MITSUBISHI MONTERO 1991 Service Manual
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AN TI- L O CK B RAK E S A FE TY P R EC AU TIO NS
1991 M it s u bis h i M onte ro
GENERAL INFORMATION
Anti-Lock Brake Safety Precautions
* PLEASE READ THIS FIRST *
This article is intended for general information purposes
only. This information may not apply to all makes and models. If
vehicle is equipped with Anti-Lock Brake System (ABS), refer to
appropriate ANTI-LOCK BRAKE SYSTEM article in the BRAKES section for
description, operation, depressurizing, testing, system bleeding,
trouble shooting and servicing of specific system.
WARNING: Failure to depressurize ABS could lead to physical injury.
ANTI-LOCK BRAKE SAFETY PRECAUTIONS
WARNING: Failure to depressurize ABS could lead to physical injury.
* NEVER open a bleeder valve or loosen a hydraulic line
while ABS is pressurized.
* NEVER disconnect or reconnect any electrical connectors
while ignition is on. Damage to ABS control unit may result.
* DO NOT attempt to bleed hyudarulic system without first
referring to the appropriate ANTI-LOCK BRAKE SYSTEM article
in the BRAKES section.
* Only use specially designed brake hoses/lines on ABS equipped
vehicles.
* DO NOT tap on speed sensor components (sensor, sensor rings).
Sensor rings must be pressed into hubs, NOT hammered into
hubs. Striking these components can cause demagnetization or
a loss of polarization, affecting the accuracy of the speed
signal returning to the ABS control unit.
* DO NOT mix tire sizes. Increasing the width, as long as tires
remain close to the original diameter, is acceptable. Rolling
diameter must be identical for all 4 tires. Some
manufacturers recommend tires of the same brand, style and
type. Failure to follow this precaution may cause inaccurate
wheel speed readings.
* DO NOT contaminate speed sensor components with grease. Only
use recommended coating, when system calls for an
anti-corrosion coating.
* When speed sensor components have been removed, ALWAYS check
sensor-to-ring air gaps when applicable. These specifications
can be found in each appropriate article.
* ONLY use rocommended brake fluids. DO NOT use silicone brake
fluids in an ABS equipped vehicle.
* When instlling transmittion devices (CB's, telephones, etc.)
on ABS equipped vehicles, DO NOT locate the antenna near the
ABS control unit (or any control unit).
* Disconnect all on-board computers, when using electric
welding equipment.
* DO NOT expose the ABS control unit to prolonged periods of
high heat (185
F/85 C for 2 hours is generally considered a
maximum limit).
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F - B ASIC T E STIN G
1991 M it s u bis h i M onte ro
1991 ENGINE PERFORMANCE
Basic Diagnostic Procedures
Chrysler; Colt, Colt 200, Colt Vista, Ram-50, Stealth,
Summit
Mitsubishi; Eclipse, Galant, Mirage, Montero, Pickup, 3000GT
INTRODUCTION
The following diagnostic steps will help prevent overlooking
a simple problem. This is also where to begin diagnosis for a no start
condition. First step in diagnosing any driveability problem is
verifying customer's complaint with a test drive under conditions
problem reportedly occurred.
Before entering self-diagnostics, perform a careful and
complete visual inspection. Most engine control problems result from
mechanical breakdowns, poor electrical connections or
damaged/misrouted vacuum hoses. Before condemning computerized system,
perform each test listed in article.
NOTE: Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM)\
with a minimum 10-megohm input impedance, unless stated
otherwise in test procedure.
PRELIMINARY INSPECTION & ADJUSTMENTS
VISUAL INSPECTION
Visually inspect all electrical wiring, looking for chafed,
stretched, cut or pinched wiring. Ensure electrical connectors fit
tightly and are not corroded. Ensure distributor cap and rotor are
free of cracks, carbon trails or contamination. Ensure vacuum hoses
are properly routed and not pinched or cut. See M - VACUUM DIAGRAMS
article in the ENGINE PERFORMANCE Section to verify routing and
connections (if necessary). Inspect air induction system for possible
vacuum leaks.
MECHANICAL INSPECTION
Compression
Check engine mechanical condition with a compression gauge,
vacuum gauge, or an engine analyzer. See engine analyzer manual for
specific instructions.
WARNING: DO NOT use ignition switch during compression tests. Use a
remote starter to crank engine. Fuel injectors on many models
are triggered by ignition switch during cranking mode, which
can create a fire hazard or contaminate engine's oiling
system.
COMPRESSION SPECIFICATIONS TABLE (1)
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Application Specification
psi (kg/cm)
1.5L (VIN X) .............................. 137 (9.6)
1.6L (VIN Y) ............................. 171 (12.0)
1.8L (VIN T) .............................. 131 (9.2)
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2.0L (VIN R) DOHC ......................... 137 (9.6)
2.0L (VIN U) DOHC Turbo ................... 114 (8.0)
2.0L (VIN V) SOHC ......................... 119 (8.4)
2.4L (VIN W) SOHC ......................... 119 (8.4)
3.0L (VIN S) SOHC ......................... 119 (8.4)
3.0L (VIN B) DOHC ......................... 139 (9.8)
3.0L (VIN C) DOHC Turbo ................... 115 (8.1)
(1) - Maximum variation between cylinders 14 psi
(1.0 kg/cm
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Exhaust System Backpressure
Exhaust system can be checked with a vacuum or pressure
gauge. Remove O2 sensor or air injection check valve (if equipped).
Connect a 1-10 psi pressure gauge and run engine at 2500 RPM. If
exhaust system backpressure is greater than 1 3/4-2 psi, exhaust
system or catalytic converter is plugged. If a vacuum gauge is used,
connect vacuum gauge hose to intake manifold vacuum port and start
engine. Observe vacuum gauge. Open throttle part way and hold steady.
If vacuum gauge reading slowly drops after stabilizing, exhaust system
should be checked for a restriction.
FUEL PRESSURE
Basic diagnosis of fuel system should begin with determining
fuel system pressure.
FUEL INJECTED ENGINES
WARNING: ALWAYS relieve fuel pressure before disconnecting any fuel
injection-related component. DO NOT allow fuel to contact
engine or electrical components.
Fuel Pressure
1) On all models except Colt and Mirage, disconnect fuel pump
harness connector at fuel tank. On Colt and Mirage, remove rear seat
cushion to disconnect fuel pump harness connector.
2) On all models, start engine. Let engine run until it
stops. Turn ignition off. Disconnect negative battery terminal.
Connect fuel pump harness connector.
WARNING: Before disconnecting high pressure fuel hose at fuel delivery
pipe, cover fuel hose connection with a rag. Some residual
fuel pressure may still be in system.
3) On Galant 2.0L (DOHC), remove brace for access to high
pressure fuel delivery pipe. On all engines, disconnect high pressure
fuel hose at fuel delivery pipe.
4) Connect fuel pressure gauge with adapter between fuel
delivery pipe and high pressure hose. See Fig. 1. Connect negative
battery terminal. Connect battery voltage to fuel pump test terminal.
See FUEL PUMP TEST TERMINAL LOCATION table. Ensure no fuel leaks are
present. Disconnect battery voltage to fuel pump test terminal.
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Fig. 1: Fuel Pressure Testing Connection ID (Typical Fuel Inj. Eng.)
Courtesy of Mitsubishi Motor Sales of America.
5) Start engine and let idle. Measure fuel pressure with
vacuum hose connected to fuel pressure regulator. Record fuel pressure
reading. Disconnect and plug vacuum hose from fuel pressure regulator.
Record fuel pressure reading. See REGULATED FUEL PRESSURE table.
6) Check for fuel pressure in fuel return hose by gently
pinching hose while increasing engine speed. If fuel volume is low,
fuel pressure in return hose will not be felt. Increase engine speed
to 2500-3000 RPM, 2-3 times. Return engine to idle. Fuel pressure
should not drop when engine is returned to idle.
7) Turn engine off. Ensure fuel pressure reading does not
decrease within 2 minutes. If a decrease is noted, monitor speed of
decrease.
8) If fuel pressure is lower than specification, fuel
pressure drops at idle after increasing engine speed to 2500-3000 RPM,
or no fuel pressure in fuel return hose can be felt, check for clogged
fuel filter, faulty fuel pressure regulator, or fuel pump.
9) If fuel pressure is higher than specification, check for a
faulty fuel pressure regulator or plugged fuel return line. If fuel
pressure does not change when vacuum hose to regulator is connected or
disconnected, check for a leaking or clogged vacuum hose to fuel
pressure regulator or faulty fuel pressure regulator.
10) If fuel pressure decreases suddenly after engine is
stopped, check valve within fuel pump is not seated. Replace fuel
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pump. If fuel pressure drops slowly, fuel injector is leaking or fuel
pressure regulator valve seat is leaking. Check for faulty fuel
injector or fuel pressure regulator. Repair as required.
11) When fuel pressure test is complete, repeat fuel pressure
release procedure in steps 1) and 2) before disconnecting fuel
pressure gauge. Install new "O" ring at end of high pressure hose.
Check for fuel leaks.
FUEL PUMP TEST TERMINAL LOCATION TABLE
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Application Wire Color Location
Colt, Colt 200 ......... BLK/WHT .............. Center Of Firewall
Colt Vista ............. BLK/WHT ........ Right Center Of Firewall
Eclipse ................ BLK/WHT .......... Rear Of Battery Compt.
Galant ................. YEL/GRN ........... Left Rear Eng. Compt.
Mirage 1.5L ............ BLK/WHT .............. Center Of Firewall
Mirage 1.6L ............ BLK/BLU .............. Center Of Firewall
Montero .................. WHT .......... Right Center Of Firewall
Pickup ................. BLK/BLU ....... Right Side Of Eng. Compt.
Precis ................... YEL ............. Left Rear Eng. Compt.
Summit ................. BLK/WHT .............. Center Of Firewall
Ram-50 ................. BLK/BLU ....... Right Side Of Eng. Compt.
Stealth, 3000GT ........ BLK/BLU .......... Rear Of Battery Compt.
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REGULATED FUEL PRESSURE TABLE \
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At Idle At Idle
w/Vacuum w/o Vacuum
Application psi (kg/cm
) psi (kg/cm)
Non-Turbo .................. 38 (2.7) ....... 47-50 (3.3-3.5)
Turbo
Except Eclipse A/T ....... 27 (1.9) ....... 36-38 (2.5-2.7)
Eclipse A/T .............. 33 (2.3) ....... 36-38 (2.9-3.2)
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Control Relay
Multipurpose relay switches power to vehicle sensors and
actuators including airflow sensor, crank angle sensor, idle speed
control, injectors and fuel pump. When ignition switch is turned to ON
position, ECU energizes coils controlling injectors, airflow sensor
and idle speed control. When ignition switch is turned to START
position, ECU energizes coils (through inhibitor switch on A/T models)\
to supply power to fuel pump. Relay failure will cause a no-start
condition. For testing procedure, see SYSTEM & COMPONENT TESTING
article.
IGNITION CHECKS
SPARK
Check for spark at coil wire (if applicable) and at each
spark plug wire using a high output spark tester. Check spark plug
wire resistance on suspect wires. For wire resistance specification,
see C - SPECIFICATIONS article in the ENGINE PERFORMANCE Section.
CRANK ANGLE SENSOR
For crank angle sensor testing procedure on all models except
Ram-50, Stealth, Eclipse, Laser, Pickup and 3000GT, see TEST NS-5:
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TESTING CRANK ANGLE SENSOR CIRCUIT - G - TESTS W/CODES article in the
ENGINE PERFORMANCE section.
On Eclipse and Laser, see NS-4A: REPAIRING CRANK ANGLE SENSOR
in G - TESTS W/CODES - 1.8L article.
On Ram-50, Stealth, Pickup and 3000GT testing information not
available at time of publication.
DISTRIBUTORLESS IGNITION SYSTEM (DIS)
Ignition Coil Resistance (4-Cyl Vehicles Except Eclipse 2.0L)
1) Using a Digital Volt/Ohmmeter (DVOM), measure primary coi\
l
resistance between ignition coil connector terminals No. 2 and No. 3
(coils for cylinders No. 1 and No. 4) and terminals No. 1 and No. 3
(coils for cylinders No. 2 and No. 3). See Fig. 2.
Fig. 2: Testing Ignition Coil Primary Resistance (4-Cylinder)
Courtesy of Mitsubishi Motor Sales of America.
2) Measure secondary coil resistance between coil towers for
cylinders No. 1 and No. 4 and between coil towers for cylinders No. 2
and No. 3. See Fig. 3. Primary and secondary coil resistance should be
within specification. See DIS IGNITION COIL RESISTANCE table.
Fig. 3: Testing Ignition Coil Secondary Resistance (4-Cylinder)
Courtesy of Mitsubishi Motor Sales of America.
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Ignition Coil Resistance (Eclipse 2.0L)
1) Using a DVOM, measure primary coil resistance between
ignition coil connector terminals No. 2 and No. 4 (coils for cylinders
No. 1 and No. 4) and between terminals No. 4 and No. 1 (coils for
cylinders No. 2 and No. 3). See Fig. 2.
2) Measure secondary coil resistance between coil towers for
cylinders No. 1 and No. 4 and between coil towers for cylinders No. 2
and No. 3. See Fig. 3. Primary and secondary coil resistance should be
within specification. See DIS IGNITION COIL RESISTANCE table.
DIS IGNITION COIL RESISTANCE TABLE Ohms @ 68
F (20C) \
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Application Primary Secondary
All Models ........... .77-.95 .......... 10.3-13.9
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Power Transistor (Eclipse)
1) Disconnect power transistor connector. Using an analog
ohmmeter, connect positive ohmmeter lead to terminal No. 7 and
negative lead to terminal No. 3. See Fig. 4. Ensure there is no
continuity.
Fig. 4: Power Transistor Connector ID (Eclipse)
Courtesy of Mitsubishi Motor Sales of America.
2) Using a 1.5-volt dry cell battery, connect positive end of
1.5-volt battery to power transistor terminal No. 6 and negative end
to terminal No. 3. Ohmmeter should now read continuity between power
transistor terminals No. 7 and No. 3.
3) Connect positive end of 1.5-volt battery to power
transistor terminal No. 2 and negative end to terminal No. 3. Connect
positive ohmmeter lead to terminal No. 1 and negative lead to terminal
No. 3. Ohmmeter should read continuity. Replace power transistor if it
does not test as described.
Power Transistor (Colt Vista, Galant, Montero, Pickup &
Ram-50)
1) Disconnect power transistor connectors. Using a DVOM,
connect positive ohmmeter lead to terminal No. 2 and negative lead to
terminal No. 3. See Fig. 5. Ensure there is no continuity.
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2) Using a 1.5-volt dry cell battery, connect positive end of
1.5-volt battery to power transistor terminal No. 1 and negative end
to terminal No. 2. DVOM should now read continuity at power transistor
terminals No. 2 and No. 3. Replace power transistor if it does not
test as described. See Fig. 6.
Fig. 5: Power Trans Conn ID (Colt Vista, Galant, Montero, P/U & Ram
50)
Courtesy of Mitsubishi Motor Sales of America.
Fig. 6: Testing Power Trans (Colt Vista, Galant, Montero, Pickup &
Ram-50)
Courtesy of Mitsubishi Motor Sales of America.
Power Transistor (Colt, Colt 200, Mirage & Summit)
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1) Disconnect power transistor connectors. Using a DVOM,
connect positive ohmmeter lead to terminal No. 2 and negative lead to
terminal No. 7. See Fig. 7. Ensure there is no continuity.
2) Using a 1.5-volt dry cell battery, connect positive end of
1.5-volt battery to power transistor terminal No. 8 and negative end
to terminal No. 7. DVOM should now read continuity at power transistor
terminals No. 2 and No. 7. Replace power transistor if it does not
test as described.
Fig. 7: Power Transistor Connector ID (Colt, Summit & Mirage)
Courtesy of Mitsubishi Motor Sales of America.
Power Transistor (Stealth & 3000GT)
When testing power transistor, refer to POWER TRANSISTOR
TESTING (STEALTH & 3000GT) table.
Fig. 8: Power Transistor Connector ID (Stealth & 3000GT)
Courtesy of Mitsubishi Motor Sales of America.
POWER TRANSISTOR TESTING TABLE (STEALTH & 3000GT) (1)
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(2) Analog Ohmmeter (2) With 1.5 V Battery
Cylinders Connected Between Connected Between
Tested Terminals (No 1.5 V Battery) Terminals\
1 & 4 ......... 3 & 7 No Continuity ....... 6 & 7 Continuity
2 & 5 ......... 2 & 7 No Continuity ....... 5 & 7 Continuity
3 & 6 ......... 1 & 7 No Continuity ....... 4 & 7 Continuity
(1) - All tests performed with power transistor disconnected. Replace
power transistor if it does not test as described.
(2) - See Fig. 8 for terminal identification.
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MAGNETIC & OPTICAL IGNITION
Ignition Coil Resistance
1) Using a DVOM, measure primary coil resistance between
positive and negative terminals of coil. See Fig. 9. For ignition coil
terminal identification See Fig. 11 - 13.
2) Measure secondary coil resistance between coil positive
terminal and ignition coil tower. See Fig. 10.
3) Primary and secondary coil resistance should be within
specification. See IGNITION COIL RESISTANCE table.
Fig. 9: Testing Ignition Coil Primary Resistance (6-Cylinder)
Courtesy of Mitsubishi Motor Sales of America.