sensor ACURA NSX 1997 Service Owner's Guide

Drive B y Wir e Syste m
System Descriptio n
The Driv e B y Wir e Syste m is a n electroni c throttl e contro l system .
Thi s syste m consist s of the throttl e valv e contro l moto r an d Throttl e Positio n (TP ) senso r assemble d i n Throttl e Bod y (TB) ,
th e accelerato r positio n sensor , an d th e Engin e Contro l Modul e (ECM) .
Driv e B y Wir e Syste m Functions :
Idl e Contro l Functio n
Whe n th e engin e i s idling , th e EC M control s th e throttl e valv e contro l moto r t o maintai n th e prope r idl e spee d accordin g
t o engin e loads .
Acceleratio n Contro l Functio n
Whe n th e accelerato r peda l i s depressed , th e EC M open s th e throttl e valv e dependin g o n th e accelerato r positio n senso r
signals .
(cont'd)
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Drive By Wire System

System Description (cont'd)

Cruise Control Function

The ECM controls the throttle valve control motor to maintain the set speed when the cruise control system is operating.

The throttle valve control motor takes the place of the cruise control actuator.

Traction Control System (TCS) Function

If wheel spin occurs during acceleration or cornering, the TCS control unit requests the ECM to reduce the engine power

by retarding the ignition timing and closing the throttle valve. If the wheels lock during deceleration, the TCS control unit

signals the ECM to open the throttle valve.

Engine Protection Function

When the engine speed exceeds 8,000 rpm (M/T) or 7,500 rpm (A/T), the ECM controls the throttle valve, regardless of the

accelerator position, to protect the engine from over-revving.

Fail-safe Function

On this system, the ECM monitors the position of the accelerator pedal with a dual circuit type accelerator position sensor,

and monitors the operation of the throttle valve control motor with a Throttle Position (TP) sensor.

When an abnormality occurs in the system, the ECM restricts the operation of the throttle valve control motor to allow the

engine to continue to run.ProCarManuals.com

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 . Plac e a ra g o r sho p towe l ove r th e vacuu m hos e an d fue l retur n hose , the n disconnec t the m fro m th e fue l pres -
sur e regulator .
5 . Disconnec t th e fue l hos e fro m th e fue l rail .
6 . Remov e th e retaine r nut s fro m 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 .
INTAKEMANIFOL DCOVERS
12 N- m(1.2 kgf-m ,8.7 Ibf-ft )
FUELPRESSUR EREGULATO R
O-RINGReplace .
CUSHIO N
RIN G
Replace .
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 .
FUEL RAI L
HARNES SHOLDER
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13. To prevent damage to the O-rings, install the fuel injectors in the fuel rail first, then install them in the intake mani-

fold.

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 Ai r Syste m
System Descriptio n
The syste m supplie s ai r fo r al l engine needs. I t consist s o f th e intak e ai r pipe . Ai r Cleane r (ACL) , intak e ai r duct , throttl e
body , an d intak e manifold . A resonato r i n th e intak e ai r duc t provide s additiona l silencin g a s ai r i s draw n int o th e system .
IAB CONTRO L
SOLENOI D VALV E
To No . 5 BACK-U P LIGHT S
ALTERNATO R TUR N SIGNAL S
(1 5 A ) FUS E
IABCONTRO L
DIAPHRAG M
THROTTLE INTAK E
VALV E AI R DUC T
VARIOU SSENSOR S
ACL
IABCONTRO LVALVE
INTAK E
MANIFOL DRESONATO R
IABCHEC KVALV E
IABVACUU MTANK
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Intake Air System

Throttle Cable ———

Inspection/Adjustment

1. Remove the accelerator position sensor cover.

2. Check that the throttle cable operates smoothly with

no binding or sticking. Repair as necessary.

3. Check cable free play at the throttle linkage. Cable

deflection should be 10 - 12 mm (0.39 - 0.47 in.).

ACCELERATOR

POSITION

SENSOR COVER

DEFLECTION

10-12
mm

(0.39
-
0.47
in.
LOCKNUT

CABLE

BRACKET

ADJUSTING NUT

4. If deflection is not within specs, loosen the locknut,

turn the adjusting nut until the deflection is as spec-

ified then retighten the locknut.
Installation

1. Rotate the throttle linkage counterclockwise, then

install the throttle cable in the throttle linkage and

install the cable housing in the cable bracket.

THROTTLE LINKAGE

CABLE

BRACKET

INNER

WIRE

LOCKNUT
ADJUSTING

NUT

2. Hold the cable sheath, removing all slack from the

cable.

3. Turn the adjusting nut until it is 3 mm (0.12 in.)

away from the cable bracket.

4. Tighten the locknut. The cable deflection should now

be 10 - 12 mm (0.39 - 0.47 in.). If not, see inspection/

adjustment.

LOCKNUT

9.8 N-m

(1.0 kgf-m,

7.2 Ibf-ft)
ADJUSTING

NUT

CABLE

BRACKET

3 mm

(0.12 in.)ProCarManuals.com

Intake Air System

Throttle Body (cont'd)

Disassembly

THROTTLE BODY

IDLE ADJUSTING

SCREW

O-RING

Replace.

INTAKE AIR DUCT
THROTTLE VALVE

CONTROL MOTOR
TP SENSORProCarManuals.com

Intake Air System

Intake Air Bypass (IAB) Control System

Description

Satisfactory power performance is achieved by closing and opening the intake air bypass (IAB) control valves. High torque

at low engine speed is achieved when the valves are closed, whereas high power at high engine speed is achieved when

the valves are opened.

INTAKE AIR BYPASS (IAB) CONTROL

SOLENOID VALVE ON

ENGINE SPEED IS ABOVE 4,800 rpm

OPEN: HIGH ENGINE SPEED

CLOSED: LOW ENGINE SPEED

IAB CONTROL

SOLENOID

VALVE

To No. 5 BACK-UP LIGHTS

ALTERNATOR TURN SIGNALS

(15 A) FUSE

IAB

CONTROL

DIAPHRAGM

•IAB

CONTROL

VALVE
IAB

CHECK

VALVE

IAB

VACUUM

TANK
VARIOUS

SENSORSProCarManuals.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

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

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