6-4 Chapter 6 Emissions control systems
Blow-by
gas -
Fresh air -
Blow-by gas -
Fresh air ----
Rocker
P C V valve .
Carburetor
Carburetor
cover
Air clea(ler /
47r cleaner
/ Breather
011
separ2tor
Ventllat7on
hose
Intake
manifold
Ventilation
hose
I
_~
I
i
Applicable to U-engmes
2,la Typical Positive Crankcase Ventilation (PCV) system @.iJL engine on feft, 2.6L engine on right)
;Ippllcable to W-engines
manifold
2.4L Engine &r)L Engine
irnrake dir plenum
Air cleaner
A7r intake hose
i hrotile body
ii~r lrliake plenum
venuiat7on
‘:
2
_ Ventilation
hose
.e manrfold
hose
7
f
,Breather
hose
2.lb Typical Positive Crankcase Ventilation (PCV) system (24 engme on left, 3.OL engme on right)
2 Positive Crankcase Veniilation (PCV) system
i Evapnratwe emlssfons control system
Refer to i//ustrafions 2. la and 2. fb Hefer to dtustrabons d.za. 32, &% and 3.&i
1
A closed-type crankcase vennlatlon system IS uttllzed to prevent
1 io prevenr ~uei vapors 7rom escaping Into the atmosphere from the
blow-by gas6 from escaping into the atrhosphere. This sysrem has a tuel tank Idue to normal vaponzationj the vehicles in this manual
are
small orifice fixed at the intake mantiold or at the valve cover (see illustra- eqirtpped wim an evaporative emissions control system.
tions). : .Tne e’f;lpOra7IVtjet77lssionsconrrol system cpnsists of one or twova-
2 The blow-by gas is led through a rubber hose Tram the Wont ot the pomriqurd separators jnoi used 011 all models), an overfill limiter (two-way
valve cover into the a7r cleaner and through anotner hose tram the rear or valve). a tuel check valve. a purge control valve (carbureted
models)
or
the cover into the intake manirnld through tne onitce. H7 narrow ihrottle purge comroi soienolu valve (fuel-InJected models), a charcoal-fiiled can-
openings. the blow-by gas IS drawn from the rear ot
ihe
cover ~770 the In- ister ana lmes and hoses connecting the components (see illustrations).
take manifold with fresh air entennq rrom the air cleaner through the tront A caroon element, designed to store fuel vapors generated in the carbure-
of the valve cover. Ai wide open throttle. the blow-by gas IS drawn through torwhllettieengtne ISO~. ~s~nstalled~ntheaircleaneronsome models. No
both passages. routine ~~~~enanceis r~qu114, but If theelement appears to be clogged
3 Very little maintenance IS requlreu for the crankcase emission conitoi or dirty, i’splace 7t wtth a new one.
SjGtem. Check the hoses for
cracks
and kinks. Heplace them with new 3 The marcoal-tllled camster IS Installed between the fuel tank andthe
ones if they are deteriorated. Make sure mat tne oniice 7sn 7 clogged or air cieanrl Gasoline vapors are routed to ihis canister for temporary stor-
poor crankcase vent7latlon *wdl resul?.
age. While the engine IS runnrng, outside air is drawn through the canister,
,
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