Chapter 6 Emissions control systems 6-3
FRONT
1.3~ Vacuum schematic (1990 and later 2.4L engines)
1 General information
Refer to illustrations 1.3a, 1.36, 1.312, 1.3d and 1.3e
To prevent pollution of the atmosphere from incompletely burned and
evaporating gases, and to maintain good driveability and fuel economy,
a number of emission control systems are incorporated. The principal sys-
tems are:
Air aspirator system
Catalytic converter
Deceleration system
Evaporative emission control system
Exhaust Gas Recirculation (EGR) system
Feedback carburetor (FBC) system
Heated air intake system
Jet air system
Multi-Port injection (MPI) system
Oxygen sensor
Positive Crankcase Ventilation (PCV) system
Secondary Air Supply (SAS) system
The Sections in this Chapter include general descriptions, checking
procedures within the scope of the home mechanic and component re-
placement procedures (when possible) for each of the systems listed
above.
Before assuming an emissions control system is malfunctioning,
check the fuel and ignition systems carefully. The diagnosis of some emis-
sion control devices requires specialized tools, equipment and training. if
checking and servicing become too difficult or if a procedure is beyond
yourability, consuitadealerservicedepartment. Remember, themostfre-
quent cause of emissions problems is simply a loose or broken vacuum
hose or wire, so always check the hose and wiring connections first (see
illustrations).
This doesn’t mean, however, that emission control systems are partic-
ularly difficult to maintain and repair. You can quickly and easily perform
many checks and do most of the regular maintenance at home with com-
mon tune-up and hand tools. Note:
Because ofa Federailymandatedex-
tended warranty which covers the emission controlsystem components,
check with your dealer about warranty coverage before working on any
emissions-relatedsystems. Once the warranty
has
expired, you may
wish
to perform some of the component checks and/or replacement proce-
dures in this Chapter to save money
Pay close attention to any special precautions outlined in this Chapter.
it should be noted that the illustrations of the various systems may not ex-
actly match the system installed on your vehicle because of $hanges
made by the manufacturer during production or from year-to-year.
A Vehicle Emissions Control information label is located in the engine
compartment (usually on the underside of the hood). This label contains
important emissions specifications and adjustment information. When
servicing the engine or emissions systems, the VECI label in your particu-
lar vehicle should always be checked for up-to-date information.
Fuel ~ressura
FRONT
purge control
solenoid valve
B : Black
G : Green
- -~
L : Light Blue
-
R : Red
Y : Yellow
1.3d Vacuum schematic (1990 and later Federal and Canadian
3.OL engines)
B : Black
G : Green
L : Light Blue
R : Red
Y : Yeilow
Fuel pressure
regulator
EGR valve
Canjster
Throttle body
solenoid valve
FRONT
EGR dontroi
solenoid valve
1.3e Vacuum schematic (1990 and later California 3.OL engines)
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