1991 ACURA NSX fog light

Alternator (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 .
ECM CONNECTOR S
WIR E SID E O F FEMAL E TERMINAL S
Chec k fo r a shor t i n th e wire :
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 -
tor 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 approx . 5 V ?
Chec
k fo r a shor t i n th e circuit :
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 continuity ? Repai
r shor t i n th e wir e betwee nthe EC M (D5 ) and th e ALT .
Substitut e a known-goo d EC M
an d recheck . I f prescribe d voltag e
i s no w available , replac e th e origi -
nal ECM .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 GR N 4 P
connecto 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 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.
Doe s th e voltag e decreas e whe nhead light s an d rea r defogge r ar eturne d on ? AL
T F R signa l i s OK .
(T o pag e 11-120 )
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Idle Contro l Syste m
Idle Spee d Settin g
Inspection/Adjustmen t
NOTE: Befor e settin g th e idl e speed , chec k th e followin g
items :
— Th e Chec k Engin e ligh t ha s no t bee n reporte d on .
— Ignitio n timin g
— Spar k plug s
— Ai r cleane r
— PC V syste m
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 in position , M/ T in neutral ) unti l
th e radiato r fa n come s on , the n tur n th e ignitio n
switc h OFF .
2 . Connec t th e SC S servic e connecto r t o servic e chec k
connector .
3. Connec t a OBDI I sca n too l (se e pag e 11-38 ) o r
tachometer .
• Connec t a tachomete r t o loo p o f ignite r uni t sec -
ondary , or.. .
TACHOMETE R
Remove th e rubbe r ca p fro m th e tachomete r
connector an d connec t a tachometer .
TACHOMETE R
RUBBERCAP
TACHOMETE RCONNECTOR
4. Restar t th e engine .
5 . Chec k idlin g i n no-loa d condition s i n whic h th e
headlights , blowe r fan , rea r defogger , coolin g fan ,
an d ai r conditione r ar e no t operating .
NOTE : D o no t depres s th e accelerato r peda l i n thi s
step .
Idl e spee d shoul d be :
Adjus t th e idl e speed , i f necessary , b y turnin g th e
idl e adjustin g screw .
NOTE : Afte r adjustin g th e idl e spee d i n thi s step ,
chec k th e ignitio n timin g (se e sectio n 23 ).
I f i t i s ou t o f spec , g o bac k t o ste p 4 .
IDL E ADJUSTIN GSCREW
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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
Inspectio n
Do no t smok e durin g thi s procedure . Kee p
an y ope n flam e awa y fro m you r wor k area .
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 in position , M/ T in neutral ) unti l
the 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 11-128 ).
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 .
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Rear Windo w
Installatio n
18. Us e suctio n cup s t o hol d th e rea r windo w ove r th e
opening , alig n i t wit h th e alignmen t mark s mad e in
ste p 1 1 an d se t i t dow n o n th e adhesive . Lightl y
push o n th e rea r windo w unti l it s edge s ar e full y
seate d o n th e adhesiv e al l th e wa y around .
NOTE : D o no t clos e o r ope n th e door s unti l th e
adhesiv e is dry .
REA R WINDO W
ALIGNMEN TMARKS
19. Afte r th e adhesiv e is dry , spra y wate r ove r th e rea r
windo w an d chec k fo r leaks . Mar k leakin g area s
an d le t th e rea r windo w dry , the n sea l with sealant .
NOTE: Le t th e ca r stan d fo r a t leas t fou r hour s
after rea r windo w installation . I f th e ca r ha s t o b e
use d withi n th e firs t fou r hours , i t mus t b e drive n
slowly .
20. Connec t th e rea r defogge r sub-harnes s an d groun d
cable/antenn a lead , the n instal l th e grommets .
21 . Reinstal l al l remainin g remove d parts .
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Rear Window Defogger

Switch Replacement (cont'd)

5. Disconnect the 18-P and 10-P connectors.

CAUTION: Be careful not to damage the SRS wire

harness.

6. Remove the six screws, then remove the rear win-

dow defogger-light switch assembly.

10-P CONNECTOR

18-P CONNECTOR
REAR WINDOW DEFOGGER-

LIGHT SWITCH ASSEMBLY

7. If necessary, replace the rear window defogger

switch bulbs.

REAR WINDOW

DEFOGGER SWITCH

BULBS (0.91 W)ProCarManuals.com

Rear Window Defogger

Function Test

CAUTION: Be careful not to scratch or damage the

defogger wires with the tester probe.

1. Check for voltage between the positive terminal

and body ground with the ignition switch and the

defogger switch ON. There should be battery

voltage.

• If there is no voltage, check for:

— Faulty defogger relay.

— An open in the BLK/GRN wire.

• If there is battery voltage, go to step 2.

POSITIVE TERMINAL

NEGATIVE TERMINAL

2. Disconnect the positive terminal, check for con-

tinuity between the negative terminal and body

ground. If there is no continuity, check for an open

in the defogger ground wire.

3. Reconnect the positive terminal, touch the

voltmeter positive lead to the middle of each defog-

ger wire, and the negative lead to the negative ter-

minal. There should be approximately 6 V with the

ignition switch and the defogger switch ON.

• If the voltage is as specified, the defogger wire

is OK.

• If there is battery voltage, the defogger wire is

broken on the negative side.

• If there is no voltage, the defogger wire is

broken on the positive side.
Defogger Wires Repair

To make an effective repair, the broken section must be

no longer than one inch.

1. Lightly scrub the area around the break with fine

steel wool, then clean it with alcohol.

2. Carefully mask above and below the broken section

with cellophane tape.

OPEN

CELLOPHANE

TAPE

DEFOGGER WIRE

3. Using a small brush, apply a heavy coat of silver

conductive paint extending about 1/8" on both

sides of the break. Thoroughly mix the paint before

use. Let it dry for thirty minutes.

PAINT

4. Check for proper operation with a voltmeter (it

should read half of battery voltage at the mid-

point).

5. Apply a second coat of paint in the same way. Let it

dry for three hours before removing the tape.ProCarManuals.com

Idle Control System
Troubleshooting Flowchart

Alternator (ALT) FR Signal
This signals the ECM when the alternator is charging.
Inspection of ALT FR signal.
Connect the test harness be-
tween the ECM and connector.
Disconnect "D" connector from
the engine wire harness only, not
the ECM (see page 11-37).

Turn the ignition switch ON.

Measure voltage between D9 ( + ) terminal and A26 (-) ter-
minal.
Is there approx. 5 V?
Turn the ignition switch OFF.
Reconnect "D" connector to the
engine wire harness.
Warm up engine to normal oper-ating temperature (the cooling
fan comes on).
Measure voltage between D9( + ) terminal and A26 (-) ter-
minal.

Does the voltage decrease when

headlights and rear defogger are

turned on ?

Do the ECM Reset Procedure
(see page 11-35).
ALT FR signal is OK.(To page 11-93) Substitute a known-good ECM

and recheck. If prescribed

voltage is now available, replace
the original ECM.
Turn the ignition switch OFF.ProCarManuals.com

Idle Control System
Idle Speed Setting
Inspection/Adjustment NOTE: (Canada) Pull the parking brake lever up.
Start the engine, then check that the head lights

are
off.
1. Start the engine and warm it up to normal operating temperature (the cooling fan comes on).
2. Connect a tachometer. Connect a tachometer to loop of ICM second-
ary, or...
TACHOMETER

ICM

Remove the rubber cap from the tachometer
connector and connect a tachometer.
TACHOMETER
TACHOMETER CONNECTOR
RUBBER

CAP
3. Disconnect the 2P connector from the IAC valve.
IAC VALVE
4. Start the engine with the accelerator pedal slightly depressed, then turn the headlights and rear defog-
ger ON. After the MIL comes on, stabilize the

engine speed at 1000 rpm, then slowly release the

pedal until the engine idles.

If the engine stalls, turn the idle adjusting screw
one turn counterclockwise and recheck.
5. Check idling with the headlights and rear defogger
on.

Idle speed should be:
M/T
A/T
550 ± 50 rpm
550 ± 50 rpm (in or range)
Adjust the idle speed, if necessary, by turning
the idle adjusting screw.
If the proper idle speed cannot be achieved,
clean the throttle body port with carburetor
cleaner.

IDLE ADJUSTING

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