1991 MITSUBISHI MONTERO set clock

other front bank camshaft sprocket.
Fig. 15: Aligning Timing Marks Final Alignment (DOHC)
Courtesy of Mitsubishi Motor Sales of America, Inc.
7) Repeat steps 4)-6) for rear cylinder bank camshafts. Alig\
n
crankshaft timing mark. Install timing belt on sprockets in sequence.
See Fig. 16 . Use spring-type paper clips to secure belt on sprockets.
Use offset box-end wrenches on camshaft sprocket bolts to keep
camshafts from turning during belt installation.
NOTE: If necessary, crankshaft sprocket may be turned one tooth
counterclockwise to aid belt installation.

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A/C C O M PR ESSO R O IL C HEC KIN G

1991 M it s u bis h i M onte ro
1991 GENERAL SERVICING
Compressor Refrigerant Oil Checking
ISOLATING COMPRESSOR
NOTE: Only compressors with stem-type service valves can be
isolated.
1) Connect service gauge set to the compressor service valves
and open compressor valves slightly (turn in clockwise). Start engine
and operate air conditioning. Slowly turn compressor suction valve
clockwise toward closed (front-seated) position.
2) When suction pressure is reduced to zero or less, turn off
engine and compressor and quickly turn suction valve stem in to full
front-seated position. Suction pressure should be slightly above zero.
Turn discharge valve into front-seated position.
3) To check oil level, slowly open compressor crankcase plug
to relieve any remaining pressure. After oil level is corrected, cap
service gauge ports on both valves. Back-seat suction service valve to
allow refrigerant to enter compressor. Open discharge valve halfway.
4) Loosen discharge service valve cap, allowing refrigerant
pressure to force air out of compressor. Back-seat service valve and
tighten cap. Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used
in the air conditioning system. This oil is highly refined and
dehydrated to a point where moisture content is less than 10 parts per
million. The oil container must be tightly closed at all times when
not in use, or moisture will be absorbed into the refrigerant oil from
the air.
SERVICING PRECAUTIONS
NOTE: Recent findings by the EPA indicate that refrigerant is
harmful to the earth's protective Ozone layer. When
discharging refrigerant, DO NOT allow refrigerant to enter
the atmosphere. If available, use refrigerant
recovery/recycle systems when discharging system. Always
follow manufacturer's instructions.
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. See ISOLATING
COMPRESSOR at the beginning of this article. Otherwise, discharge
system completely before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. DO NOT remove caps until
immediately before connections are made. This will keep entry of air

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A/C C O M PR ESSO R S ER VIC IN G

1991 M it s u bis h i M onte ro
1991 GENERAL SERVICING
Compressor Service
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
ISOLATING COMPRESSOR
NOTE: Only compressors with stem-type service valves can be
isolated.
1) Connect service gauge set to the compressor service valves
and open compressor valves slightly (turn in clockwise). Start engine
and operate air conditioning. Slowly turn compressor suction valve
clockwise toward closed (front-seated) position.
2) When suction pressure is reduced to zero or less, turn off
engine and compressor and quickly turn suction valve stem in to full
front-seated position. Suction pressure should be slightly above zero.
Turn discharge valve into front-seated position.
3) To check oil level, slowly open compressor crankcase plug
to relieve any remaining pressure. After oil level is corrected, cap
service gauge ports on both valves. Back-seat suction service valve to
allow refrigerant to enter compressor. Open discharge valve halfway.
4) Loosen discharge service valve cap, allowing refrigerant
pressure to force air out of compressor. Back-seat service valve and
tighten cap. Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used
in the air conditioning system. This oil is highly refined and
dehydrated to a point where moisture content is less than 10 parts per
million. The oil container must be tightly closed at all times when
not in use, or moisture will be absorbed into the refrigerant oil from
the air.
DISCHARGING SYSTEM PRECAUTIONS
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. Otherwise,
discharge system completely using approved refrigerant
recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. Do not remove caps until

NOTE: Fixed Speed Adjusting Screw (SAS) is preset by manufacturer
and usually does not require adjustment. Only adjust fixed
SAS if other adjustment procedures require it, or if
manufacturer's original setting has been changed.
3.0L Montero, Pickup, Ram-50, Stealth & 3000GT
1) Loosen throttle cable. Loosen fixed SAS lock nut. See
Fig. 4. Turn fixed SAS counterclockwise until throttle valve is fully
closed. Turn fixed SAS clockwise until throttle valve begins to open.
Turn fixed SAS clockwise 1 1/4 turns after throttle valve begins to
open.
2) Tighten lock nut while holding fixed SAS in position.
Adjust throttle cable. Adjust basic idle speed. See BASIC IDLE SPEED
under IDLE SPEED & MIXTURE. Adjust throttle position sensor. See
THROTTLE POSITION SENSOR (TPS).
All Other Models
To adjust fixed SAS, adjust basic idle speed. See BASIC IDLE
SPEED under IDLE SPEED & MIXTURE.
Fig. 4: Fixed Speed Adj. Screw & Feeler Gauge Pos. (3.0L)
Courtesy of Mitsubishi Motor Sales of America.
IDLE MIXTURE

NOTE: Idle mixture is computer controlled on fuel injected engines
and is nonadjustable. CO level specifications are not
available from manufacturer.
THROTTLE POSITION SENSOR (TPS)
TPS ADJUSTMENT
NOTE: Ensure basic idle speed is set to specification before
adjusting TPS. See BASIC IDLE SPEED under IDLE SPEED &
MIXTURE. Perform all adjustments with engine at normal
operating temperature, front wheels in straight-ahead
position, cooling fan and all accessories off, and
transmission in Park or Neutral.
TPS TEST APPLICATION









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Application Test
1.5L
Colt, Colt 200,
Mirage & Summit ............. TEST NO. 1
1.6L
Mirage ....................... TEST NO. 2
1.8L
Eclipse ...................... TEST NO. 3
2.0L (VIN V)
Colt Vista & Galant .......... TEST NO. 1
2.0L (VIN R & U)
Galant ....................... TEST NO. 1
Eclipse ...................... TEST NO. 3
2.4L
Pickup & Ram-50 .............. TEST NO. 1
3.0L
Montero, Pickup & Ram-50 ..... TEST NO. 4
Stealth & 3000GT ............. TEST NO. 5









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Test No. 1
1) Turn ignition on for more than 15 seconds. DO NOT start
engine. Turn ignition off. ISC plunger should be retracted fully.
2) Ensure ISC plunger is in fully retracted position.
Disconnect harness connector(s) from ISC motor. Turn ignition on. DO
NOT start engine.
3) Using digital voltmeter, backprobe terminal No. 19
(Green/White wire) and terminal No. 24 (Black or Green/Black wire) a\
t
Engine Control Unit (ECU) wiring harness connector. Note TPS output
voltage.
4) If output voltage is .48-.52 volt, go to step 6). If
output voltage is not .48-.52 volt, loosen TPS mounting screw(s) and
rotate TPS clockwise, or counterclockwise, until output voltage is
within specification. Tighten TPS mounting screws.
5) Turn ignition off. Reconnect harness connector(s) at ISC
motor. Start engine. Ensure engine idles within curb idle speed
specification.
6) Turn ignition off. Disconnect negative battery cable for
at least 15 seconds to clear diagnostic trouble code. Reconnect
negative battery cable. Operate engine at idle for about 5 minutes to
ensure engine idles smoothly.
Test No. 2
1) Turn ignition on. DO NOT start engine. Loosen throttle

Adjusting Screw (SAS) and throttle lever. See Fig. 4. Loosen TPS
mounting screws. Rotate TPS fully counterclockwise. Check for
continuity between Yellow/Red wire and Black wire terminals of TPS.
3) Rotate TPS clockwise until ohmmeter registers no
continuity. Tighten TPS mounting screws. Reconnect TPS electrical
connector.
4) Use a digital voltmeter to backprobe terminal No. 19
(Brown/Red wire) and terminal No. 24 (Brown wire) at Engine Control
Unit (ECU) wiring harness on SOHC vehicles, or terminal No. 64
(Brown/Red wire) and terminal No. 72 (Black wire) on DOHC vehicles.
Turn ignition on. DO NOT start engine. Check TPS output voltage.
5) If TPS output voltage is 0.4-1.0 volt, go to step 6). If
TPS output voltage is not 0.4-1.0 volt, check TPS and wiring harness
for damage or malfunction. Replace TPS or repair wiring harness if
necessary and go to step 6).
6) Remove feeler gauge. Turn ignition off. Disconnect
voltmeter from ECU connector. Operate engine at idle for about 5
minutes to ensure engine idles smoothly and within specification.
IDLE POSITION SWITCH
NOTE: Idle position switch is preset by manufacturer. Adjustment
is usually not necessary. If other procedures in this
article require adjustment of idle position switch or if
switch setting has been changed, adjust switch as follows.
1.6L Mirage, 2.0L Eclipse & 2.0L Galant (DOHC)
1) Loosen throttle cable. Disconnect electrical connector
from idle position switch. See Fig. 5. Loosen lock nut at base of
switch. Turn switch counterclockwise until throttle valve is fully
closed.
2) Connect ohmmeter between switch terminal and switch body
(ground). Turn idle position switch clockwise until ohmmeter registers\
continuity. At this point, throttle valve should begin to open.
3) Turn switch 15/16 of a turn beyond contact point. Tighten
lock nut at base of idle position switch, holding switch to prevent it
from turning while tightening.
4) Adjust throttle cable. Adjust basic idle speed. See BASIC
IDLE SPEED. Adjust TPS. See TPS ADJUSTMENT.
All Other Models
Idle position switch is incorporated in ISC motor and is
automatically adjusted when TPS is adjusted. See TPS ADJUSTMENT.
Fig. 5: Idle Position Switch Location (1.6L & 2.0L (VIN R &U))
Courtesy of Mitsubishi Motor Sales of America.

fluid to bring level to lower mark of dipstick if necessary. Recheck
fluid level after transmission is at normal operating temperature.
TRANSFER CASE
Drain plug is located on bottom of transfer case. Change
drain plug gasket whenever fluid is changed. On 3000GT, lubricant
level should be approximately .5" (13 mm) below fill hole on side of
transfer case. On all others models, lubricant level should be to
bottom of fill hole on side of transfer case.
HYDRAULIC CONTROL PRESSURE ADJUSTMENTS
LINE PRESSURE CHECK (EXCEPT MONTERO & PICKUP)
1) Set parking brake. Place shift lever in Neutral position.
Attach engine tachometer. Remove line pressure port plug located above
front transaxle shaft, forward of governor pressure port plug. On
Precis, line pressure port is located below bell housing, at front of
transaxle oil pan. Using appropriate adapter, attach pressure gauge.
2) Start engine, and bring to operating temperature. With
gear selector in Drive position, bring engine speed to 2500 RPM. Pull
throttle control cable (if equipped) wide open at transaxle side.
3) Line pressure should be 98-100 psi (6.9-7.0 kg/cm
) on
Mirage, or 124-127 psi (8.7-8.9 kg/cm) on all others. If line
pressure is not to specification, proceed to LINE PRESSURE ADJUSTMENT.
LINE PRESSURE ADJUSTMENT (EXCEPT MONTERO & PICKUP)
1) Drain transaxle fluid. Remove oil pan. Disconnect throttle
control cable from throttle cam. Remove oil temperature sensor (if
equipped). Disconnect solenoid connector. On some models, it may be
necessary to push solenoid wire harness connector and grommet into
transaxle case.
2) Remove oil filter screen and plate. Noting location and
length of bolts, remove valve body. DO NOT drop internal parts. Adjust
line pressure by turning regulator valve adjusting screw.
3) Turn adjusting screw counterclockwise to increase pressure
or clockwise to decrease pressure. One complete turn of adjusting
screw changes line pressure as follows.
* 3.7 psi (.26 kg/cm
) on Mirage with F3A21 Transaxle
* 5.4 psi (.39 kg/cm) on Precis
* 54 psi (3.8 kg/cm) on all others
4) After adjustment, reverse removal procedure to install.
Refill transaxle.
LINE PRESSURE (MONTERO)
1) Remove plug from line pressure take-off port located
behind transmission shift control lever. Install Hydraulic Pressure
Meter (MD998330) with Adapter (MD998206).
2) Place vehicle on dynamometer. Apply parking brake and
start engine. With brake applied, place transmission in Drive. Note
pressure at idle. Pressure should be 74-85 psi (5.2-6.0 kg/cm
).
3) Raise engine RPM to stall speed (2100-2400 RPM). Note lin\
e
pressure. Pressure should be 156-185 psi (11.0-13.0 kg/cm
).
4) Shift transmission into Reverse with brake applied. At
idle, pressure should be 112-130 psi (7.9-9.1 kg/cm
). Raise engine
RPM to stall speed (2100-2400 RPM). Note line pressure. Pressure
should be 227-285 psi (16.0-20.0 kg/cm
). If readings are not to

specification, use the following trouble shooting guide.
* Hydraulic Pressure High In All Ranges
Check throttle cable adjustment. If adjustment is okay, check
for throttle valve or regulator valve failure.
* Hydraulic Pressure Low In All Ranges
Check throttle cable adjustment. If adjustment is okay, check
for throttle valve, regulator valve, transmission oil pump or
overdrive clutch failure.
* Hydraulic Pressure Low In Drive Position
Check for fluid leaks in Drive hydraulic circuit. Check for
forward clutch or overdrive clutch failure.
* Hydraulic Pressure Low In Reverse Position
Check for fluid leaks in Reverse hydraulic circuit. Check for
transmission No. 3 brake failure, forward clutch failure or
overdrive clutch failure.
LINE PRESSURE (PICKUP)
1) Incorrect throttle pressure setting will cause incorrect
line pressure readings even though line pressure adjustment is
correct. Always inspect and correct throttle pressure adjustment
before adjusting line pressure.
2) Approximate adjustment, measured from valve body to inner
edge of adjusting nut, is 15/16". However, due to manufacturing
tolerances, adjustment can be varied to obtain correct line pressure.
3) Adjusting screw may be turned with an Allen wrench. One
complete turn of adjusting screw changes closed throttle line pressure
approximately 1 2/3 psi. Turn adjusting screw counterclockwise to
increase pressure or clockwise to decrease pressure.
THROTTLE PRESSURE (PICKUP)
1) Throttle pressures cannot be accurately tested. If a
malfunction exists, adjustment should be measured.
2) Insert Gauge Pin (C-3763) between throttle lever cam and
kickdown valve. Push in on tool to compress kickdown valve against its
spring.
3) As force is being exerted to compress spring, turn
throttle lever screw with Allen wrench until head of screw touches
throttle lever tang with gauge pin, and throttle valve bottoms. Ensure
adjustment is made with spring fully compressed and valve bottomed in
valve body.
KICKDOWN BAND
PICKUP
1) Locate kickdown band adjusting screw on left side of
transmission case. Loosen lock nut, and back off nut 5 turns. Ensure
adjusting screw turns freely in transmission case.
2) Using torque wrench, tighten adjusting screw to 72 INCH
lbs. (8 N.m). Back off adjusting screw 2 7/8 turns. Hold adjuster
screw in this position, and tighten lock nut to 30 ft. lbs. (41 N.m).
LOW-REVERSE BAND
PICKUP
1) Raise vehicle, drain transmission, and remove oil pan.
Loosen adjusting screw lock nut, and back off nut 5 turns. Ensure