catalytic converter MITSUBISHI MONTERO 1998 Service Manual









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ABBREVIATION DEFINITION 










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B/P Backpressure 

BAC By-Pass Air Control 

BAP Barometric Absolute Pressure Sensor 

BARO Barometric 

BBDC Before Bottom Dead Center 

BCM Body Control Module 

BDC Bottom Dead Center 

BHP Brake Horsepower 

BLK Black 

BLU Blue 

BMAP Barometric & Manifold Absolute Pressure Sensor 

BOO Brake On-Off Switch 

BP Barometric Pressure sensor 

BPS Barometric Pressure Sensor 

BPT Backpressure Transducer 

BRN Brown 

BTDC Before Top Dead Center 

BTU British Thermal Unit 

BVSV Bimetallic Vacuum Switching Valve 

Baro. Barometric 

Batt. Battery 

Bbl. Barrel (Example: 4-Bbl.) 

Blst. Ballast 

Blwr. Blower 

Brkr. Breaker 











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"C" ABBREVIATION TABLE
"C" ABBREVIATION TABLE







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ABBREVIATION DEFINITION 










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C Celsius (Degrees) 

C(3) I Computer Controlled Coil Ignition 

C(4) Computer Controlled Catalytic Converter 

CANP Canister Purge solenoid 

CARB California Air Resources Board 

CAT Catalytic Converter 

CB Circuit Breaker 

CBD Closed Bowl Distributor 

CBVV Carburetor Bowl Vent Valve 

cc Cubic Centimeter 

CCC Computer Command Control 

CCD Computer Controlled Dwell 

CCM Central Control Module 

CCO Converter Clutch Override 

CCOT Cycling Clutch Orifice Tube 

CCW Counterclockwise 

CDI Capacitor Discharge Ignition 

CEC Computerized Engine Control 

CFI Central Fuel Injection 

CID Cubic Inch Displacement 

CID Cylinder Identification sensor 

CIS Continuous Injection System 

CIS-E Continuous Injection System-Electronic 

CKT Circuit 

CLR Clear 

CNG Compressed Natural Gas 

FR ............................................ Fill Pipe Restrictor
HO2S .......................................... Heated Oxygen Sensor
MIL .................................... Malfunction Indicator Light
PCV ................................. Positive Crankcase Ventilation
SFI ............................ Sequential Multiport Fuel Injection
SPK ................................................. Spark Controls
SPK-CC ..................................... SPK Computer Controlled
TWC .................................. Three-Way Catalytic Converter









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Heated Oxygen Sensor (Front)
(Federal) Underside of vehicle, forward
of catalytic converter.
Heated Oxygen Sensor (Front)
(Left Bank) (Calif.) In left exhaust manifold.
Heated Oxygen Sensor (Front)
(Right Bank) (Calif.) In right exhaust manifold.
Heated Oxygen Sensor (Rear)
(Federal) Underside of vehicle, behind
catalytic converter.
Heated Oxygen Sensor (Rear) (Left Bank)
(Calif.) In left exhaust pipe, below
engine.
Heated Oxygen Sensor (Rear) (Right Bank)
(Calif.) In right exhaust pipe, below
engine.
Input Shaft Speed Sensor On side of transmission.
Intake Air Temperature Sensor Mounted on outside of
evaporator case.
Manifold Differential Pressure Sensor On top left rear of engine.
Output Shaft Speed Sensor On rear of transmission.

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

converter with the exception of the catalyst. See Fig. 5. The TWC
converter uses rhodium, with or without platinum, as its catalyst.
Rhodium helps reduce NOx emissions, as well as HC and CO.
Visually check for presence of catalytic converter(s). Also
check for presence of any required air supply system for the oxidizing
section of the converter. Check for external damage such as severe
dents, removed or damaged heat shields, etc. Check for pellets or
pieces of converter in the tailpipe.
Three-Way Catalyst + Oxidation Catalyst (TWC + OC)
This system contains a TWC converter and an OC converter in a
common housing, separated by a small air space. See Fig. 6. The 2
catalysts are referred to as catalyst beds. Exhaust gases pass through
the TWC first. The TWC bed performs the same function as it would as a
separate device, reducing all 3 emissions. As exhaust gases leave the
bed, they pass through the air space and into the second (OC)
converter catalyst bed.
Visually check for presence of catalytic converter(s). Check
for external damage such as severe dents, removed or damaged heat
shields, etc. Check for pellets or pieces of converter in the
tailpipe.
Fig. 6: Typical Three-Way + Oxidation Catalytic Converter
Courtesy of General Motors Corp.
FILL PIPE RESTRICTOR (FR)
A fuel tank fill pipe restrictor is used to prohibit the
introduction of leaded fuel into the fuel tank. Unleaded gasoline pump
dispensers have a smaller diameter nozzle to fit fuel tank of vehicle
requiring the use of unleaded fuel (vehicles equipped with catalytic
converter).
Visually inspect fill pipe restrictor(s) for tampering, i.e.,\
restrictor is oversize or the flapper is non-functional. If vehicle is
equipped with an auxiliary fuel tank, ensure auxiliary fuel tank is
also equipped with a fill pipe restrictor.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM

Fig. 14: Typical Pulsed Secondary Air Injection System
Courtesy of General Motors Corp.
OXYGEN SENSOR (O2)
The O2 sensor is mounted in the exhaust system where it
monitors oxygen content of exhaust gases. Some vehicles may use 2 O2
sensors. The O2 sensor produces a voltage signal which is proportional
to exhaust gas oxygen concentration (0-3%) compared to outside oxygen
(20-21%). This voltage signal is low (about .1 volt) when a lean
mixture is present and high (1.0 volt) when a rich mixture is present.\
As ECM compensates for a lean or rich condition, this voltage
signal constantly fluctuates between high and low, crossing a
reference voltage supplied by the ECM on the O2 signal line. This is
referred to as cross counts. A problem in the O2 sensor circuit should
set a related trouble code.
COMPUTERIZED ENGINE CONTROLS (CEC)
The CEC system monitors and controls a variety of
engine/vehicle functions. The CEC system is primarily an emission
control system designed to maintain a 14.7:1 air/fuel ratio under most
operating conditions. When the ideal air/fuel ratio is maintained, the
catalytic converter can control oxides of nitrogen (NOx), hydrocarbon
(HC) and carbon monoxide (CO) emissions.
The CEC system consists of the following sub-systems:
Electronic Control Module (ECM), input devices (sensors and switches)\
and output signals.

* EXHAUST SYSTEM UNIFORM INSPECTION GUIDELINES *
1998 Mitsubishi Montero
GENERAL INFORMATION
Exhaust Systems Motorist Assurance Program
Standards For Automotive Repair
All Makes and Models
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
CONTENTS
Motorist Assurance Program (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
OVERVIEW OF SERVICE REQUIREMENTS AND SUGGESTIONS
Exhaust
CATALYTIC CONVERTERS
EXHAUST AND TAIL PIPES
EXHAUST CONNECTIONS
HANGERS
HEAT RISERS (MECHANICAL EFE DEVICES)
HEAT SHIELDS
MANIFOLDS (CAST AND TUBE TYPE)
MECHANICAL EFE DEVICES
MUFFLERS AND RESONATORS
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
The Motorist Assurance Program is the consumer outreach
effort of the Automotive Maintenance and Repair Association, Inc.
(AMRA). Participation in the Motorist Assurance Program is drawn from
retailers, suppliers, independent repair facilities, vehicle
manufacturers and industry associations.
Our organization's mission is to strengthen the relationship
between the consumer and the auto repair industry. We produce
materials that give motorists the information and encouragement to
take greater responsibility for their vehicles-through proper,
manufacturer-recommended, maintenance. We encourage participating
service and repair shops (including franchisees and dealers) to adopt
(1) a Pledge of Assurance to their Customers and (2) the Motorist
Assurance Program Standards of Service. All participating service
providers have agreed to subscribe to this Pledge and to adhere to the
promulgated Standards of Service demonstrating to their customers that
they are serious about customer satisfaction.
These Standards of Service require that an inspection of the
vehicle's (problem) system be made and the results communicated to the\
customer according to industry standards. Given that the industry did
not have such standards, the Motorist Assurance Program successfully
promulgated industry inspection communication standards in 1994-95 for
the following systems: Exhaust, Brakes, ABS, Steering and Suspension,
Engine Maintenance and Performance, HVAC, and Electrical Systems.
Further, revisions to all of these inspection communication standards
are continually re-published. In addition to these, standards for
Drive Train and Transmissions have recently been promulgated.
Participating shops utilize these Uniform Inspection & Communication

1 - Part is close to the end of its useful life (just above
discard specifications, or weak; failure likely to occur
soon, etc.)
2 - To address a customer need, convenience, or request (to
stiffen ride, enhance performance, eliminate noise,
etc.)
3 - To comply with maintenance recommended by the vehicle's
Original Equipment Manufacturer (OEM)
4 - Technician's recommendation based on substantial and
informed experience
NOTE: Suggested services are always optional. When presenting
suggested repairs to the customer, you must present
the facts, allowing the customer to draw their own
conclusions and make an informed decision about how to
proceed.
EXHAUST
SERVICE PROCEDURES REQUIRED AND SUGGESTED FOR PROPER
VEHICLE OPERATION
WARNING: Federal EPA rules prohibit altering an exhaust system in
any way that defeats the emission reduction components of a
vehicle. Be sure to review and adhere to EPA policy on
removing and replacing catalytic converters. Where state or
local laws are stricter, they take precedence over these
guidelines.
NOTE: Some exhaust systems are of a welded design. It is not
required that the entire system be replaced. Determine the
need to replace individual components based on conditions of
component.
CATALYTIC CONVERTERS
CAUTION: Before working on an exhaust system, review EPA
regulations on removing and replacing catalytic converters.
NOTE: Any time a converter has failed, further diagnosis is
required to determine the reason(s) for converter failure.
CATALYTIC CONVERTER INSPECTION









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Condition Code Procedure
Air injection tube
broken ................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
burnt .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
leaking ................ A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube

loose .................. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
restricted ............. A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads damaged ........ A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Air injection tube
threads stripped
(threads missing) ...... A ... Require repair or replacement
of injection tube or
replacement of catalytic
converter.
Body cracked ............ B .. Require repair or replacement.
Converter empty ......... A .. Require repair or replacement.
Converter fill plug
missing ................ C .. Require repair or replacement.
Converter missing ....... C ............ Require replacement.
Exhaust gases leaking ... A .. Require repair or replacement.
Flanges leaking ......... A ... Require repair or replacement
of flanges.
Inlet pipes cracked ..... B .. Require repair or replacement.
Internal rattle (except
pellet-type) ........... 2 .......... (1) Further inspection
required.
Mounting brackets that
are part of converter
broken ................. A .. Require repair or replacement.
Obvious overheating ..... .. ......... ( 2) Require testing of
converter.
Outlet pipes cracked .... B .. Require repair or replacement.
Pieces of catalyst
material found
downstream ............. 1 ............ Suggest replacement.
Plugged ................. A ........ ( 3) Require replacement.
Testing has determined
that existing converter
has been lead-poisoned,
contaminated, or failed
testing ................ A .. Require repair or replacement.
( 1) - If the converter is breaking up, suggest converter
replacement. If an object has fallen into the converter,
remove the object.
( 2) - Overheating is caused by something other than the
converter. Further diagnosis is required to determine
the cause of the overheating.
( 3) - Determine cause and correct to ensure that new converter
will not become plugged.









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EXHAUST AND TAIL PIPES
NOTE: For pipes with resonators, also see MUFFLERS AND RESONATORS.
EXHAUST AND TAIL PIPE INSPECTION

2.0L
(VIN F) ........................................ 8.5:1
(VIN Y) ........................................ 9.6:1
2.4L (VIN G) ..................................... 9.5:1
3.0L
(VIN H) ........................................ 8.9:1
(VIN J) ....................................... 10.0:1
(VIN K) ........................................ 8.0:1
(VIN P) ........................................ 9.0:1
3.5L (VIN M & P) ................................. 9.0:1
Compression Pressure
1.5L (VIN A) ..................... 192 psi (13.4 kg/cm
)
1.8L (VIN C) ..................... 199 psi (13.9 kg/cm)
2.0L (VIN F) ..................... 178 psi (12.5 kg/cm)
2.0L (VIN Y) ............ 170-225 psi (11.7-15.5 kg/cm)
2.4L (VIN G) ..................... 192 psi (13.4 kg/cm)
3.0L
(VIN H & P) .................... 171 psi (12.0 kg/cm
)
(VIN J) ........................ 185 psi (13.0 kg/cm)
(VIN K) ........................ 156 psi (10.9 kg/cm)
3.5L (VIN M & P) ................. 171 psi (12.0 kg/cm)
Maximum Variation
Between Cylinders ( 2) ............... 14 psi (1.0 kg/cm
)
( 1) - See A - ENGINE/VIN ID article for VIN information.
( 2) - On Eclipse 2.0L non-turbo engine, maximum variation
between cylinders is 25%.









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Exhaust System Backpressure
The exhaust system can be tested with a vacuum or pressure
gauge. If using a pressure gauge, remove HO2S or air injection check
valve (if equipped). Connect a 0-5 psi pressure gauge and run engine
at 2500 RPM. If exhaust system backpressure is greater than 2 psi,
exhaust system or catalytic converter is plugged.
If using a vacuum gauge, connect vacuum gauge hose to intake
manifold vacuum port. Start engine. Observe vacuum gauge. Open
throttle part way and hold steady. If vacuum gauge indication slowly
drops after stabilizing, inspect exhaust system for restriction.
FUEL SYSTEM
* PLEASE READ THIS FIRST *
WARNING: ALWAYS relieve fuel pressure before disconnecting any fuel
injection-related component. DO NOT allow fuel to contact
engine or electrical components.
RELIEVING FUEL PRESSURE
1) On Diamante, disconnect fuel pump harness connector at
fuel tank from underneath vehicle. On Montero and Montero Sport,
remove cargo compartment carpet, remove access plate and disconnect
fuel pump harness connector. On all other models, remove rear seat
cushion, remove access plate (if required) and disconnect fuel pump
harness connector.
2) On all models, start engine. Let engine run until it
stops. Turn ignition off. Disconnect negative battery cable. Connect
fuel pump harness connector. Install rear seat and/or carpet as
necessary.
WARNING: Before disconnecting high pressure fuel hose at fuel