Mitsubishi Montero (1998+). Manual - part 134

EMISSION CONTROL VISUAL INSPECTION PROCEDURES 

1998 Mitsubishi Montero

         1983-98 GENERAL INFORMATION

         Emission Control Visual Inspection Procedures

         All Models

         * PLEASE READ THIS FIRST *

         This article is provided for general information only. Not

all information applies to all makes and models. For more complete

information, see appropriate article(s) in the ENGINE PERFORMANCE

Section.

         EMISSION CONTROL LABELS

         The vehicle manufacturer’s emission control label, also known

as the underhood tune-up label or Vehicle’s Underhood Emission Control

System (VECI) label, is located in the engine compartment. Information

regarding year model of vehicle, engine size, number of cylinders,

emission equipment or type, engine tune-up specifications, whether

vehicle was manufactured for sale in California or is a Federal

vehicle, vacuum hose routing schematic, etc., can be found on this

label. See Fig. 1.

         In addition to the VECI label, some emission control

inspection and maintenance programs may require an additional label to

be affixed to the vehicle in special circumstances. For example, in

California, a Bureau Of Automotive Repair (BAR) engine label may be

affixed to the left door post. A BAR engine label is only used when

the vehicle has an engine change, approved modification or is a

Specially Constructed (SPCN) or an acceptable Gray market vehicle.

Check your state’s emission control inspection and maintenance laws to

determine if a similar label is used.

Fig. 1:  Typical Emission Control Label

Courtesy of General Motors Corp.

         EMISSION CONTROL VISUAL INSPECTION

         * PLEASE READ THIS FIRST *

NOTE:    The following emission control visual inspection procedures

         should be used as a guide only. When performing a visual

         inspection, always follow your state’s recommended

         inspection procedures.

         A visual inspection is made to determine if any required

emission control devices are missing, modified or disconnected.

Missing, modified or disconnected systems must be made fully

operational before a vehicle can be certified.

         POSITIVE CRANKCASE VENTILATION (PCV)

         PCV controls the flow of crankcase fumes into the intake

manifold while preventing gases and flames from traveling in the

opposite direction. PCV is either an open or closed system. See  Fig. 2

.

         Ensure PCV system is installed as required. Verify valve,

required hoses, connections, flame arresters, etc., are present,

routed properly and in serviceable condition.

Fig. 2:  Typical Open & Closed Type PCV System

         THERMOSTATIC AIR CLEANER (TAC)

         The TAC supplies warm air to air intake during cold engine

operation. This system is active during cold engine warm-up only.

Under all other operating conditions, air cleaner function is the same

as any non-thermostatic unit.

         Ensure required exhaust shroud, hot air duct, vacuum hoses

and air cleaner components are present and installed properly. See

Fig. 3. Ensure any required thermostatic vacuum switches are in place

and vacuum hoses are installed and in serviceable condition. Also

ensure air cleaner lid is installed right side up. Check for oversized

air filter elements and for additional holes in the air cleaner

housing.

Fig. 3:  Typical Thermostatic Air Cleaner System

         FUEL EVAPORATIVE SYSTEM (EVAP)

         The EVAP system allows for proper fuel system ventilation

while preventing fuel vapors from reaching the atmosphere. This means

that vapors must be caught and stored while the engine is off, which

is when most fuel evaporation occurs. When the engine is started,

these fuel vapors can be removed from storage and burned. In most

systems, storage is provided by an activated charcoal (or carbon)

canister. See Fig. 4. On a few early systems, charcoal canisters are

not used. Instead, fuel vapors are vented into the PCV system and

stored inside the crankcase.

         The main components of a fuel evaporation system are a sealed

fuel tank, a liquid-vapor separator and vent lines to a vapor-storing

canister filled with activated charcoal. The filler cap is normally

not vented to the atmosphere, but is fitted with a valve to allow both

pressure and vacuum relief.

         Although a few variations do exist between manufacturers,

basic operation is the same for all systems. Check for presence of

vapor storage canister or crankcase storage connections when required.

Ensure required hoses, solenoids, etc., are present and connected

properly. Check for proper type fuel tank cap. Check for any non-OEM

or auxiliary fuel tanks for compliance and the required number of

evaporation canisters.

Fig. 4:  Typical Fuel Evaporative System

         CATALYTIC CONVERTERS

         Oxidation Catalyst (OC)

         This type of converter is the most common. It may use pellets

or monolith medium, depending upon application. See  Fig. 5. Platinum

and palladium (or platinum alone) are used as catalyst in this type of

converter.

         Visually check for presence of catalytic converter(s). Check

for external damage such as severe dents, removed or damaged heat

shields, etc. Also check for pellets or pieces of converter in the

tailpipe.

Fig. 5:  Typical Oxidation Catalytic Converter (Pellet Type) Shown;

Typical Three-Way Catalytic Converter Is Similar

Courtesy of General Motors Corp.

         Three-Way Catalyst (TWC)

         This type of converter is nearly identical to a conventional