Page 305 of 1413
Intake Air System
System Description
The system supplies air for allengine needs. lt consists of the intake air pipe, Air Cleaner (ACL), intake air duct, Throttle
Body (TB), ldle Air Control {lAC) Valve, tast idle thermo valve, and intake manifold.
A resonator in the intake air pipe provides additional silencing as air is drawn into the system.
nacot{TRoLSOLENOIDVALVE
To
ffi -------------+ i'"ii'i''RELAY
VARIOUSSENSORS
IABCONTROLDIAPHRAGMVALVE
-BLK--L EI{GINE- cooLnnt
tFASTIDLETHERMOVALVE
U
INTAKEAIR PIPE
INTAKEAIRDUCT
11-116
Page 306 of 1413
Air Cleaner IACL)
ACL Element Rsplacoment
ACL HOUSINGCOVER
ACL ELEMENTClean air cleaner element everv15,OOO miles (24,OOO km) or 'l2 mon-ths and reDlace everv 3O,OOO miles(48,00O km) or 24 months under dus-ty conditions, rough or muddy roads.
AKE AIR OUCT
11-117
Page 307 of 1413

Intake Air System
Throttle cable [81881 enginel
1 1-1 18
Inspection/Adiustment
'I . Start the engine. Hold the engine at 3,000 rpm with
no load (A/T in $ or@ oosition, M/T in neutral) 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 1O-12 mm (O.39-O.47 in.)
DEFLECTION1O- 12 mm1O.39-0.47 in.l
4.lf deflection is not within specs, loosen the locknut
and turn the adjusting nut until the deflection is as
specifled.
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 throt-
tle valve to be sure it returns to the idle oosition
whenever you release the accelerator pedal.
Installation
1. Fully open the throttle valve. then install the throt-tle cable in the throttle linkage and install the cablehousing in the cable bracket.
2. Start the engine. Hold the engine at 3,OOO rpm withno load (A/T in S or @ position, M/T in neutrall untilthe radiator tan comes on, then let it idle.
THBOTTLE LII{KCABLEARACKET
i;
-l-r
,)
j
5.
LOCKNUTITINER CABLE
Hold the cable sheath, removing all slack from the
cable.
Turn the adjusting nut until it is 3 mm (O. 12 in.) away
trom the cable bracket.
Tighten the locknut. The cable deflection should now
be 10- 1 2 mm (O.39 -O.47 in.). lf not, see Inspec-
tion/Adjustment.
3 mm {0.12 in)
LOCKNUT1O N.m{1.O kgl.m,7 tbt.ft)
Page 308 of 1413

Throttle cable [B18C1 enginel
Inspection/Adiustment
1 . Start the engine. Hold the engine at 3,O0O lpm with
no load in neutral until the radiator fan comes on,
then let it idle.
2. Check that the throttl€ cable operates smoothly with
no binding or sticking. Repair as necessary.
3. Check csble free play at the throttle linkage, Cable
deflection should be 10-12 mm (O.39-O.47 in.)
DEFLECTIOI{10-12 mm(O.39-O.47 in.l
lf deflection is not within sDecs, loosen the locknut
and turn the adjusting nut until the deflection is as
specitied.
With the cable properly adjusted, check the throttle
valve to be sure it opens fully when you push the
accelerator Dedal to the tloor. Also check the throt-
tle valve to be sure it retums to the idle position
whenever vou release the accel€rator pedal.
CABLE BBACKET
ADJUSTING I{UT
lnstallation
1. Fullv open the throttle valve, then install the throt-
tle cable in the throttle linkage and install th€ cable
housing in the cable bracket.
2. Stan the engine. Hold the engine at 3,OOO rpm with
no load in neutral until the radiator fan comes on,
then let it idle.
THROTTLE LI K
With part A of the cabl€ bracket, support the cable
sheath so that there is no inner wire free play. Turn
the adjusting nut until it touches part A, leaving a
gap between the locknut and adiusting nul.
Move the cable sheath to psrt B of the cable brack-
et that so the bracket slides into the gap between
the locknut and adiusting nut. Tighten the locknul.
LOCKT{UTlO t{.m (t.O kgl.m, pART B
5.
4.
7 lbt.ftl{Locked by bracket)ADJUSTING NUT
PABT A
LOCKNUTNO GAP
AIUUSTINGNUT
5, The cable deflection should now be 10-12 mm
{O.39-O.47 in.). lf not, see Inspection/Adiustmsnt
11-119
Page 309 of 1413

lntake Air System
Throttle Body
Description
The throttle body is ot the single-barrel side-draft 1ype.
The lower portion of the throttle valve is heated by en-gine coolant from the cylinder head. The idle adjusting
screw which increases/dec.eases bvDass air and the
Evaporative Emission (EVAP) Control Canister port are
located on the top of the throttle body.
IOLE AOJUSTING
THROTTLESTOP SCREW(Non-adiustsb16l
11-120
Insoection
CAUTION: Do not adiust the thlottle stop screw. lt ispreset at the lactory.
1. Start the engine. Hold the engine at 3,OOO rpm with
no load (A/T in S or E position, M/T in neutral) until
the radiator fan comes on, then let it idle.
2. Disconnect the vacuum hose (to the EVAP control
canister) from the top of the throttle body; connect
a vacuum, gauge to the throttle body.
VACUUM PUMPGAUGEA973X-O41-XXXXX
5.
3. Allow the engine to idle and check that the gauge
indicates no vacuum.
a li there is vacuum, check the throttle cable (see
page 1 1-'l 18, 119).
Check that vacuum is indicated on the gauge when
the throttle is opened slightly from idle.
a lf the gauge indicates no vacuum, check the throt-
tle body port. lf the throttle body port is clogged.
clean it with carburetor cleaner.
Stop the engine and check that the throttle cable
operates smoothly without binding or sticking.
a lf there are any abnormalities in the above steps,
check for:
- Excessive wear or Dlav in the throttle valve shaft.
Sticky or binding throttle lever at full close po-
srtron.
Clearance between throttle stop screw and throt-
tle lever at tull close Dosition.
Page 310 of 1413
818B1 engino:
There should beno clearance.
THROTTLE STOP SCREW(Non-adiustablel
818Cl engine:
Replace the throttle body if there is excessive play in the
throttle valve shalt or if the shaft is binding or sticking.
THROTTLE LINK
(Non-adjusrablel
11-121
Page 311 of 1413
Intake Air System
Throttle Body (cont'dl
11-122
Dirarssmbly
GAUTION:
a Ths throttlo stop scrow is non-adrustablo.
a Aftar reassombly, adiust rhr throttlo Gablo (pago 11-118, 1 19). and A/T throttlo contlol cabl6 (section 14) for c!r8
rYith A/T.
a Tho TP sonaor ir not lomovablo
MAPSENSORTroubleshootingpage 11-52
TPSETSORTroubleshootingpoge 1l-60
O.BING
I
d^'%
IDLE ADJUSTINGSCREW
o-RtftGReplace.
FAST IDLETHERMOVALVEInspection, page 11-94
1O N.m11.O kgl.m.7 tbf.ftl
Page 312 of 1413
Intake Air Bypass (lABl Control System tBl8C1 enginel
Osscription
Two air intake paths are provided in the intake manifold to allow the selection of the intak€ path most favc
given engine speed.
Satisfactory power peformanc€ is achieved by closing and opening the intake air bypass (lAB) control valve!
que at low RPM is acheived when the valves are closed, whereas high power at high RPM is achieved by when
8re oDeneo.
IAB CONTROLVALVES
To PGM-FIMAIN RELi
IABCHECK VALVE
t favorabl€ for a
vslves. High tor-
when the valves
RELAY
(cont'dl
11-123