose and fuel return hose to the fuel pressure regulator.

18. Install the connectors on the fuel injectors and the IAT sensor.

19. Install the intake manifold covers.

20. Turn the ignition switch ON (II), but do not operate the starter. After the fuel pump runs for approximately two seconds,

the fuel pressure in the fuel line rises. Repeat this two or three times, then check whether there is any fuel leakage.
MARKINGSProCarManuals.com

Intake Air System

System Description

The system supplies air for all engine needs. It consists of the intake air pipe, Air Cleaner (ACL), intake air duct, throttle

body, and intake manifold. A resonator in the intake air duct provides additional silencing as air is drawn into the system.

IAB CONTROL

SOLENOID VALVE

To No. 5 BACK-UP LIGHTS

ALTERNATOR TURN SIGNALS

(15 A) FUSE

IAB

CONTROL

DIAPHRAGM

IAB

CONTROL

VALVE
THROTTLE

VALVE
INTAKE

AIR DUCT
ACL
RESONATOR
VARIOUS

SENSORS

INTAKE

MANIFOLDProCarManuals.com

Intake Ai r Syste m
Throttl e Cabl e
Inspection/Adjustmen t
1 . Remov e th e accelerato r positio n senso r cover .
2. Chec k tha t th e throttl e cabl e operate s smoothl y wit h
no bindin g o r sticking . Repai r a s necessary .
3 . Chec k cabl e fre e pla y a t th e throttl e linkage . Cabl e
deflectio n shoul d b e 1 0 - 1 2 m m (0.3 9 - 0.4 7 in.) .
ACCELERATO RPOSITIONSENSOR COVE R
DEFLECTIO N10 - 1 2 m m(0.3 9 - 0.47 in. )
LOCKNU T
CABLE
BRACKE T
ADJUSTIN G NU T
4. I f deflectio n i s no t withi n specs , loose n th e locknut ,
tur n th e adjustin g nu t unti l th e deflectio n i s a s spec -
ifie d the n retighte n th e locknut . Installatio
n
1 . Rotat e th e throttl e linkag e counterclockwise , the n
instal l th e throttl e cabl e i n th e throttl e linkag e an d
instal l th e cabl e housin g i n th e cabl e bracket .
THROTTL E LINKAG E
CABLE
BRACKE T
INNERWIRE
LOCKNU TADJUSTIN GNUT
2. Hol d th e cabl e sheath , removin g al l slac k fro m th e
cable .
3. Tur n th e adjustin g nu t unti l i t i s 3 m m (0.1 2 in. )
awa y fro m th e cabl e bracket .
4 . Tighte n th e locknut . Th e cabl e deflectio n shoul d no w
b e 1 0 - 1 2 m m (0.3 9 - 0.4 7 in.) . I f not , se e inspection /
adjustment .
LOCKNUT9.8 N- m(1.0 kgf-m ,
7. 2 Ibf-ft )
ADJUSTIN GNUT
CABL EBRACKE T
3 m m(0.1 2 in. )
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Intake Air System

Throttle Body

Disassembly

THROTTLE BODY

IDLE ADJUSTING

SCREW

O-RING

Replace.

THROTTLE VALVE

CONTROL MOTOR

INTAKE AIR DUCT
TP SENSOR

22 N-m

(2.2 kgf-m,

16 Ibf-ft)ProCarManuals.com

Three Way Catalytic Converter (TWC)

Description

The Three Way Catalytic Converter (TWC) is used to convert hydrocarbons (HC), carbon monoxide (CO), and oxides of

nitrogen
(NOx)
in the
exhaust
gas to
carbon
dioxide
(CO2),
dinitrogen
(Nz)
and
water
vapor.

SECONDARY HEATED OXYGEN SENSOR (SENSOR 2)

THREE WAY

CATALYST

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Exhaust Ga s Recirculatio n (EGR ) Syste m
The EG R syste m is designe d t o reduc e oxide s o f nitroge n emission s (NOx ) b y recirculatin g exhaus t ga s throug h th e EG R
valv e an d th e intak e manifol d int o th e combustio n chambers . I t i s compose d o f th e EG R valve , EG R vacuu m contro l valve ,
EGR contro l solenoi d valve , EC M an d variou s sensors .
The EC M contain s memorie s fo r idea l EG R valv e lift s fo r varyin g operatin g conditions . Th e EG R valv e lif t senso r detect s
th e amoun t o f EG R valv e lif t an d send s th e informatio n t o th e ECM . Th e EC M the n compare s it wit h th e idea l EG R valv e lif t
whic h i s determine d b y signal s sen t fro m th e othe r sensors . I f ther e is an y differenc e betwee n th e two , th e EC M varie s cur -
ren t t o th e EG R contro l solenoi d valv e to regulat e vacuu m applie d t o th e EG R valve .
EGRVALV ELIFTSENSO R
INTAKEMANIFOL D
To No . 5 BACK-U P
LIGHT S ALTERNATO R
TUR N SIGNAL S
(1 5 A ) FUS E
EGRVACUU MCONTRO LVALVE
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