check engine light MITSUBISHI MONTERO 1991 User Guide

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EN G IN E O VER HAU L P R O CED URES - G EN ER AL IN FO RM ATIO N

1991 M it s u bis h i M onte ro
Engine Overhaul Procedures - General Information
ALL PISTON ENGINES
* PLEASE READ THIS FIRST *
Examples used in this article are general in nature and do
not necessarily relate to a specific engine or system. Illustrations
and procedures have been chosen to guide mechanic through engine
overhaul process. Descriptions of processes of cleaning, inspection,
assembly and machine shop practice are included.
Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and specifications
for the vehicle being repaired.
ENGINE IDENTIFICATION
The engine may be identified from its Vehicle Identification
Number (VIN) stamped on a metal tab. Metal tab may be located in
different locations depending on manufacturer. Engine identification
number or serial number is located on cylinder block. Location varies
with manufacturer.
INSPECTION PROCEDURES
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
GENERAL
Engine components must be inspected to meet manufacturer's
specifications and tolerances during overhaul. Proper dimensions and
tolerances must be met to obtain proper performance and maximum engine
life.
Micrometers, depth gauges and dial indicator are used for
checking tolerances during engine overhaul. Magnaflux, Magnaglo, dye-
check, ultrasonic and x-ray inspection procedures are used for parts
inspection.
MAGNETIC PARTICLE INSPECTION
Magnaflux & Magnaglo
Magnaflux is an inspection technique used to locate material
flaws and stress cracks. The part in question is subjected to a strong
magnetic field. The entire part, or a localized area, can be
magnetized. The part is coated with either a wet or dry material that
contains fine magnetic particles.
Cracks which are outlined by the particles cause an
interruption in the magnetic field. The dry powder method of Magnaflux
can be used in normal light. A crack will appear as an obvious bright
line.
Fluorescent liquid is used in conjunction with a blacklight
in a second Magnaflux system called Magnaglo. This type of inspection
demands a darkened room. The crack will appear as a glowing line in
this process. Both systems require complete demagnetizing upon

completion of the inspection. Magnetic particle inspection applies to
ferrous materials only.
PENETRANT INSPECTION
Zyglo
The Zyglo process coats the material with a fluorescent dye
penetrant. The part is often warmed to expand cracks that will be
penetrated by the dye. When the coated part is subjected to inspection
with a blacklight, a crack will glow brightly. Developing solution
is often used to enhance results. Parts made of any material, such as
aluminum cylinder heads or plastics, may be tested using this process.
Dye Check
Penetrating dye is sprayed on the previously cleaned
component. Dye is left on component for 5-45 minutes, depending upon
material density. Component is then wiped clean and sprayed with a
developing solution. Surface cracks will show up as a bright line.
ULTRASONIC INSPECTION
If an expensive part is suspected of internal cracking,
Ultrasonic testing is used. Sound waves are used for component
inspection.
X-RAY INSPECTION
This form of inspection is used on highly stressed
components. X-ray inspection maybe used to detect internal and
external flaws in any material.
PRESSURE TESTING
Cylinder heads can be tested for cracks using a pressure
tester. Pressure testing is performed by plugging all but one of the
holes in the head and injecting air or water into the open passage.
Leaks are indicated by the appearance of wet or damp areas when using
water. When air is used, it is necessary to spray the head surface
with a soap solution. Bubbles will indicate a leak. Cylinder head may
also be submerged in water heated to specified temperature to check
for cracks created during heat expansion.
CLEANING PROCEDURES
* PLEASE READ THIS FIRST *
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
GENERAL
All components of an engine do not have the same cleaning
requirements. Physical methods include bead blasting and manual
removal. Chemical methods include solvent blast, solvent tank, hot
tank, cold tank and steam cleaning of components.
BEAD BLASTING
Manual removal of deposits may be required prior to bead
blasting, followed by some other cleaning method. Carbon, paint and

NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
REMOVAL
Remove intake and exhaust manifolds and valve cover. Cylinder
head and camshaft carrier bolts (if equipped), should be removed only
when the engine is cold. On many aluminum cylinder heads, removal
while hot will cause cylinder head warpage. Mark rocker arm or
overhead cam components for location.
Remove rocker arm components or overhead cam components.
Components must be installed in original location. Individual design
rocker arms may utilize shafts, ball-type pedestal mounts or no rocker
arms. For all design types, wire components together and identify
according to the corresponding valve. Remove cylinder head bolts.
Note length and location. Some applications require cylinder head
bolts be removed in proper sequence to prevent cylinder head damage.
See Fig. 1 . Remove cylinder head.
Fig. 1: Typical Cylinder Head Tightening or Loosening Sequence
This Graphic For General Information Only
INSTALLATION
Ensure all surfaces and head bolts are clean. Check that head
bolt holes of cylinder block are clean and dry to prevent block damage
when bolts are tightened. Clean threads with tap to ensure accurate
bolt torque.
Install head gasket on cylinder block. Some manufacturer's
may recommend sealant be applied to head gasket prior to installation.
Note that all holes are aligned. Some gasket applications may be
marked so certain area faces upward. Install cylinder head using care
not to damage head gasket. Ensure cylinder head is fully seated on
cylinder block.
Some applications require head bolts be coated with sealant
prior to installation. This is done if head bolts are exposed to water
passages. Some applications require head bolts be coated with light
coat of engine oil.

during manufacture, some new type valves cannot be reground.
Resurface valve on proper angle specification using valve
grinding machine. Follow manufacturer's instructions for valve
grinding machine. Specifications may indicate a different valve face
angle than seat angle.
Measure valve margin after grinding. Replace valve if not
within specification. Valve stem tip can be refinished using valve
grinding machine.
Valve Lapping
During valve lapping of recent designed valves, be sure to
follow manufacturers recommendations. Surface hardening and materials
used with some valves do not permit lapping. Lapping process will
remove excessive amounts of the hardened surface.
Valve lapping is done to ensure adequate sealing between
valve face and seat. Use either a hand drill or lapping stick with
suction cup attached.
Moisten and attach suction cup to valve. Lubricate valve stem
and guide. Apply a thin coat of fine valve grinding compound between
valve and seat. Rotate lapping tool between the palms or with hand
drill.
Lift valve upward off the seat and change position often.
This is done to prevent grooving of valve seat. Lap valve until a
smooth polished seat is obtained. Thoroughly clean grinding compound
from components. Valve to valve seat concentricity should be checked.
See VALVE SEAT CONCENTRICITY.
CAUTION: Valve guides must be in good condition and free of carbon
deposits prior to valve seat grinding. Some engines contain
an induction hardened valve seat. Excessive material removal
will damage valve seats.
Valve Seat Grinding
Select coarse stone of correct size and angle for seat to be
ground. Ensure stone is true and has a smooth surface. Select correct
size pilot for valve guide dimension. Install pilot in valve guide.
Lightly lubricate pilot shaft. Install stone on pilot. Move stone off
and on the seat approximately 2 times per second during grinding
operation.
Select a fine stone to finish grinding operation. Grinding
stones with 30 and 60 degree angles are used to center and narrow the
valve seat as required. See Fig. 10.
Fig. 10: Adjusting Valve Seat Width - Typical
This Graphic For General Information Only
Valve Seat Replacement
Replacement of valve seat inserts is done by cutting out

over connecting rod bolts. Install piston and connecting rod assembly.
Ensure piston notch, arrow or "FRONT" mark is toward front of engine.
See Fig. 17 .
Fig. 17: Installing Piston & Connecting Rod Assembly - Typical
This Graphic For General Information Only
Carefully tap piston into cylinder until rod bearing is
seated on crankshaft journal. Remove protectors. Install rod cap and
bearing. Lightly tighten connecting rod bolts. Repeat procedure for
remaining cylinders. Check bearing clearance. See
MAIN & CONNECTING ROD BEARING CLEARANCE in this article.
Once clearance is checked, lubricate journals and bearings.
Install bearing caps. Ensure marks are aligned on connecting rod and
cap. Tighten rod nuts or bolts to specification. Ensure rod moves
freely on crankshaft. Check connecting rod side clearance. See
CONNECTING ROD SIDE CLEARANCE in this article.
CONNECTING ROD SIDE CLEARANCE
Position connecting rod toward one side of crankshaft as far
as possible. Using feeler gauge, measure clearance between side of
connecting rod and crankshaft. See Fig. 18. Clearance must be within
specifications.

With lever set at OUTSIDE position, outside air is allowed to enter
and/or pass through heater. With lever set at INSIDE position, air is
recirculated inside passenger compartment.
BLOWER SWITCH
The blower can be operated at different fan speeds to
regulate amount of air forced through vehicle. Fan speed will increase
as switch is turned or moved right.
AIR CONTROL INDICATION SYSTEM
This system consists of indication lights built into
instrument cluster and 4 switches connected to various control levers.
An indication light glows when heater blower is on. Lights also
indicate choice of outlets and whether air source is inside or outside
vehicle. In addition, temperature of air directed from outlets is
indicated for each air outlet by light colors of green (cool air) and
orange (warm air).
ADJUSTMENTS
HEATER (TEMPERATURE) CONTROL VALVE
Place control lever to indicated position. See TEMPERATURE
CONTROL CABLE ADJUSTMENT table. See Fig. 3. Connect cable to heater
control valve and/or air damper lever according to table. Secure cable
sleeve using clips. With engine running, check for coolant leaks and
check operation of heater control valve. If heater control valve does
not operate properly, adjust by moving cable sleeve forward or
backward at retaining clip.
TEMPERATURE CONTROL CABLE ADJUSTMENT TABLE









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Application Control Lever Water Valve
Position Lever Position
Montero .................... Far Left ............... Toward cable
Pickup & Ram-50 ............ Far Left ........ (2) Away from cable
(2) - Disconnect link between air damper lever and water valve
lever. Close water valve. Close air damper. Reconnect link.
Attach cable to clip.









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Fig. 3: Adjusting Temperature Control Cable (Typical)
Courtesy of Mitsubishi Motor Sales of America.
INSIDE/OUTSIDE AIR SELECTION CABLE

screws. Remove dash panel.
4) Remove blower duct, center duct and defroster ducts. See
Fig. 2. Disconnect heater wiring harness from heater unit. Remove
heater center support brackets. Remove heater unit. Remove heater core
cover plate and joint hose. Remove heater core from heater unit.
Installation
1) To install, reverse removal procedure. Insert heater hoses
fully into pipes, and clamp securely to prevent leaks.
2) When filling radiator with coolant, first open heater
control valve fully and run engine to circulate coolant and discharge
air from inside heater and engine cooling system. Stop engine, and add
coolant.
3) Adjust all control cables. When installing heater hose
grommets, apply sealer. After installing heater control assembly,
ensure each lever operates smoothly.
HEATER CONTROL PANEL
Removal (Montero)
1) Remove heater control knob and heater fan switch knob.
Remove center console. Remove defroster nozzle at temperature control
cable side.
2) Remove lap heater duct and glove box stopper, and push
glove box forward and down. Disconnect inside/outside control cable
from blower assembly.
3) Disconnect control cables from heater unit. Remove heater
control panel mounting screws, and pull out panel slightly. Disconnect
heater fan switch harness connectors. Remove heater control panel.
Remove heater fan switch from heater control panel.
Installation
1) Place air outlet change-over lever at closed position.
With heater side air outlet change-over damper lever in position,
connect inner cable to lever, and secure cable casing using clips.
2) Place heater control lever at OFF position. With heater
control lever in position, connect inner cable to lever, and secure
cable casing using clips.
3) Place inside/outside air change-over lever at INSIDE
position. With heater side inside/outside air change-over damper lever
in position, connect inner cable to lever, and secure cable casing
using clips.
4) Set control lever to each position to check for correct
operation. If lever does not operate correctly, adjust by moving outer
wire at clipped point. Ensure each control lever moves smoothly. If
any noise or stiff movement exists, apply multipurpose grease to all
moving parts.
NOTE: When mounting heater control panel to instrument panel,
tighten upper bolts to instrument panel so they also secure
center panel.
Removal & Installation (Pickup & Ram-50)
Remove cluster panel. Remove all control cables at heater.
Remove heater control panel. To install, reverse removal procedure.
Adjust cables as necessary.
WIRING DIAGRAMS

OIL PRESSURE GAUGE
Circuit Test
Disconnect oil pressure gauge wiring connector from sending
unit inside the engine compartment. Connect a 12-volt test light
between harness connector terminal and ground. Turn ignition on, but
DO NOT start engine. If test light comes on and gauge needle moves, go
to GAUGE RESISTANCE TEST. If test light does not come on and gauge
needle does not move, repair wiring to sending unit.
Gauge Resistance Test
Remove instrument cluster from instrument panel. See
INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Check continuity
between oil pressure gauge terminals. See Fig. 4 or Fig. 5. See
OIL PRESSURE GAUGE RESISTANCE SPECIFICATIONS table. If resistance is
not within specification, replace oil pressure gauge.
OIL PRESSURE GAUGE RESISTANCE SPECIFICATIONS TABLE









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Application Ohms
Montero ...................................... 50
Pickup & Ram-50 ........................... 37-47









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Fig. 4: Oil Pressure Gauge Test Terminal ID (Pickup & Ram-50)
Courtesy of Chrysler Motors

Calibration Test
Adjust tire pressure to standard value. Using a calibrated,
reliable speedometer tester, compare reading of vehicle speedometer to
speedometer tester. See SPEEDOMETER ALLOWABLE VARIATION table. Replace
speedometer if necessary.
SPEEDOMETER ALLOWABLE VARIATION TABLE









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MPH (km/h) Allowable Variation MPH (km/h)
20 (32) .......................... 19-22 (31-35)
40 (64) .......................... 38-44 (61-71)
60 (97) ......................... 57-66 (92-106)
80 (129) ....................... 76-88 (122-142)
100 (161) ..................... 94-110 (151-177)









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TACHOMETER
NOTE: DO NOT reverse polarity when installing tachometer, as diode
and transistor may be damaged.
Calibration Test
Connect a calibrated, reliable tach-dwell meter to vehicle
ignition system. Operate engine at various speeds (RPM). See
TACHOMETER ALLOWABLE VARIATION table. If comparison between tach-dwell
meter and vehicle tachometer readings do not fall in the standard
range of permissible variation, replace vehicle tachometer.
TACHOMETER ALLOWABLE VARIATION TABLE









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Engine Speed (RPM) Allowable Variation (RPM)
1000 .................................. 900-1100
3000 ................................. 2850-3150
5000 ................................. 4750-5250
6000 ................................. 5700-6300









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TEMPERATURE GAUGE
CAUTION: DO NOT connect sender wire directly to ground during test.
Circuit Test
Disconnect temperature sender wire from sending unit. Connect
a 12-volt, 3.4-watt test bulb between connector terminal and ground.
Turn ignition switch to ON position. If test bulb flashes and
temperature gauge needle moves, go to SENSOR RESISTANCE TEST. If test
light does not flash and gauge needle does not move, repair wiring to
sending unit.
Sensor Resistance Test
Remove thermosensor (sending unit) from engine block. Place
sending unit in hot water of 158
F (70C) temperature. Check sensor
resistance with an ohmmeter. Thermosensor resistance should be 90-117
ohms at 158
F (70C). If thermosensor resistance in okay, go to GAUGE
RESISTANCE TEST. Replace thermosensor if resistance is not as
specified.
Gauge Resistance Test
Remove instrument cluster from instrument panel. See
INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Measure resistance
between temperature gauge terminals at rear of cluster or combination

1985-87 ........ (2) 2.4L 4-Cyl. .......... ( 4) 60,000
1988 ............... 3.0L V6 .............. ( 3) 60,000
1989-93 .... ( 2) 2.0L 4-Cyl. (DOHC) ....... ( 4) 60,000
2.0L 4-Cyl. (SOHC) ........ ( 4) 60,000
1994-96 .... ( 2) 2.4L 4-Cyl. (DOHC) ....... ( 4) 60,000
2.4L 4-Cyl. (SOHC) ........ ( 4) 60,000
Mirage
1985-96 ........ ( 2) 1.5L 4-Cyl. .............. 60,000
1985-88 ..... ( 2) 1.6L 4-Cyl. Turbo ........... 60,000
1989, 1991 ..... ( 2) 1.6L 4-Cyl. .............. 60,000
1993-96 ........... 1.8L 4-Cyl ................ 60,000
Precis
1987-93 ........ ( 2) 1.5L 4-Cyl. .............. 60,000
Sigma
1989-90 ............ 3.0L V6 .............. ( 3) 60,000
Tredia
1983-88 .......... 1.8L 4-Cyl. ............ ( 4) 60,000
2.0L 4-Cyl. ............ ( 4) 60,000
3000GT
1991-96 .......... ( 2) 3.0L V6 ................ 60,000
Light Trucks
Montero
1985-96 ............ 3.0L V6 .............. ( 3) 60,000
1994-96 ............ 3.5L V6 .............. ( 3) 60,000
Pickup
1983-89 ........... 2.0L 4-Cyl. ........... ( 3) 60,000
1983-86 ... ( 2) 2.3L 4-Cyl. Turbo Diesel .. ( 4) 60,000
1990-96 ........... 2.4L 4-Cyl. ........... ( 4) 60,000
3.0L V6 .............. ( 3) 60,000
Van
1987-90 ........... 2.4L 4-Cyl. ........... ( 4) 60,000
( 1) - Other interference engine applications may exist which
are not indicated here.
( 2) - Interference engine. Check for possible damage to
piston(s) or valve(s) if there has been a timing belt
failure.
( 3) - Although the vehicle manufacturer does not recommend a
specific scheduled maintenance interval, aftermarket
belt manufacturers suggest the belt be replaced at
60,000 mile intervals.
( 4) - Vehicle manufacturer recommends replacing all belts at
the same time.









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