1991 MITSUBISHI MONTERO engine

Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
(1) - Refer to manufacturer's diagnostic trouble code procedure
and require repair or replacement of affected
component(s).
( 2) - Determine cause and correct prior to repair or replacement
of part.
( 3) - Determine source of contamination, such as engine
coolant, fuel, metal particles, or water. Require
repair or replacement.
( 4) - Inoperative includes intermittent operation or out of OEM
specification. Some components may be serviceable; check
for accepted cleaning procedure.









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CRUISE CONTROL BRAKE SWITCHES
See SWITCHES.
CRUISE CONTROL CABLES
See CRUISE CONTROL LINKAGES AND CABLES .
CRUISE CONTROL CLUTCH SWITCHES
See SWITCHES.
CRUISE CONTROL LINKAGES AND CABLES
CRUISE CONTROL LINKAGE AND CABLE INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Bent .................... A .. Require repair or replacement.
Binding ................. A .. Require repair or replacement.
Bracket bent, affecting
performance ............ A .. Require repair or replacement.
Bracket bent, not
affecting performance .. .. ........ No service suggested or
required.
Bracket broken, affecting
performance ............ A ............ Require replacement.
Bracket broken, not
affecting performance .. .. ........ No service suggested or
required.
Bracket corroded,
affecting performance .. A .. Require repair or replacement.
Bracket corroded, not
affecting performance .. 2 .. Suggest repair or replacement.

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B - E M IS SIO N A PPLIC ATIO N

1991 M it s u bis h i M onte ro
1990-91 ENGINE PERFORMANCE
Mitsubishi Emission Control Applications
Galant, Mirage, Montero, Pickup, Precis, Sigma,
Van/Wagon
EMISSION CONTROL DEVICE APPLICATIONS
EMISSION CONTROL DEVICE APPLICATIONS TABLE








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1.5L PFI Mirage
PCV, EVAP, TWC, EGR (1), SPK, O2, CEC, CE, EVAP-CS, EVAP-VC,
EGR-CS (1), EGR-TS (1), SPK-CC
1.5L PFI Precis
PCV, EVAP, TWC, EGR, SPK, O2, CEC, CE, EVAP-CS, EVAP-VC,
EGR-CS (1), EGR-TVS (2), SPK-CC
1.6L PFI
PCV, EVAP, TWC, EGR, SPK, O2, CEC, CE, EVAP-CS, EVAP-VC,
EGR-CS (1), EGR-TS (1), EGR-TVS (2), SPK-CC
1.8L, 2.0L & 2.0L Turbo PFI
PCV, EVAP, TWC, EGR, SPK, CEC, CE, EVAP-CS, EVAP-PV (3),
EVAP-VC, EGR-CS (1), EGR-TS (1), EGS-TVS, SPK-CC
2.4L PFI
PCV, EVAP, TWC, EGR, SPK, O2, CEC, CE, EVAP-CS, EVAP-VC,
EGR-CS (1)(4), EGR-TS (1), EGR-TVS (5), SPK-CC
2.6L 2-Bbl.
PCV, TAC, EVAP, TWC, EGR, SPK, PAS, O2, CEC, EVAP-CBVV,
EVAP-PV, EVAP-TV, EVAP-VC, EGR-VRV, SPK-TVS, PAS-PAV,
PAS-PAVCS, DVA
3.0L V6 PFI Montero
PCV, EVAP, TWC, SPK, O2, CEC, CE, EVAP-CS, EVAP-VC, SPK-CC
3.0L V6 PFI Pickup & Sigma
PCV, EVAP, TWC, EGR (1), SPK, O2, CEC, CE, EVAP-VC, EVAP-CS,
EGR-CS (1), EGR-TS (1), EGR-TVS (6), SPK-CC
3.0L SOHC, 3.0L DOHC & 3.0L Turbo (PFI) Stealth
PCV, EVAP, TWC, EGR, SPK, O2, CEC, CE, EGR-CSOLV (1),
EGR-TS (1), EGR-TV (2), PG-CSOLV, PG-CV (7), SPK-CC
(1) - California models only.
(2) - Federal models only.
(3) - Eclipse 2.0L Turbo models only.
(4) - Except Van/Wagon models.
(5) - Van/Wagon only.
(6) - Sigma Federal only.
(7) - Turbo models only.









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ABBREVIATION DEFINITIONS
ABBREVIATIONS DEFINITIONS TABLE








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Abbreviation Description
AIS ............................ Air Injection System
CBVV ..................... Carburetor Bowl Vent Valve
CE ............................... Check Engine Light
CEC ..................... Computerized Engine Control
EGR ....................... Exhaust Gas Recirculation
EGR-CS ......................... EGR Control Solenoid
EGR-TS ....................... EGR Temperature Sensor
EGR-TV .............................. EGR Thermovalve
EGR-TVS ................... EGR Thermal Vacuum Switch
EGR-VRV .................. EGR Vacuum Regulator Valve
EVAP ........................ Fuel Evaporation System
EVAP-CBVV ........... EVAP Carburetor Bowl Vent Valve
EVAP-CS ....................... EVAP Control Solenoid
EVAP-PV ............................ EVAP Purge Valve
EVAP-TV .......................... EVAP Thermal Valve
EVAP-VC ......................... EVAP Vapor Canister
FBC ............................. Feedback Carburetor
HAC ...................... High Altitude Compensation
HAC-VSV .................. HAC Vacuum Switching Valve
MCV ........................... Mixture Control Valve
O2 .................................... Oxygen Sensor
PAS ............................. Pulse Air Injection
PAS-PAV ......................... PAS Pulse Air Valve
PAS-PAVCS ............ PAS Air Valve Control Solenoid
PAV ................................. Pulse Air Valve
PAV-CSOLV ................ PAV Control Solenoid Valve
PCV .................. Positive Crankcase Ventilation
PFI ............................. Port Fuel Injection
PG-CSOLV ............... Purge Control Solenoid Valve
PG-CV .......................... Purge Control Valve
PG-TV ............................. Purge Thermovalve
SPK ................................... Spark Control
SPK-CC ...................... SPK Computer Controlled
SPK-TVS ................... SPK Thermal Vacuum Switch
TAC ........................ Thermostatic Air Cleaner
TWC .............................. Three-Way Catalyst









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EM IS SIO N C O NTR O L V IS U AL IN SPEC TIO N P R O CED URES

1991 M it s u bis h i M onte ro
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.

Single Diaphragm EGR Valve
This type uses a single diaphragm connected to the valve by a
shaft. Diaphragm is spring-loaded to keep valve closed in the absence
of vacuum. As throttle valves open and engine speed increases, vacuum
is applied to the EGR vacuum diaphragm, opening the EGR valve. This
vacuum signal comes from a ported vacuum source. Variations in the
vacuum signal control the amount of exhaust gas that is recirculated.
See Fig. 7 .
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
vacuum hose(s) to EGR valve is not plugged.
Fig. 7: Typical Single Diaphragm EGR Valve
Courtesy of General Motors Corp.
Dual Diaphragm EGR Valve
This type uses 2 diaphragms with different effective areas
and 2 vacuum sources. Although similar to the single diaphragm type,
the second diaphragm is added below the upper diaphragm and is rigidly
attached to the valve seat. See Fig. 8. These diaphragms form a vacuum
chamber which is connected to manifold vacuum.
During highway cruising when manifold vacuum is high in the
center chamber, manifold vacuum tends to pull the valve closed.
However, the vacuum signal applied to the top side of the upper
diaphragm overcomes the downward spring force and the manifold vacuum
pull, due to the diaphragm's larger piston. This regulates the amount
of EGR.
When manifold vacuum is low during acceleration, the higher
vacuum signal opens the valve, permitting more EGR. When manifold
vacuum is high during highway cruising, the valve is only partially
opened, reducing the amount of EGR.

Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
vacuum hose(s) to EGR valve is not plugged.
Fig. 8: Typical Dual Diaphragm EGR Valve
Courtesy of General Motors Corp.
Positive Backpressure EGR (BP/EGR) Valve
This type uses both engine vacuum and exhaust backpressure to
control the amount of EGR. It provides more recirculation during heavy
engine loads than the single diaphragm EGR valve.
A small diaphragm-controlled valve inside EGR valve acts as a
pressure regulator. The control valve gets an exhaust backpressure
signal through the hollow valve shaft. This exhaust backpressure
exerts a force on bottom of control valve diaphragm. The diaphragm
plate contains 6 bleed holes to bleed air into the vacuum chamber when
backpressure valve is in open position. See Fig. 9.
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed