fuel ACURA TL 1995 Service User Guide

Troubleshooting
Troubleshootin g Procedure s (cont'd )
Sympto m Char t
Liste d belo w ar e symptom s an d probabl e cause s fo r problem s tha t D O NO T caus e th e Malfunctio n Indicato r Lam p (MIL ) t o
com e on . I f th e MI L wa s reporte d on , g o to pag e 11-32 .
Troubleshoo t eac h probabl e caus e in th e orde r liste d (fro m lef t t o right ) unti l th e sympto m is eliminated .
Th e probabl e caus e an d troubleshootin g pag e referenc e ca n b e foun d below .
SYMPTO M
Engin e wil l no t star t
Har d startin g
Col d fas t idl e to o lo w
Col d fas t idl e to o hig h
Idl e spee d fluctuate s
Misfir e o r roug h runnin g
Lo w powe r
Engin e stall s
PROBABL E CAUS E
2, 3 , 21 , 13 , 1
2 , 10 , 12 , 20 , 2 1
5, 6 , 7 , 4
5 , 6 , 7 , 9 , 8
5 , 14 , 15 , 6 , 7 , 9 , 8
Troubleshoo t fo r misfir e o n page s 11-85 , 11-8 9
2, 8 , 9 , 11 , 18 , 17 , 19 , 1 0
2, 5 , 10 , 21 , 7 , 3 , 1 6
Othe r Probabl e Cause s fo r a n engin e tha t wil l no t start :
— Compressio n
— PGM-F I mai n rela y
— Engin e locke d u p
— Timin g bel t
Probabl e Caus e Lis t (for DTC chart see page 11-45).
—
Startin g syste m
— Ignitio n syste m
— Overheatin g
— Batter y
Probabl e Caus e
1
2
3
4
5
6
7
8
9
10
1 1
1 2
13
1 4
15
1 6
17
18
19
2 0
2 1
Pag e
11-5 3, 11-54
11-11 9
(See DTC chart)
(See DTC chart)
(See DTC chart)
11-113
11-11 4
11-136
11-13 5
(See DTC chart)
(See DTC chart)
(See DTC chart)
Sectio n 1 4
11-10 4
11-106
11-112
11-13 4
11-138
11-14 4
11-153
System
Powertrai n Contro l Modul e (PCM )
Fuel pressur e
Crankshaf t Position/Cylinde r Positio n senso r circui t
Intak e Ai r Temperatur e (IAT ) senso r circui t
Idl e Ai r Contro l (IAC ) Valv e
Fas t idl e therm o valv e
Idl e spee d adjustmen t
Throttl e bod y
Throttl e cabl e
Manifol d Absolut e Pressur e (MAP ) senso r
Throttl e Positio n (TP ) senso r
Barometri c pressur e (BARO ) senso r
A/ T gea r positio n signa l
Ai r Conditionin g Signa l
Alternato r F R Signa l
Brak e switc h signa l
Air Cleane r
Intake Ai r Bypas s (IAB ) contro l syste m an d intak e ai r duc t
Thre e Wa y Catalyti c Converte r (TWC )
Evaporativ e emissio n (EVAP ) contro l
Contaminate d fue l
ProCarManuals.com

Powertrain Contro l Modul e Dat a
B y connectin g th e OB D II sca n too l o r th e Hond a PG M Teste r t o th e 16 P dat a lin k connecto r (DLC) , variou s dat a ca n b e
retrieve d fro m th e PCM . Th e item s liste d in th e tabl e belo w confor m to th e SA E recommende d practice .
Th e Hond a PG M Teste r als o read s dat a beyon d tha t recommende d b y SAE .
Understandin g thi s dat a wil l hel p t o fin d th e cause s o f intermitten t failure s o r engin e problems .
NOTE:
The "operatin g values " give n belo w ar e approximat e value s an d ma y b e differen t dependin g o n th e environmen t an d
the individua l car .
Unles s note d otherwise , "a t idl e speed " mean s idlin g wit h th e engine completel y warme d up , transmissio n i n o r
position , an d th e A/ C an d al l accessorie s turne d off .
Dat aDescriptio nOperating Valu e
Freeze Dat a
Diagnosti c
Troubl e Cod e
(DTC )
If th e PC M detect s a problem , i t wil l stor e it a s a cod e
consistin g o f on e lette r an d fou r numbers .
Dependin g o n th e problem , a n SAE-define d cod e
(P0xxx ) o r a Honda-define d cod e (P1xxx ) wil l b e outpu t
t o th e tester . I
f n o proble m is detected ,
ther e i s n o output .
Engin e Spee d Th
e PC M compute s engin e spee d fro m th e signal s sen t
fro m th e Crankshaf t Positio n sensor .
Thi s dat a is use d fo r determinin g th e tim e an d amoun t
o f fue l injection . Nearl
y th e sam e a s
tachomete r indicatio n a t
idl e speed :
640 5 0 rp m
Vehicl e Spee d Th
e PC M convert s puls e signal s fro m th e Vehicl e
Spee d Senso r (VSS ) int o spee d data . Nearl
y th e sam e a s
speedomete r indicatio n
Manifol d
Absolut e
Pressur e (MAP )
The absolut e pressur e create d in th e intak e manifol d b y
engin e loa d an d speed . Wit
h engin e stopped :
Nearl y th e sam e a s atmo -
spheri c pressur e a t idl e
speed :
24-37 kP a (180-28 0
mmHg, 7.1-11. 0 inHg )
Engin e Coolan t
Temperatur e
(ECT)
The EC T senso r convert s coolan t temperatur e int o
voltag e an d signal s th e PCM . Th e senso r i s a thermisto r
whos e interna l resistanc e change s wit h coolan t
temperature . Th e PC M use s th e voltag e signal s fro m
th e EC T senso r t o determin e th e amoun t o f injecte d
fuel . Wit
h col d engine :
Sam e a s ambien t temper -
atur e an d IA T
Wit h engin e warme d up :
approx . 158-212° F
(70-100°C )
Heate d Oxyge n
Senso r (H02S )
(Bank 1, Sensor 1)
(Ban k 2 , Senso r 1 )
(Senso r 2 )
Th e Heate d Oxyge n Senso r detect s th e oxyge n conten t
i n th e exhaus t ga s an d send s voltag e signal s to th e
PCM . Base d o n thes e signals , th e PC M control s th e
air/fue l ratio . Whe n th e oxyge n conten t i s hig h (tha t is ,
whe n th e rati o is leane r tha n th e stoichiometri c ratio) ,
th e voltag e signa l i s lower . Whe n th e oxyge n conten t i s
lo w (tha t is , whe n th e rati o is riche r tha n th e stoichio -
metric ratio) , th e voltag e signa l i s higher .
0.0-1.2 5 V
A t idl e speed :
about 0.1-0. 9 V
O
(Senso r 1 )
ProCarManuals.com

Troubleshooting
Troubleshooting Procedure s (cont'd )
DataDescriptio nOperating Valu e
Freeze Dat a
HO2 S
Feedbac k
Loop Statu s
(Bank 1 : Right )
(Bank 2 : Left )
Loop statu s i s indicate d a s "open " o r "closed" .
Closed: Based o n th e HO2 S output , th e PC M deter -
mine s th e air/fue l rati o an d control s th e amoun t o f
injecte d fuel .
Open : Ignorin g H02 S output , th e PC M refer s t o signal s
fro m th e TP , MAP , an d EC T sensor s to contro l th e
amoun t o f injecte d fuel . A
t idl e speed : close d
Shor t Ter m
Fue l Tri m
(Ban k 1 : Right )
(Bank 2 : Left )
The air/fue l rati o correctio n coefficien t fo r correctin g
th e amoun t o f injecte d fue l whe n HO2 S feedbac k is in
th e close d loo p status . Whe n th e signa l fro m th e HO2 S
i s weak , shor t ter m fue l tri m get s higher , an d th e PC M
increase s th e amoun t o f injecte d fuel . Th e air/fue l rati o
graduall y get s richer , causin g a highe r HO2 S output .
Consequently , th e shor t ter m fue l tri m is lowered , an d
th e PC M reduce s th e amoun t o f injecte d fuel . Thi s
cycl e keep s th e air/fue l rati o close to th e stoichiometri c
rati o whe n in close d loo p status .-30%-+43 %
Long Ter m
Fue l Tri m
(Ban k 1 : Right )
(Ban k 2 : Left ) Lon
g ter m fue l tri m in compute d fro m shor t ter m fue l
tri m an d indicate s change s occurrin g in th e fue l suppl y
syste m ove r a lon g period .
If lon g ter m fue l tri m is highe r tha n 1.00 , th e amoun t o f
injecte d fue l mus t b e increased . I f i t i s lowe r tha n 1.00 ,
th e amoun t o f injecte d fue l mus t b e reduced .
-19%-+25 %
Intake Ai r
Temperatur e
(IAT)
The IA T senso r convert s intak e ai r temperatur e int o
voltag e an d signal s th e PCM . Whe n intak e ai r tempera -
tur e is low , th e interna l resistanc e o f th e senso r
increases , an d th e voltag e signa l i s higher . Wit
h col d engine :
Sam e a s ambien t temper -
atur e an d EC T
Throttl e
Positio n Base
d o n th e accelerato r peda l position , th e openin g
angl e o f th e throttl e valv e is indicated . A
t idle : Approx . 10 %
At ful l throttle : Approx .
90%
Ignitio n
Timing
The ignitio n advanc e angl e is se t b y th e PCM . Th e PC M
matche s ignitio n timin g t o th e drivin g conditions .A
t idl e speed : 1 5 + 2°
BTD C wit h th e SC S servic e
connecto r connected .
Calculated
Load Valu e
(CLV )
CLV is th e engin e loa d calculate d fro m th e MA P data . At idl e speed :
15-35 %
A t 2,50 0 rp m wit h n o load :
12-30 %
ProCarManuals.com

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 1,000 rpm.

Fuel cut-off action also takes place when engine speed exceeds 6,500 rpm, regardless of the position of the throttle

valve, to protect the engine from over-revving.

4. A/C Compressor Clutch Relay .

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

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

5. Evaporative Emission (EVAP) Purge Control Solenoid Valve

'96 model: When the engine coolant temperature is below 158°F (70°C), the PCM controls the EVAP purge control

solenoid valve which cuts vacuum to the EVAP purge control canister diaphragm.

'97 - 98 models: When the engine coolant temperature is above 99°F (37°C), the PCM controls the EVAP purge control

solenoid valve which controls vacuum to the EVAP purge control canister.

6. Intake Air Bypass (IAB) Low Control Solenoid Valve, Intake Air Bypass (IAB) High Control Solenoid Valve

When engine speed is below 3,350 rpm, the IAB High Control Solenoid Valve and IAB Low Control Solenoid Valve are

activated by a signal from the PCM. Intake air flows through a long chamber path, increasing torque at low RPM.

When engine speed is 3,350 - 3,950 rpm, the IAB Low Control Solenoid Valve is deactivated by the PCM. Intake air

flows through a short chamber path, increasing mid-range torque.

When the engine rpm is above 3,950 rpm, the IAB Low Control Solenoid Valve and IAB High Control Solenoid Valve are

deactivated by the PCM. This creates a very short intake path and increases high-speed torque.

7. Exhaust Gas Recirculation (EGR) Control Solenoid Valve

When the EGR is required for control of oxides of nitrogen (NOx) emissions, the PCM controls 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 PCM ignores that signal and assumes a pre-programmed

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

2. Back-up Function

When an abnormality occurs in the PCM 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 PCM supplies ground for the MIL and stores the DTC in

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

check the MIL bulb condition.

4. Two Driving Cycle Detection Method

To prevent false indications, the two driving cycle detection method is used for the H02S, fuel metering-related, idle

control system, ECT sensor, EGR system, TWC, EVAP control system and other self-diagnostic functions. When an

abnormality occurs, the PCM stores it in its memory. When the same abnormality recurs after the ignition switch is

turned OFF and ON (II) again, the PCM 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.ProCarManuals.com

Fuel Suppl y Syste m
Fuel Line s
NOTE : Chec k fue l syste m lines , hoses , filte r an d othe r component s fo r damage , leak s o r deterioration , an d replac e if nec -
essary .
22 N- m
'96 model : (2.2 kgf-m ,16 Ibf-ft )22 N- m(2.2 kgf-m ,16 Ibf-ft )
37 N- m(3.8 kgf-m , 2 7 Ibf-ft )
'97 - 9 8 models :
22 N- m(2.2 kgf-m , 1 6 Ibf-ft )
27 N- m(2.8 kgf-m , 2 0 Ibf-ft )
37 N- m(3.8 kgf-m , 2 7 Ibf-ft )
ProCarManuals.com

NOTE: Check all hose clamps and retighten if necessary.

'96 model:

To

FUEL

PRESSURE

REGULATOR
FUEL GAUGE SENDING

UNIT ASSEMBLY

FUEL

' FILTER
EVAPORATIVE EMISSION

(EVAP) TWO WAY VALVE

FUEL PUMP

ASSEMBLY

EVAPORATIVE EMISSION

(EVAP) CONTROL

CANISTER

10-15
mm

(0.39
-
0.59
in)
Clamp in the middle.

Clamp in the middle.
O-RING

Replace.

O-RING

Replace.

FUEL

TANKProCarManuals.com

Fuel Supply System

Fuel Lines (cont'd)

'97 - 98 models:

To

FUEL

PRESSURE

REGULATOR
FUEL

FILTER
FUEL GAUGE SENDING

UNIT ASSEMBLY
BASE GASKET

Replace.
FUEL PUMP

ASSEMBLY

EVAPORATIVE EMISSION

(EVAP) TWO WAY VALVE

EVAPORATIVE EMISSION

(EVAP) CONTROL

CANISTER

10- 15 mm

(0.39-0.59 in)
Clamp in the middle.

Clamp in the middle.
FUEL

TANKProCarManuals.com

Fuel Pressure
Relieving
Before disconnectin g fue l pipe s o r hoses , releas e pres -
sure fro m th e syste m b y loosenin g th e servic e bol t o n
top o f th e fue l rai l ('9 7 - 9 8 models : to p o f fue l filter) .
• D o no t smok e whil e workin g o n th e fue l system .
Kee p ope n flame s o r spark s awa y fro m you r wor k
area.
• B e sur e t o reliev e fue l pressur e whil e th e ignitio n
switc h is off .
1 . Mak e sur e yo u hav e th e anti-thef t cod e fo r th e radio ,
the n writ e dow n th e frequencie s fo r th e radio' s pre -
se t buttons .
2 . Disconnec t th e batter y negativ e cabl e fro m th e bat -
ter y negativ e terminal .
3 . Remov e th e fue l fil l cap .
4 . Us e a bo x en d wrenc h o n th e servic e bol t o n th e
fue l rai l ('9 7 model : o n th e fue l filter ) whil e holdin g
th e banj o bol t wit h anothe r wrench .
5 . Plac e a ra g o r sho p towe l ove r th e servic e bolt .
6 . Slowl y loose n th e servic e bol t on e complet e turn .
'9 6 model :
SERVIC EBOLT12 N- m(1.2 kgf-m , 8. 7 Ibf-ft )
FUE L RAI L SHO
P TOWE L
'97 - 9 8 models :
SERVICE BOL T12 N- m (1. 2 kgf-m ,8.7 Ibf-ft )
FUELFILTE R
SHOP
TOWE L
NOTE:
A fue l pressur e gaug e ca n b e attache d a t th e ser -
vic e bol t hole .
Alway s replac e th e washe r betwee n th e servic e
bol t an d th e banj o bol t wheneve r th e servic e bol t
i s loosened .
Replac e al l washer s wheneve r th e bolt s ar e
removed .
(cont'd)
ProCarManuals.com

Fuel Suppl y Syste m
Fuel Pressur e (cont'd )
Inspectio n
1 . Reliev e fue l pressur e (se e pag e 11-119 ).
2 . Remov e th e servic e bol t o n th e fue l rai l ('9 7 - 9 8
models : o n th e fue l filter ) whil e holdin g th e banj o
bol t wit h anothe r wrench . Attac h th e specia l tool .
'9 6 model :
FUEL
PRESSUR E
GAUG E
07406-004000 1
CLAMP
'97 - 9 8 models :
CLAMP
FUEL
PRESSUR E
REGULATO R
FUE L
PRESSUR E
GAUG E
07406-004000 1
FUEL FILTE R
3.
FUE L
PRESSUR E
REGULATO R
Start th e engine . Measur e th e fue l pressur e wit h th e
engin e idlin g an d th e vacuu m hos e o f th e fue l pres -
sur e regulato r disconnecte d fro m th e fue l pressur e
regulato r an d pinched . I f th e engin e wil l no t start , tur n
th e ignitio n switc h O N (II) , wai t fo r tw o seconds , tur n
i t OFF , the n bac k o n agai n an d rea d th e fue l pressure .
Pressur e shoul d be :
26 0 - 31 0 kP a (2.6 5 - 3.1 5 kgf/cm
2, 3 8 - 4 5 psi ) 4
. Reconnec t vacuu m hos e t o th e fue l pressur e regula -
tor.
Pressur e shoul d be :
19 0 - 24 0 kP a (1.9 4 - 2.4 5 kgf/cm2, 2 8 - 3 5 psi )
I f th e fue l pressur e is no t a s specified , firs t chec k th e
fue l pum p (se e pag e 11-128 ). I f th e fue l pum p is OK ,
chec k th e following :
I f th e fue l pressur e i s highe r tha n specified ,
inspec t for :
— Pinche d o r clogge d fue l retur n hos e o r line .
— Fault y fue l pressur e regulato r (se e pag e 11-124 ).
I f th e fue l pressur e i s lowe r tha n specified , inspec t
for:
— Clogge d fue l filter .
— Fault y fue l pressur e regulato r (se e pag e 11-124 ).
— Leakag e in th e fue l line .
ProCarManuals.com

Fuel Injector s
Replacemen t
Do no t smok e whe n workin g o n th e fue l system . 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 11-119 ).
2 . Remov e th e engin e cover .
3 . Disconnec t th e connector s fro m th e fue l injectors .
4 . Disconnec t th e vacuu m hos e an d fue l retur n hos e fro m th e fue l pressur e regulator .
NOTE : Plac e a ra g o r sho p towe l ove r th e hose s befor e disconnectin g them .
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 .
'96 model :
ENGINECOVER
O-RIN G
Replace .
CUSHIO NRINGReplace .
FUE L
INJECTO R
SEALRINGReplace .
HARNES S
HOLDE R
FUE L
RAIL S
PCVVALV E
12 N- m(1.2 kgf-m ,
8. 7 Ibf-ft )
22 N- m(2.2 kgf-m ,
1 6 Ibf-ft )
ProCarManuals.com