1997 ACURA NSX light

Intake Ai r Syste m
Intake Ai r Bypas s (IAB ) Contro l Syste m (cont'd )
(From pag e 11-155 )
Chec k fo r vacuu m at 5,00 0 rpm :
1 . Rais e engin e spee d t o abov e
5,00 0 rpm .
2 . Chec k fo r vacuu m a t th e vac -
uu m hose .
I s ther e vacuum ?
IA B contro l syste m is OK . I
s ther e batter y voltage ?
Chec k fo r a n ope n i n th e wir e
(IABC S line) :
1 . Sto p th e engin e an d tur n th e
ignitio n switc h ON .2. Connec t EC M connecto r ter -minal s A2 0 t o A2 6 wit h ajumpe r wire .
Doe s th e solenoi d valv e clic k
whe n th e jumpe r i s connected ?
Substitut e a known-goo d EC M
an d rechec k (se e pag e 11-3 9 fo r
immobilize r information) . I f symp -
tom/indicatio n goe s away , replac e
th e origina l ECM .
I s ther e vacuum ?
Chec k fo r a shor t i n th e wir e
(IABC S line) :
1 . Tur n th e ignitio n switc h OFF .
2. Disconnec t th e EC M connec -tor A (26P ) fro m th e ECM .
3 . Chec k fo r continuit y betwee n
th e contro l bo x connecto r ter -
mina l No . 6 an d bod y ground .
I s ther e continuit y t o ground ?
Substitut e a known-goo d EC M
an d rechec k (se e pag e 11-3 9 fo r
immobilize r information) . I f symp -
to m goe s away , replac e th e origi -
nal ECM .
Repai r ope n i n th e wir e betwee n
th e contro l bo x 6 P connecto r an d
No . 5 BACK-U P LIGHT S ALTER -
NATO R TUR N SIGNAL S (I S A )
fus e in th e under-das h fus e box .
Repai r ope n i n th e wir e betwee n
EC M (A20 ) an d contro l bo x 6 P
connector .
Replac e th e IA B contro l solenoi d
valve.
Repai r shor t t o groun d a t th ewir e betwee n EC M (A20 ) an dcontro l bo x 6 P connector .
(Fro
m pag e 11-155 )
ProCarManuals.com

Emission Contro l Syste m
System Descriptio n
The emissio n contro l syste m include s tw o Thre e Wa y
Catalyti c Converter s (TWCs) , Exhaus t Ga s Recirculatio n
(EGR ) system , Positiv e Crankcas e Ventilatio n (PCV ) sys -
te m an d Evaporativ e Emissio n (EVAP ) Contro l system .
Th e emissio n contro l syste m is designe d t o mee t federa l
an d stat e emissio n standards .
Tailpipe Emissio n
1. Star t th e engine . Hol d th e engine at 3,00 0 rp m wit h
no loa d (A/ T in o r position , M/ T in neutral ) unti l
th e radiato r fa n come s on , the n le t i t idle .
2 . Connec t a tachometer .
3 . Chec k an d adjus t th e idl e speed , i f necessar y (se e
pag e 11-129 ).
4 . War m u p an d calibrat e th e C O mete r accordin g t o
th e mete r manufacturer' s instructions .
5 . Chec k idl e C O wit h th e headlights , heate r blower ,
rea r windo w defogger , coolin g fan , an d ai r condi -
tione r off .
NOTE : (Canada ) Pul l th e parkin g brak e leve r up .
Star t th e engine , the n chec k tha t th e headlight s ar e
off.
CO mete r shoul d indicat e 0.1 % maximum .
Inspection
any ope n flam e awa y fro m you r wor k area .
D
o no t smok e durin g thi s procedure . Kee p
ProCarManuals.com

Exhaust Gas Recirculation (EGR) System

The EGR system is designed to reduce oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the EGR

valve and the intake manifold into the combustion chambers. It is composed of the EGR valve, EGR vacuum control valve,

EGR control solenoid valve, ECM and various sensors.

The ECM contains memories for ideal EGR valve lifts for varying operating conditions. The EGR valve lift sensor detects

the amount of EGR valve lift and sends the information to the ECM. The ECM then compares it with the ideal EGR valve lift

which is determined by signals sent from the other sensors. If there is any difference between the two, the ECM varies cur-

rent to the EGR control solenoid valve to regulate vacuum applied to the EGR valve.

EGR

VALVE

LIFT

SENSOR
INTAKE

MANIFOLD

EGR

CONTROL

SOLENOID

VALVE
To No. 5 BACK-UP

LIGHTS ALTERNATOR

TURN SIGNALS

(15 A) FUSE

-EGR

VACUUM

CONTROL

VALVE

(cont'd)
EGR

VALVE

VARIOUS

SENSORSProCarManuals.com

Emission Control System

Positive Crankcase Ventilation (PCV) System

Description

The Positive Crankcase Ventilation (PCV) system is

designed to prevent blow-by gas from escaping to the

atmosphere. The PCV valve contains a spring-loaded

plunger. When the engine starts, the plunger in the PCV

valve is lifted in proportion to intake manifold vacuum

and the blow-by gas is drawn directly into the intake

manifold.

PCV HOSE
INTAKE MANIFOLD

PCV VALVE
Inspection

1. Check the PCV hoses and connections for leaks and

clogging.

BREATHER

PIPE

PCV VALVE

PCV HOSE

2. At idle, make sure there is a clicking sound from the

PCV valve when the hose between PCV valve and

intake manifold in lightly pinched with your fingers

or pliers.

Gently pinch here

If there is no clicking sound, check the PCV valve

grommet for cracks or damage. If the grommet is

OK, replace the PCV valve and recheck.
BLOW-BY VAPOR

FRESH AIR
BREATHER PIPEProCarManuals.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 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.

From No. 5 BACK-UP

LIGHTS ALTERNATOR

TURN SIGNALS (15 A)

FUSE

FUEL TANK

EVAP VALVE
EVAP

BYPASS

SOLENOID

VALVE
VARIOUS

SENSORS

EVAP CONTROL

CANISTER

VENT SHUT VALVE

FUEL

TANK

PRESSURE

SENSOR
EVAP

TWO WAY

VALVE
EVAP CONTROL

CANISTER
EVAP PURGE

CONTROL

SOLENOID VALVE

(cont'd)
FUEL FILL

CAPProCarManuals.com

BEARING OUTER RACE

75 mm THRUST SHIM

Selection.

CLAMP

BACK-UP LIGHT SWITCH

25 N-m (2.5 kgf-m, 18 Ibf-ft)

CLAMP

TRANSMISSION HANGER B

TRANSMISSION HANGER A

CLAMP

CLAMP

WASHER Replace.

OIL FILLER PLUG

44 N-m (4.5 kgf-m, 33 Ibf-ft)

42 x 63 x 12.5 mm OIL SEAL

Replace.

WASHER Replace.

DRAIN PLUG

39 N-m (4.0 kgf-m, 29 Ibf-ft)

36 mm SEALING BOLT

34 N-m (3.5 kgf-m, 25 Ibf-ft)

STRAINER COVER

O-RING Replace.
STRAINER SET SPRING

OIL PUMP STRAINER

14 mm SEALING BOLT

32 N-m (3.3 kgf-m, 24 Ibf-ft)

SPRING (L. 25 mm)

STEEL BALL (3/8 in)

REVERSE LOCKOUT SOLENOID

O-RING Replace.

SELECT LOCK PIN

SELECT LOCK RETURN SPRING

SELECT LOCK COLLAR

SPRING (L. 30 mm)
12 mm SEALING BOLT

22 N-m (2.2 kgf-m, 16 Ibf-ft)

STEEL BALL (5/16 in)

SHIFT LEVER ASSEMBLY

Removal, page 13-23

Installation, page 13-48

NEUTRAL POSITION SWITCH

25 N-m (2.5 kgf-m, 18 Ibf-ft)

TRANSMISSION HOUSING

OIL GUIDE PLATE

82 mm THRUST SHIM

Selection, page 13-46ProCarManuals.com

(cont'd)
Description

Gear Selection

Starting is possible only in positions through use of a slide-type, neutral-safety switch.

Automatic Transaxle (A/T) Gear Position Indicator

The A/T gear position indicator in the instrument panel shows what gear has been selected without having to look down

at the console.

With the shift lever in the position, the indicator light next to the in the instrument panel will display the gear

selected.

ATF Cooler

With this mid-engine type vehicle, the radiator is mounted at the front of the vehicle, so the ATF cooler is installed directly

on the transmission housing.
Rear wheels locked; parking pawl engaged with parking gear on countershaft.

All clutches released.

Reverse; reverse selector engaged with countershaft reverse gear and 4th clutch locked.

All clutches released.

General driving; starts off in 1st, shifts automatically to 2nd, 3rd, then 4th, depending on

vehicle speed and throttle position. Downshifts through 3rd, 2nd, and 1st on deceleration

to stop.

The lock-up mechanism comes into operation in 2nd, 3rd, and 4th gear.

Manual Shifting Driving; starts off 1st or 2nd, shifts to 2nd, 3rd, and 4th with the shift

switch operation.

Although, this position has an automatic shifting area:

• 1-2 upshift

• 4-3 downshift, 3-1 downshift, 2-1 downshift

depending on vehicle speed.

When the vehicle decelerates to a stop, the transmission shifts to 1st gear automatically.

The transmission can shift to 2nd gear by pushing the shift switch up while the vehicle is

stopped.

The lock-up mechanism comes into operation in 2nd, 3rd, and 4th gear.

Driving in 2nd gear; stays in 2nd gear, does not shift up and down.

For engine braking or better traction starting off on loose or slippery surface.

Driving in 1st gear, stays in 1st gear, does not shift up.

For engine braking.ProCarManuals.com

Partial Lock-up

Lock-up Control Solenoid Valve A: ON Lock-up Control Solenoid Valve B: OFF

The TCM switches solenoid valve A ON to release modulator pressure in the left cavity of the lock-up shift valve.

Modulator pressure in the right cavity of the lock-up shift valve overcomes the spring force, and the lock-up shift valve is

moved to the left side.

The torque converter pressure is separated into two passages:

Torque Converter Inner Pressure: enters into right side to engage lock-up clutch

Torque Converter Back Pressure: enters into left side to disengage lock-up clutch

Back pressure (F2) is regulated by the lock-up control valve, and the position of the lock-up timing valve B is determined

by throttle B pressure, tension of the valve spring, and pressure regulated by the modulator. Also, the position of the lock-

up control valve is determined by throttle valve B pressure, back pressure of the lock-up control valve, and torque converter

pressure regulated by the check valve. In low speed range, throttle B pressure working on the right side of the lock-up con-

trol valve is low, causing the valve to be moved to the right side. With the lock-up control solenoid valve B kept OFF, mod-

ulator pressure is maintained in the left end of the lock-up control valve; the lock-up control valve is moved slightly to the

left side. This slight movement of the lock-up control valve causes the back pressure to be lowered slightly, resulting in

partial lock-up.

NOTE: When used, "left" or "right" indicates direction on the hydraulic circuit.ProCarManuals.com