1995 ACURA TL engine

Fuel Suppl y Syste m
PGM-F I Mai n Rela y (cont'd )
Troubleshootin g Flowchar t
Engine wil l no t start .Inspectio n o f PGM-F I mai nrelay an d rela y harness .
Check fo r a n ope n in th e wir e (PG 1line) :1. Tur n th e ignitio n switc h OFF .
2 . Disconnec t th e PGM-F I mai n
rela y 4 P connecto r an d 8 P
connector .3. Chec k fo r continuit y betwee n
th e PGM-F I mai n rela y 8 P
connecto r termina l No . 7 an d
bod y ground . PGM-F
I MAI N RELA Y 8P CONNECTO R (C417 )
Wir e sid e o f femal e terminal s
I s ther e continuity ? Repai
r ope n in th e wir e betwee n
th e PGM-F I mai n rela y an d G10 1
(locate d a t righ t middl e o f
engine) .
Check fo r a n ope n o r shor t i n th e
wir e (BA T line) :
Measur e voltag e betwee n th e
PGM-F I mai n rela y 4 P connecto r
termina l No . 3 an d bod y ground . PGM-F
I MAI N RELA Y 4P CONNECTO R (C418 )
BAT(YEL /BLU)
Wire sid e o f femal e terminal s
I s ther e batter y voltage ? Repai
r ope n o r shor t i n th e
wir e betwee n th e PGM-F I
mai n rela y an d th e EC U (PCM )
(2 0 A ) fuse .
Replac e th e EC U (PCM ) (2 0 A )
fus e in th e under-hoo d fuse /
relay box .
Chec k fo r a n ope n o r shor t i n th e
wir e (IGS W line) :
1 . Tur n th e ignitio n switc h O N (II) .
2 . Measur e voltag e betwee n th e
PGM-F I mai n rela y 8 P connec -
to r termina l No . 5 an d bod y
ground .
Is ther e batter y voltage ?
(T o pag e 11-131 ) Repai
r ope n o r shor t i n th e
wir e betwee n th e PGM-F I
mai n rela y an d th e No . 2 FUE L
PUM P (1 5 A ) fuse .
Replac e th e No . 2 FUE L PUM P
(15 A ) fus e i n th e under-das hfuse/relay box .
ProCarManuals.com

Intake Air System

System Description

The system supplies air for all engine needs. It consists of the intake air pipe, Air Cleaner (ACL), intake air duct, Throttle

Body (TB), Idle Air Control (IAC) Valve, fast idle thermo valve, and intake manifold.

A resonator in the intake air pipe provides additional silencing as air is drawn into the system.

IAB LOW

CONTROL

SOLENOID

VALVE
IAB HIGH

CONTROL SOLENOID VALVE

IAB LOW

CONTROL

DIAPHRAGM

VALVE
From PGM-FI

MAIN RELAY

From No. 4 ECU

(PCM)
(15 A)

FUSE

(in the under-dash

fuse/relay box)

VARIOUS

SENSORS

INTAKE

AIR

DUCT

FAST

IDLE

THERMO

VALVE
IDLE

ADJUSTING

SCREW
ENGINE

COOLANT
INTAKE

MANIFOLD
PCM
IAB

VACUUM

TANK
IAB

CHECK

VALVE

IAB HIGH

CONTROL

DIAPHRAGM

VALVEProCarManuals.com

Throttle Cable

Inspection/Adjustment

1. Start the engine. Hold the engine at 3,000 rpm with

no load (transmission in or position) until the

radiator fan comes on, then let it idle.

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.)

ADJUSTING NUT

CABLE

BRACKET

DEFLECTION

10-12
mm

(0.39
-
0.47 in.)

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.

5. With the cable properly adjusted, check the throttle

valve to be sure it opens fully when you push the

accelerator pedal to the floor. Also check the throttle

valve to be sure it returns to the idle position whenev-

er you release the accelerator pedal.
Installation

1. Fully open the throttle valve, then install the throttle

cable in the throttle linkage and install the cable

housing in the cable bracket.

LOCKNUT
INNER CABLE

ADJUSTING

NUT

THROTTLE

LINKAGE

CABLE

BRACKET

2. Start the engine. Hold the engine at 3,000 rpm with

no load (transmission in or position) until the

radiator fan comes on, then let it idle.

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

cable.

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

from the cable bracket.

3 mm

(0.12 in.)

ADJUSTING

NUT
LOCKNUT

9.8 N-m

(1.0 kg-m,

7.2 Ibf-ft)

5.
CABLE

BRACKET

Tighten the locknut. The cable deflection should now

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

adjustment.
LOCKNUTProCarManuals.com

Intake Ai r Syste m
Throttl e Bod y
Descriptio n
The throttl e bod y i s a single-barre l side-draf t type . Th e
lowe r portio n o f th e throttl e valv e i s heate d b y engin e
coolan t fro m th e cylinde r head . Th e idl e adjustin g screw ,
whic h increases/decrease s bypas s air , an d th e Evapora -
tiv e Emissio n (EVAP ) Contro l Caniste r por t ar e locate d o n
the to p o f th e throttl e body .
THROTTL EPOSITION(TP)SENSO R
IDLE ADJUSTIN GSCREW
THROTTL E
VALV E
THROTTLE
STOPSCRE W
(non-adjustable )
Inspection
CAUTION : D o no t adjus t th e throttl e sto p screw . I t i s
prese t a t th e factory .
1 . Disconnec t th e vacuu m hos e (t o th e EVA P contro l
canister ) fro m th e to p o f th e throttl e body ; connec t
a vacuu m gaug e t o th e throttl e body .
2 . Star t th e engine . Hol d th e engine at 3,00 0 rp m wit h
no loa d (transmissio n i n ! o r position ) unti l th e
radiato r fa n come s on , the n le t i t idle .
VACUU M PUMP/GAUG EA973X - 04 1 - XXXX X
3. Allo w th e engin e t o idle , an d chec k tha t th e gaug e
indicate s n o vacuum .
If ther e i s vacuum , chec k th e throttl e cabl e (se e
pag e 11-135 ).
4 . Chec k tha t vacuu m is indicate d o n th e gaug e whe n
the throttl e is opene d slightl y fro m idle .
If th e gaug e indicate s n o vacuum , chec k th e throt -
tl e bod y port . I f th e throttl e bod y por t i s clogged ,
clea n i t wit h carbureto r cleaner .
5 . Sto p th e engine , an d chec k tha t th e throttl e cabl e
operates smoothly without bindin g o r sticking .
I f ther e ar e an y abnormalitie s i n th e abov e steps ,
check for .
— Excessiv e wea r o r pla y i n th e throttl e valv e shaft .
— Stick y o r bindin g throttl e leve r a t ful l close posi-
tion.
— Clearanc e betwee n throttl e sto p scre w an d throt -
tl e leve r a t ful l clos e position .
There shoul d b eno clearance .THROTTLE LEVE R
THROTTL ELEVER
THROTTL E STO P SCRE W(Non-adjustable )
Replace th e throttl e bod y i f ther e is excessiv e pla y i n th e
throttl e valv e shaf t o r i f th e shaf t i s bindin g o r sticking .
ProCarManuals.com

Emission Control System

Positive Crankcase Ventilation (PCV) System

Description

The Positive Crankcase Ventilation (PCV) system is

designed to prevent blow-by gas from escaping to the

atmosphere. The PCV valve contains a spring-loaded

plunger. When the engine starts, the plunger in the PCV

valve is lifted in proportion to intake manifold vacuum and

the blow-by gas is drawn directly into the intake manifold.

INTAKE

MANIFOLD
BREATHER PIPE

PCV HOSE

PCV VALVE

BLOW-BY VAPOR

FRESH AIR
Inspection

1. Check the PCV hoses and connections for leaks and

clogging.

PCV HOSE

BREATHER

PIPE

PCV VALVE

2.
At idle, make sure there is a clicking sound from the

PCV valve when the hose between the PCV valve

and intake manifold is lightly pinched with your fin-

gers or pliers.

Gently pinch here

If there is no clicking sound, check the PCV valve

grommet for cracks or damage. If the grommet is

OK, replace the PCV valve and recheck.ProCarManuals.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.

'96 model:
'97 - 98 models:

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.

'96 model:

INTAKE MANIFOLD
THROTTLE

BODY

EVAP PURGE

CONTROL

SOLENOID VALVE

FUEL TANK

EVAP VALVE
EVAP TWO WAY VALVE
From

No. 4 ECU
(PCM) (15A)

FUSE (in the under-dash

fuse/relay box)

EVAP

CONTROL

CANISTER FRESH

AIR
EVAP PURGE

FLOW SWITCH

FUEL FILL CAP
PCM
VARIOUS

SENSORS

FUEL TANK
ENGINE COOLANT TEMPERATURE ABOVE 158°F (70°C)
ENGINE COOLANT TEMPERATURE ABOVE 99°F (37°C)
EVAP PURGE CONTROL SOLENOID VALVE DUTY CON-

TROLLED AFTER STARTING ENGINE
EVAP PURGE CONTROL SOLENOID VALVE OFF AFTER

STARTING ENGINEProCarManuals.com

Description

The automatic transmission is a combination of a 3-element torque converter and a dual-shaft electronically controlled

automatic transmission which provides 4 speeds forward and 1 reverse. The entire unit is positioned in line with the engine.

Torque Converter, Gears and Clutches

The torque converter consists of a pump, turbine, and stator, assembled in a single unit. They are connected to the engine

crankshaft so they turn together as a unit as the engine turns. Around the outside of the drive plate is a ring gear which

meshes with the starter pinion when the engine is being started.

The entire torque converter assembly serves as a flywheel while transmitting power to the transmission mainshaft.

The transmission has two parallel shafts: the mainshaft and the countershaft. The mainshaft is in line with the engine

crankshaft. The mainshaft includes the 1st, 4th and 2nd clutches and gears for 4th, 1st, 2nd and reverse (3rd gear is integral

with the mainshaft). The countershaft includes the 3rd, 1st-hold and reverse clutches, and gears for 3rd, 4th, 1st, 2nd,

reverse and parking. The secondary drive gear is integrated with the countershaft. The gears on the mainshaft are in con-

stant mesh with those on the countershaft. When certain combinations of gears in the transmission are engaged by clutch-

positions.

and
es, power is transmitted from the mainshaft to the countershaft to provide

Electronic Control

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a linear solenoid and four solenoid

valves. Shifting and lock-up are electronically controlled for comfortable driving under all conditions.

The PCM is located below the dashboard, under the front lower panel on the passenger's side.

Hydraulic Control

The lower valve body assembly includes the main valve body, the secondary valve body, the throttle valve body, the lin-

ear solenoid, the shift control solenoid valves and the ATF passage body. They are bolted on the lower part of the trans-

mission housing. The regulator valve body, the ATF pump body, and the accumulator body are bolted to the torque con-

verter housing.

The main valve body on '96 model contains the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the

4-3 kick-down valve and the Clutch Pressure Control (CPC) valve. The main valve body on '97 model contains the manual

valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the 4-3 kick-down valve and the main orifice control valve.

The secondary valve body on '96 model contains the 3-4 orifice control valve, the 4-3 shift timing valve, the modulator valve

and the accumulator pistons.The secondary valve body on '97 model contains the 3-4 orifice control valve, the 4-3 shift tim-

ing valve, the line pressure control valve, the modulator valve and the accumulator pistons. The throttle valve body

includes the throttle valve which is bolted onto the secondary valve body. The linear solenoid is joined to the throttle valve

body. The regulator valve body contains the regulator valve, the lock-up shift valve and the cooler relief valve. Fluid from

the regulator passes through the manual valve to the various control valves. The ATF pump body contains the lock-up tim-

ing valve, the lock-up control valve and the relief valve. The torque converter check valve is located in the torque converter

housing under the ATF pump body. The accumulator body contains the accumulator pistons. The reverse accumulator and

the 1st-hold accumulator pistons are assembled in the rear cover.

The 1st, 1st-hold, 2nd and reverse clutches receive fluid from their respective feed pipes, and the 3rd and 4th clutches

receive fluid from the internal hydraulic circuit.

Shift Control Mechanism

Input from various sensors located throughout the vehicle determines which shift control solenoid valve the PCM will acti-

vate. Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes a

line to one of the clutches, engaging the clutch and its corresponding gear.

er through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes place, the

mainshaft rotates at the same speed as the engine crankshaft. Together with hydraulic control, the PCM optimizes the tim-

ing of the lock-up mechanism. The lock-up valves control the range of lock-up according to lock-up control solenoid valves

A and B, and throttle valve. When lock-up control solenoid valves A and B activate, modulator pressure changes. The lock-

up control solenoid valves A and B are mounted on the torque converter housing, and are controlled by the PCM.

(cont'd)
Lock-up Mechanism

In
position, in 2nd, 3rd, and 4th, and
position in 3rd, pressurized fluid is drained from the back of the torque convert-ProCarManuals.com

Position

The power flow when decelerating is as follows:

1. Rolling resistance from the road surface goes through the front wheels to the secondary drive gear, then to the counter-

shaft 1st gear via the 1st-hold clutch which is applied during deceleration.

2. The 1st gear one-way clutch disengages at this time because the application of torque is reversed.

3. The counterforce conveyed to the countershaft 1st gear turns the mainshaft 1st gear. At this time, since hydraulic pres-

sure is also applied to the 1st clutch, counterforce is also transmitted to the mainshaft. As a result, engine braking can

be obtained with 1st gear.

TORQUE CONVERTER

MAINSHAFT 1ST GEAR

MAINSHAFT

SECONDARY

DRIVER GEAR
COUNTERSHAFT

COUNTERSHAFT

1ST GEAR

SECONDARY DRIVEN GEAR

(cont'd)
1ST CLUTCH

1ST-HOLD

CLUTCHProCarManuals.com