ACURA NSX 1997 Service Repair Manual

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Ignition Timin g Control :
Th e programme d ignitio n use d i n thi s engin e provide s optimu m contro l o f ignitio n timing . A microcompute r determine s
th e timin g i n respons e t o engin e spee d an d manifol d vacuu m pressure . Th e inpu t signal s ar e transmitte d b y th e crank -
shaf t position/cylinde r positio n (CKP/CYP ) sensor , throttl e positio n (TP ) sensor , EC T sensor , an d MA P sensor . Thi s sys -
tem , no t dependen t o n a governo r o r vacuu m diaphragm , i s capabl e o f settin g lea d angle s wit h complicate d characteristic s
whic h canno t b e provide d b y conventiona l governor s o r diaphragms .
Basi c Contro l
Determinatio n of ignitio n timing/curren t duration :
Th e EC M ha s store d withi n i t th e optimu m basi c ignitio n timin g fo r operatin g condition s base d upo n engin e spee d an d in -
tak e manifol d pressure . Wit h compensatio n b y signal s fro m sensors , th e syste m determine s optimu m timin g fo r ambien t
condition s an d send s voltag e pulse s t o th e ICM .
Compensatio n o f Ignitio n Timing :
Compensatio n Ite m
Idlin g
Compensatio n a t warm-u p
Engin e coolan t
temperatur e compensatio nRelate
d Senso r an d Informatio n
CKP/CY P sensor , MA P senso r
Engin e coolan t temperatur e
(ECT) senso r
ECT senso r Descriptio
n
Ignitio n timin g i s controlle d t o th e targe t spee d
wit h compensatio n accordin g t o th e idlin g speed .
La g angl e i s adjuste d accordin g t o warm-u p con -
dition s t o brin g abou t a goo d balanc e betwee n
operatin g performanc e an d exhaus t ga s level .
Compensatio n fo r lea d angl e a t low coolan t
temperatur e an d la g angl e a t hig h coolan t
temperature .
Contro l a t Star t
Ignitio n timin g is fixe d a t 5 ° BTD C fo r cranking . Th e crankin g is detecte d b y th e CY P senso r (crankin g rpm ) an d starte r signal .
Misfirin g Detectio n
A s par t o f th e OB D II misfirin g detectio n system , eac h o f th e ignitio n coil s ha s a built-i n spar k plu g voltag e sensor . Thi s
senso r detect s th e lon g duratio n hig h voltag e whic h occur s i n cas e o f unfavorabl e combustio n o r misfiring . (Fo r details ,
se e sectio n 11 .)
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Ignition Timin g Inspectio n
SRS component s ar e locate d in thi s area . Revie w th e SR S
componen t locations , precautions , an d procedure s i n th e
SR S (sectio n 24 ) befor e performin g repair s o r service .
1 . Pul l ou t th e servic e chec k connecto r locate d unde r
th e middl e o f th e dash . Connec t th e BL U an d BRN /
BL K terminal s wit h th e SC S servic e connector .
2 . Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
no loa d (A/ T i n o r position , M/ T i n neutral )
unti l th e radiato r fa n come s on , the n le t i t idle .
NOTE : I f yo u sto p th e engin e o r tur n th e ignitio n
switc h OF F afte r warm-u p wit h th e SC S servic e con -
necto r connected , th e engin e wil l idl e a t th e bas e
idl e speed . Tha t is , i t wil l no t b e controlle d b y th e
ECM . T o retur n t o th e norma l idl e speed , pres s th e
acclerato r peda l on e time .
SERVIC E CHEC K CONNECTO R (2P )
SC S SERVIC E CONNECTO R
07PAZ-001010 0
3. Chec k th e idl e spee d (se e pag e 23-92 ).
4 . Connec t a timin g ligh t t o th e servic e loop ; whil e th e
engin e idles , poin t th e ligh t towar d th e pointe r o n
the timin g bel t cover .
SERVIC E LOO P
TIMIN G LIGH T
5. Chec k th e ignitio n timin g wit h al l electrica l system s
ar e turne d OFF .
Ignitio n Timing : 15 ° ± 2° BTD C (RE D mark ) a t
Idl e Spee d (rpm) :
POINTE R
6. I f th e ignitio n timin g i s ou t o f spec , replac e th e ECM .
7 . Remov e th e SC S servic e connecto r fro m th e servic e
chec k connector .
CRANKSHAF T PULLE Y
RE
D MAR K
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Ignition Syste m
Idle Spee d Inspectio n
1. Star t th e engine . Hol d th e engin e a t 3,00 0 rp m wit h
no loa d (A/ T i n o r position , M/ T i n neutral )
unti l th e radiato r fa n come s on , the n le t i t idle .
2 . Connec t a tachomete r t o th e tes t tachomete r con -
nector .
TEST
TACHOMETE R
CONNECTO R
3. Chec k th e idl e spee d wit h al l electrica l system s
turne d OFF .
Idl e Spee d (rpm) :
4 . Adjus t th e idl e spee d if necessar y (se e sectio n 11 ).
Ignitio n Contro l Modul e (ICM )
Replacemen t
1. Disconnec t th e 8 P an d 6 P connector s fro m th e igni -
tio n contro l modul e (ICM) .
2. Remov e th e tw o mountin g bolts , an d slid e th e IC M
out towar d th e fron t side . B e carefu l no t t o damag e
th e vacuu m hose s whe n removin g th e ICM .
MOUNTIN G BOLT S12 N- m(1.2 kgf-m , 9 Ibf-ft )
6P CONNECTO R
8P CONNECTO R
G103
SERVIC E LOO P
JUMP STAR TTERMINA L
TESTTACHOMETE RCONNECTOR
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Ignition Contro l Modul e (ICM ) Inpu t Tes t
Disconnec t th e 8 P connecto r fro m th e ignitio n contro l
modul e (ICM) .
Inspec t th e connecto r an d socke t terminal s t o b e sur e
they ar e al l makin g goo d contact .
I f th e terminal s ar e bent , loose , o r corroded , repai r
them as necessary , an d rechec k th e system .
I f th e terminal s loo k OK , mak e th e followin g inpu t
test s a t th e connector .
— If an y tes t indicate s a problem , fin d an d correc t th e
cause , the n rechec k th e system .
— If al l th e inpu t test s prov e OK , th e IC M mus t b e faul -
ty ; replac e it .
IC M
NOTE :
The tachomete r shoul d operat e normally .
See sectio n 1 1 whe n th e malfunctio n indicato r
lamp (MIL ) blinks .
I f necessary , perfor m a n inpu t tes t o n th e IC M
afte r finishin g th e fundamenta l test s fo r th e igni -
tio n syste m an d fue l an d emissio n systems .
WHT/GRN
WHT1BLK1
WHT/BLK
View fro m termina l sid e
WHT/RE D
BLK2 WHT/YE L
8P CONNECTO R
No.Wir eTes t conditio n Test: Desire d resul t Possible caus e if resul t i s no t obtaine d
1
2
3
4
5
6
7
8
BLK1
BLK2
WHT1
WHT/GR N
WHT/BLK
WHT/BLU1
WHT/YE L
WHT/RE D
Under al l condition s
Ignition switc h "O N
(ID"
Chec k fo r continuit y t o ground :
Ther e shoul d b e continuity .
Chec k fo r voltag e t o ground :
Ther e shoul d b e batter y
voltage . •
Poo r groun d (G103 )
• A n ope n i n th e wir e
• Blow n No . 1 3 (3 0 A ) fus e i n th e
engin e compartmen t fuse/rela y
box
• Fault y ignitio n coi l
• A n ope n i n th e wir e
23-9 3
WHT/BLU1
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Ignition System

Ignition Coils/Spark Plugs Removal

CAUTION:

Ignition coils and spark plugs can become very hot in

use; do not touch them until the engine has cooled

down.

1. Remove the ignition coil covers.

2. Disconnect the 3P connectors from the ignition

coils.

3. Remove the ignition coils.

4. Remove the spark plugs.
NOTE: Different ignition coils and ignition coil

covers are used for the front and rear cylinders. Be

sure to use the correct ones when mounting them.

IGNITION COIL COVER

RUBBER

SEAL

PLATINUM TIP SPARK PLUG

CYLINDER HEAD

COVER
3P CONNECTOR

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Ignition Coi l Tes t
1. Wit h th e ignitio n switc h OFF , remov e th e ignitio n
coil.
2. Usin g a n ohmmeter , measur e resistanc e betwee n
th e terminals . Replac e th e coi l i f th e resistanc e i s
no t withi n specifications .
NOTE: Resistanc e wil l var y wit h th e coi l
temperature ; specificatio n i s a t 77° F (25°C) .
Primary Windin g Resistanc e
(Betwee n th e A an d B terminals) : 0.9 - 1. 1 ohm s
3. I f primar y windin g resistanc e i s OK , substitut e aknown-goo d ignitio n coil , an d chec k th e syste m
operation .
If th e syste m is normal , replac e th e origina l ignitio n
coil.
A TERMINA L
B TERMINA LIGNITIONCOIL
SECONDAR Y
WINDINGTERMINA L
SPARK PLU G
VOLTAG E
SENSO R
SECONDAR Y
WINDINGTERMINA L
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Ignition System

Spark Plug Inspection

1. Inspect the electrodes and ceramic insulator for:

Worn or deformed

electrodes

Cracked

insulator

Burned or worn electrodes may be caused by:

Advanced ignition timing

Loose spark plug

Plug heat range too hot

Insufficient cooling

Fouled plug may be caused by:

Retarded ignition timing

Oil in combustion chamber

Incorrect spark plug gap

Plug heat range too cold

Excessive idling/low speed running

Clogged air cleaner element

Deteriorated ignition coil
2. Replace the plug if it is fouled or worn. Do not use

spark plugs other than those listed below.

Spark Plug:

PFR6L-11 (NGK)

PK20PR-L11 (DENSO)

3. Make sure that the 1.3 mm (0.051 in) plug gauge

does not go into the gap for the platinum tip plug. If

the gauge goes into the gap, do not attempt to

adjust the side electrode; replace the plug with a

new
one.

Electrode Gap:

Platinum tip plug:

Check and confirm that the

1.3 mm (0.051 in) plug

gauge does not go into the

gap.

Anti-seize compound

applied to threads

4. Apply a small quantity of anti-seize compound to

the plug threads before installing each plug. Screw

the plugs into the cylinder head finger-tight, then

torque them to 18 N-m (1.8 kgf-m, 13 Ibf-ft).
Improper gap

Oil-fouling

Carbon deposits

Cracked center

electrode insulator
Damaged

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Noise Condenser Capacity Test

1. Use a commercially available condenser tester.

Connect the tester probes, and measure the con-

denser capacity.

Condenser capacity: 0.47 ±0.09 microfarads

POSITIVE TERMINAL

BODY GROUND

(Negative)

NOTE: The noise condenser is intended to reduce

ignition noise. However, condenser failure may

cause the engine to stop running.

2. If not within the specifications, replace the noise

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Charging Syste m
Componen t Locatio n Inde x
CHARGIN G SYSTE M LIGH T
(Buil t int o th e gaug e assembly )
Test, pag e 23-10 0
BATTER YTest, pag e 23-6 8
ALTERNATO R BEL T
Adjustment , pag e 23-10 9
ALTERNATO R• Alternato r an d Regulato r Test , pag e 23-10 2
• Replacement , pag e 23-10 5
• Overhaul , pag e 23-10 6
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Charging Syste m
Troubleshootin g
If th e chargin g syste m ligh t i s on , o r th e batter y i s dea d o r low , tes t th e followin g item s i n th e orde r listed :
1. Batter y (se e pag e 23-68 )
2 . Chargin g Syste m Ligh t
3 . Alternator/Regulato r
Charging Syste m Ligh t Tes t
Doe s th e chargin g syste m ligh t
com e on ?
Star t th e engine .
Does th e chargin g syste m ligh tgo off ?
Turn th e ignitio n switc h off .
Disconnec t th e 4 P connecto r
fro m th e alternator .
Turn th e ignitio n switc h O N (II) .
WHT/BL U wir e i s OK ; perfor m
alternator/regulato r tes t (se e pag e
23-102 ).
(T o page 23-101 )
Chargin g syste m ligh t circui t i s
OK .
Disconnec t th e AB S contro l uni t
(C235) , EP S contro l uni t (C249) ,
an d th e integrate d contro l uni t
(C401) , a s applicable . I f th e
chargin g syste m ligh t stay s on ,
repai r th e shor t t o groun d i n th e
WHT/BL U wire .
Does th e chargin g syste m ligh tcom e on ?
Tur
n th e ignitio n switc h O N (II) .
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