1997 ACURA NSX turn signal

PGM-FI Syste m
System Descriptio n
INPUTSENGIN E CONTRO L MODUL E (ECM )OUTPUT S
Front Primar y H02 S
Rea r Primar y HO2 S
Fron t Secondar y HO2 S
Rea r Secondar y H02 S
MA P Senso r
CKP/CY P Senso rECT Senso rTP Senso rAP Senso rIAT Senso rVSSFron t K SRea r K SEG R Valv e Lif t Senso rA/TFI Signal sTCS Signal s
Spar k Plu g Voltag e
Detectio n Modul e Signa l
Starte r Signa l
Brak e Switc h Signa l
AL T F R Signa l
Ai r Conditionin g Signa l
A/ T Gea r Positio n Switc h Signa l
Neutra l Switc h Signa l (M/T )
Clutc h Switc h Signa l (M/T )
VTE C Pressur e Switc h
Batter y Voltag e (IGN . 1 )
Fue l Tan k Pressur e Senso r
Cruis e Contro l Mai n Switc h Signa l
Se t Switc h Signa l
Resum e Switc h Signa l Fue
l Injector s
PGM-F I M.ai n Rela y (Fue l Pump )
Malfunctio n Indicato r Lam p
Throttl e Valv e Contro l Moto r
A/ C Compresso r Clutc h Rela y
ICMEVA P Purg e Contro l Solenoi d Valv e
EVA P Bypas s Solenoi d Valv e
EVA P Contro l Caniste r
Ven t Shu t Valv e
Fue l Pum p Rela y
EG R Contro l Solenoi d Valv e
IA B Contro l Solenoi d Valv e
VTE C Solenoi d Valve s
Fron t Primar y H02 S Heate r
Rea r Primar y H02 S Heate r
Fron t Secondar y H02 S Heate r
Rea r Secondar y H02 S Heate r
Cruis e Contro l Indicato r Ligh t
Revers e Lockou t Rela y
DLC
PGM-F I Syste m
Th e PGM-F I syste m o n thi s mode l i s a sequentia l multipor t fue l injectio n system .
Fue l Injecto r Timin g an d Duratio n
Th e EC M contain s memorie s fo r th e basi c discharg e duration s a t variou s engin e speed s an d manifol d pressures . Th e
basi c discharg e duration , afte r bein g rea d ou t fro m th e memory , i s furthe r modifie d b y signal s sen t fro m variou s sensor s
t o obtai n th e fina l discharg e duration .
Throttl e Valv e Contro l
Th e EC M control s th e throttl e valv e contro l moto r base d o n accelerato r peda l position , TC S contro l uni t signals , an d vari -
ou s othe r signals . Th e EC M als o control s th e idl e contro l function , cruis e contro l function , an d othe r function s wit h th e
throttl e valv e control .
Ignitio n Timin g Contro l
Th e EC M contain s memorie s fo r basi c ignitio n timin g a t variou s engin e speed s an d manifol d pressures . Ignitio n timin g
i s als o adjuste d fo r engin e coolan t temperature .
A knoc k contro l syste m is als o used . Whe n detonatio n i s detecte d b y th e knoc k senso r (KS) , th e ignitio n timin g i s
retarded .
Other Contro l Function s
1 . Startin g Contro l
Whe n th e engin e is started , th e EC M provide s a ric h mixtur e b y increasin g fue l injecto r duration .
2 . Fue l Pum p Contro l
Whe n th e ignitio n switc h i s initiall y turne d o n (II) , th e EC M supplie s groun d t o th e PGM-F I mai n rela y tha t supplie s
curren t t o th e fue l pum p fo r tw o second s t o pressuriz e th e fue l system .
Whe n th e engin e is running , th e EC M supplie s groun d to th e PGM-F I mai n rela y tha t supplie s curren t t o th e fue l pump .
Whe n th e engin e i s no t runnin g an d th e ignitio n i s on , th e EC M cut s groun d t o th e PGM-F I mai n rela y whic h cut s
curren t t o th e fue l pump .
Excellen t engin e performanc e is achieve d throug h th e us e o f VTE C (Variabl e Valv e Timin g an d Valv e Lif t Electroni c
Contro l System) , intak e ai r bypas s contro l an d discharg e volum e contro l o f th e fue l pump .
(cont'd )
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PGM-FI System

System Description (cont'd)

3. Fuel Cut-off Control

During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy at

speeds over 1,500 rpm.

Fuel cut-off action also takes place when engine speed exceeds 8,300 rpm, regardless of the position of the throttle

valve, to protect the engine from over-revving.

4. A/C Compressor Clutch Relay

When the ECM receives a demand for cooling from the air conditioning system, it delays the compressor from being

energized, and enriches the mixture to assure smooth translation to the A/C mode.

5. Evaporative Emission (EVAP) Purge Control Solenoid Valve

When the engine coolant temperature is below 153°F (67°C), the ECM controls the EVAP purge control solenoid valve

which cuts vacuum to the EVAP purge control canister diaphragm.

6. Intake Air Bypass (IAB) Control Solenoid Valve

When the engine speed is below 4,800 rpm, the IAB control solenoid valve is activated by a signal from the ECM. Intake

air then flows through the smaller chamber, and high torque is delivered. To increase air flow at engine speeds higher

than 4,800 rpm, the solenoid valve is deactivated by the ECM, and the intake air flows through the larger chamber.

7. Exhaust Gas Recirculation (EGR) Control Solenoid Valve

When the EGR is required for control of oxides of nitrogen (NOx) emissions, the ECM supplies ground to the EGR

control solenoid valve which supplies regulated vacuum to the EGR valve.

ECM Fail-safe/Back-up Functions

1. Fail-Safe Function

When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-programmed

valve for that sensor that allows the engine to continue to run.

2. Back-up Function

When an abnormality occurs in the ECM itself, the fuel injectors are controlled by a back-up circuit independent of the

system in order to permit minimal driving.

3. Self-diagnosis Function [Malfunction Indicator Lamp (MIL)]

When an abnormality occurs in a signal from a sensor, the ECM lights the MIL and stores the diagnostic trouble code

in erasable memory. When the ignition is initially turned on, the ECM supplies ground for the MIL for two seconds to

check the MIL bulb condition.

4. Two Trip Detection Method

To prevent false indications, the Two Trip Detection Method is used for the H02S, fuel metering-related, idle control

system, ECT sensor, EGR system self-diagnostic functions and EVAP control system. When an abnormality occurs,

the ECM stores it in its memory. When the same abnormality recurs after the ignition switch is turned OFF and ON (II)

again, the ECM informs the driver by lighting the MIL.

However, to ease troubleshooting, this function is cancelled when you short the service check connector. The MIL will

then blink immediately when an abnormality occurs.

5. Two (or three) Driving Cycle Detection Method

A "Driving Cycle" consists of starting the engine, beginning closed loop operation, and stopping the engine. If misfir-

ing that increases emissions or EVAP control system malfunction is detected during two consecutive driving cycles,

or TWC deterioration is detected during three consecutive driving cycles, the ECM turns the MIL on.

However,
to
ease
troubleshooting,
this
function
is
cancelled when
you
short
the
service check connector.
The MIL
will

then blink immediately when an abnormality occurs.ProCarManuals.com

Engine Contro l Modul e (ECM )
NOTE: I f thi s sympto m is intermittent , chec k fo r a loos e No . 5 BACK-U P LIGHTS , ALTERNATOR ,
TUR N SIGNAL S (1 5 A ) fus e in th e under-das h fuse/rela y box , a poo r connectio n a t EC M termina l
A7 , o r a n intermitten t ope n in th e BL U wir e betwee n th e EC M (A7 ) an d th e gaug e assembly .
I s th e lo w oi l pressur e ligh t on ?
Tr y t o star t th e engine .
Doe s th e engin e start ?
Chec k fo r a n ope n in th e wir e o r
bulb :
1. Tur n th e ignitio n switc h OFF .2. Connec t th e EC M connecto r
termina l A 7 t o bod y groun d
with a jumpe r wire .3. Tur n th e ignitio n switc h O N (II) .
Is th e MI L on ?
Substitut e a known-goo d ECM ,
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
the origina l ECM .
— Repai r shor t i n the wir e
betwee n No . 5 BACK-U P
LIGHTS , ALTERNATOR , TUR N
SIGNAL S (1 5 A ) fus e an d
gaug e assembly .
— Replac e No . 5 BACK-U P
LIGHTS , ALTERNATOR , TUR N
SIGNALS (15 A) fuse.
Chec k fo r a n ope n in th e wire s
(PG lines) :1. Tur n th e ignitio n switc h O N (II) .
2 . Measur e voltag e betwee n
bod y groun d an d EC M con -
necto r terminal s A1 2 an d A2 5
individually .
I s ther e les s tha n 1. 0 V ?
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 . Repai
r ope n i n th e wire(s )
betwee n EC M an d G10 1 (locate d
a t intak e manifold ) tha t ha d
mor e tha n 1.0V .
— Repai r ope n i n th e wire s
betwee n EC M (A7 ) an d gaug e
assembly .— Replac e th e MI L bulb .
(cont'd )
Turn th e ignitio n switc h O N (II) .
The Malfunctio n Indicato r Lam p
(MIL ) neve r come s o n (eve n fo r
tw o seconds ) afte r ignitio n i s
turne d O N (II) .
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Idle Contro l Syste m
Alternato r (ALT ) F R Signa l
This signal s th e EC M whe n th e Alternato r (ALT ) i s charging .
Inspection o f AL T F R Signal .
Chec k fo r a shor t i n th e wir e
(ALT F line) :
1 . Disconnec t th e GR N 4 P con -
necto r fro m th e ALT .
2 . Tur n th e ignitio n switc h O N (II) .
3 . Measur e voltag e betwee n EC M
connecto r terminal s D 5 an d
A26.
Is ther e approx . 5 V ?
Chec k th e operatio n o f th e ALT :
1. Tur n th e ignitio n switc h OFF .2. Reconnec t th e AL T GRI M 4 Pconnecto r t o th e ALT .
3 . Star t th e engine . Hol d th e
engin e a t 3,00 0 rp m wit h n oloa 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 .
4 . Measur e voltag e betwee n EC M
connecto r terminal s D 5 an d
A26 .
I
Doe s th e voltag e decreas e whe n
headlight s an d rea r defogge r ar e
turne d on ?
(T o pag e 11-121 ) Chec
k fo r a shor t i n th e wir e
(ALT F line) :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e negativ e bat -
ter y cabl e fro m th e battery .
3 . Disconnec t th e EC M connec -
to r D (22P ) fro m th e ECM .
4 . Chec k fo r continuit y betwee n
EC M connecto r termina l D 5
an d bod y ground .
I s ther e continuity ? Repai
r shor t i n th e wir e betwee n
the EC M (D5 ) and th e ALT .
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 pre -
scribe d voltag e is no w available ,
replac e th e origina l ECM .
AL T F R signa l i s OK .
ProCarManuals.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

CAPProCarManuals.com

Description

At a vehicle speed of 19 mph (30 km/h) or more, a signal from the vehicle speed sensor (VSS) activates the reverse lockout

solenoid, which causes the select lock pin to extend. As a result, the interlock cannot rotate to the reverse shift piece mak-

ing it impossible to select reverse gear.

At a vehicle speed of 16 mph (25 km/h) or less, the signal from the VSS is interrupted which turns off the reverse lockout

solenoid. The select lock return spring pulls the select lock pin back, enabling the interlock to move freely so that reverse

gear can be selected.ProCarManuals.com