1991 MITSUBISHI MONTERO ECU

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.

terminal "B" and negative lead to positive battery terminal. Reconnect
negative battery cable.
3) Start engine. Turn accessories on and adjust engine speed
until ammeter indicates 20 amps, and note voltmeter reading. If
voltmeter indicates .2 volt or less, system is okay.
4) If voltage is greater than .2 volt, wiring is defective
between alternator terminal "B", fusible link and battery positive
terminal. Disconnect negative battery cable, and remove test
equipment.
ALTERNATOR OUTPUT TEST
NOTE: During alternator output test, a slightly discharged battery
should be used as a fully charged battery may not allow full
alternator output.
1) Turn ignition switch to OFF position. Disconnect negative
battery cable. Disconnect alternator output wire from terminal "B".
Install positive lead of 100-amp ammeter to terminal "B" and negative
lead to disconnected output lead.
CAUTION: Tighten each connection securely as heavy current flow will
exist. DO NOT use clips on ammeter.
2) Connect positive voltmeter lead (0-20 volts) to alternato\
r
terminal "B" and negative lead to ground. Install tachometer, and
reconnect negative battery cable.
3) Ensure voltmeter indicates battery voltage. If no voltage
exists, an open circuit is present in wire between alternator terminal
"B" and battery negative terminal. Check grounds and fusible link.
4) Turn headlights on, and start engine. Set headlights at
high beam and heater switch on HIGH. Quickly accelerate engine speed
to 2500 RPM and note alternator output current registered on the
ammeter. Minimum output should be within specification. Refer to the
ALTERNATOR MINIMUM OUTPUT SPECIFICATIONS table.
NOTE: Output voltage changes with electrical load and temperature.
Ensure proper electrical load is applied while checking
output. Nominal output may not be obtained if alternator or
ambient temperature is excessive. Allow to cool, and recheck
output. Alternator output is stamped on metal plate attached
to alternator case.
5) If minimum output is not obtained and alternator wiring is
okay, repair alternator. Disconnect negative battery cable, and remove
test equipment.
REGULATED VOLTAGE TEST
NOTE: Ensure battery is fully charged and proper drive belt
tension exists.
1) Turn ignition switch to OFF position. Disconnect negative
battery cable. Install a digital voltmeter between alternator terminal
"S" and ground. See Fig. 10. Connect positive voltmeter lead to
terminal "S" of alternator. Connect negative voltmeter lead to ground.
2) Disconnect alternator output wire from terminal "B".
Install a 100-amp ammeter in series to terminal "B" and disconnected
output lead. Install positive lead of ammeter to terminal "B" and
negative lead to disconnected output wire. Install a tachometer, and
reconnect negative battery cable.
3) Turn ignition switch to ON position and ensure voltmeter
indicates battery voltage. If no voltage exists, an open circuit

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:

Wear indicator device
(mechanical) contacts
rotor .................. .. ......... (6) Further inspection
required.
Worn close to minimum
specifications ......... 1 ........ ( 7) Suggest replacement.
Worn to, or below minimum
specifications ......... B ............ Require replacement.
( 1) - Identify and repair cause of contamination prior to
replacing friction material.
( 2) - When reconditioning or replacing drums or rotors,
replacement of friction material may be suggested
depending on the severity of the grooves or ridges.
( 3) - Some vehicles use pads that are tapered by design. Refer
to specific vehicle application. If not normal, require
replacement of pads and correction of cause.
( 4) - Uneven pad thickness is normal on some vehicles. Refer to
specific vehicle applications.
( 5) - The pad wear indicator light may come on due to other
electrical problems.
( 6) - Explain to the customer that the purpose of the wear
indicator is to alert him or her to check for friction
wear. Wear indicators may be bent or broken. Therefore,
the friction material must be measured. The need for
friction material replacement is determined based upon
the conditions stated in this section. Periodic inspection
is suggested.
( 7) - When the part appears to be close to the end of its useful
life, replacement may be suggested.









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G SENSORS
See ACCELEROMETERS .
HOSES
HOSE 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.
Blistered ............... B ............ Require replacement.
Fitting threads damaged . A .. Require repair or replacement.
Fitting threads stripped
(threads missing) ...... A ............ Require replacement.
Incorrectly secured ..... B ................. Require repair.
Inner fabric
(webbing) cut .......... B ............ Require replacement.
Leaking ................. A ............ Require replacement.
Missing ................. C ............ Require replacement.
Outer covering is cracked
to the extent that
inner fabric of hose

(3) - Inspect for conditions related to wheel cylinder.
( 4) - Leaking is defined as a drop or more. Dampness is normal.









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WIRING HARNESSES
NOTE: Copied from Electrical UIGs.
WIRING HARNESS INSPECTION









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Condition Code Procedure
Application incorrect ... B .. Require repair or replacement.
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.
Connector broken ........ A .. Require repair or replacement.
Connector (Weatherpack
type) leaking .......... A .. Require repair or replacement.
Connector melted ........ A ........... ( 1) Require repair or
replacement.
Connector missing ....... C ............ Require replacement.
Insulation damaged,
conductors exposed ..... A .. Require repair or replacement.
Insulation damaged,
conductors not exposed . 1 ............ Suggest replacement.
Open .................... A .. Require repair or replacement.
Protective shield
(conduit) melted ....... 2 ........... ( 1) Suggest repair or
replacement.
Protective shield
(conduit) missing ...... 2 .. Suggest repair or replacement.
Resistance (voltage drop)
out of specification ... A .. Require repair or replacement.
Routed incorrectly ...... B ................. Require repair.
Secured incorrectly ..... B ................. Require repair.
Shorted ................. A .. Require repair or replacement.
Terminal broken ......... A .. Require repair or replacement.
Terminal burned, affecting
performance ............ A ........... ( 1) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Voltage drop out of
specification .......... A .. Require repair or replacement.
( 1) - Determine cause and correct prior to repair or
replacement of part.









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Removal
1) Raise and support vehicle. Remove front wheel(s). Separat\
e
rubber flex hose from hydraulic line at brake hose mount, located on
strut housing. Secure end of hydraulic line to prevent spillage of
brake fluid.
2) Remove hose clip from brake hose mount. Disconnect brake
hose from caliper. Remove upper and lower caliper-to-steering knuckle
bolts. Lift caliper body upward. Remove caliper.
Installation
To install, reverse removal procedure. Tighten bolts to
specification. See the TORQUE SPECIFICATIONS table. Bleed brake
system. See BLEEDING BRAKE SYSTEM .
FRONT BRAKE ROTOR
Removal (Montero, Pickup 4WD & Ram-50 4WD)
Raise and support vehicle. Remove and support brake calipers.
Place hub in free-wheeling position. Remove drive hub cover using an
oil filter wrench and protective cloth. Remove snap ring, shim and
free-wheeling hub from drive axle. See Fig. 7. Remove lock washer.
Remove lock nut using Lock Nut Wrench (MB990954). Remove front hub
assembly.
Fig. 7: Exploded View of Front Brake Assembly (4WD)
Courtesy of Mitsubishi Motor Sales of America.
Installation
1) Install front hub assembly. Install and tighten lock nut
to 94-145 ft. lbs. (127-197 N.m), and then loosen and retighten to 18
ft. lbs. (24 N.m). Loosen lock nut 30-40 degrees. Reverse removal
procedure for remaining components. After installation is complete,
check drive axle end play. Adjust end play if not .002" (.05 mm) or
less. Rotate drive axle forward and rearward until maximum end play is
obtained.
2) If adjusting axle shaft end play, use proper shim to
obtain desired end play. Shim is located behind snap ring on end of
drive axle. Install shim, and recheck axle end play.
Removal (Pickup 2WD & Ram-50 2WD)
Raise and support vehicle. Remove front caliper. Remove hub
(dust) cap, cotter pin and nut. Remove washer and outer wheel bearing.\
Remove front hub assembly. Remove bolts attaching rotor to front hub,
and separate assemblies.

POWER BRAKE UNIT CHECK VALVE
NOTE: To test check valve before removal, stop engine, and apply
service brake to ensure air flows only toward intake
manifold.
Removal & Installation
Loosen hose clamps, and remove check valve. Before
installation, coat both ends of check valve with sealant, and install
valve with arrow (identification mark) pointing toward intake
manifold. Install check valve clamp, and secure hose clamps.
POWER BRAKE UNIT
Removal
Remove brake master cylinder. Disconnect vacuum hose from
power brake unit. Disconnect clevis pin attaching brake pedal to power
brake unit push rod. From inside vehicle, remove 4 nuts attaching
power brake unit to firewall. Remove power brake unit.
Installation
To install, reverse removal procedure. Install master
cylinder. Bleed brake system if necessary.
REAR AXLE BEARINGS & OIL SEAL
Removal (Montero)
1) With drum removed, disconnect brake line from wheel
cylinder. Disconnect bearing case from axle housing end. Remove brake
backing plate, bearing case and axle shaft as an assembly. If axle
shaft binds, use slide hammer with puller to remove.
2) Remove "O" ring and shims for preloading wheel bearing (if\
equipped). Retain shims for reassembly. To remove oil seal, use slide
hammer and hook.
3) To remove wheel bearing, straighten lock washer tabs. See
Fig. 9 . Remove lock nut using spanner wrench. Remove lock washer.
Install lock nut 3 turns on axle shaft. Install Puller (MB990787-01)
to remove axle shaft from bearing case. Rotate nuts with equal force
to remove axle shaft. Remove bearing outer race using a hammer and
drift.
Fig. 9: Removing Rear Axle Bearing (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Installation
1) Apply Multipurpose Grease (SAE J310) to oil seal. Install\

cylinder. Disconnect parking brake cable end, and remove cable
attaching bolts. Remove brake backing plate, bearing case and axle
shaft as an assembly. If axle shaft binds, use slide hammer with
puller to remove.
2) Remove shims, "O" ring and snap ring. Retain shims for
reassembly. Secure axle shaft assembly in a vise, and remove one
retainer bolt from backing plate. Push bearing case completely to side
of dust cover. Place adhesive tape around edge of bearing case at
retainer bolt hole to prevent damage.
3) Secure axle shaft, and grind retainer ring until retainer
ring wall thickness is .04-.06" (1.0-1.5 mm) on axle shaft side and
retainer ring wall thickness is .08" (2.0 mm) on bearing side. See
Fig. 11.
CAUTION: DO NOT damage bearing case or axle shaft when grinding or
chiseling retainer ring.
4) Change angle of grind, and remove remaining .08" (2.0 mm)\
of retainer ring wall on bearing side. See Fig. 11. Using a chisel,
cut retainer ring, and remove. DO NOT damage axle shaft.
Fig. 11: Grinding Bearing Retainer Ring (Pickup & Ram-50)
Courtesy of Mitsubishi Motor Sales of America.
5) Install Puller (MB990787-01) to remove bearing case from
axle shaft. Rotate nuts with equal force to remove wheel bearing.