1991 MITSUBISHI MONTERO coolant temperature

A/T Thermoswitch On thermostat housing.
Brakelight Switch On bracket, above brake pedal.
Clutch Switch On bracket, above brake pedal.
Coolant Temperature Switch On front of intake manifold.

These 3 orifices are opened and closed by electric solenoids. The
solenoids are, in turn, controlled by the Electronic Control Module
(ECM). When a solenoid is energized, the armature with attached shaft
and swivel pintle is lifted, opening the orifice. See Fig. 11.
The ECM uses inputs from the Coolant Temperature Sensor
(CTS), Throttle Position Sensor (TPS) and Mass Airflow (MAF) senso\
rs
to control the EGR orifices to make 7 different combinations for
precise EGR flow control. At idle, the EGR valve allows a very small
amount of exhaust gas to enter the intake manifold. This EGR valve
normally operates above idle speed during warm engine operation.
Verify EGR valve is present and not modified or purposely
damaged. Ensure thermal vacuum switches, pressure transducers, speed
switches, etc., (if applicable) are not by-passed or modified. Ensure
vacuum hose(s) to EGR valve is not plugged. Ensure electrical
connector to EGR valve is not disconnected.
Fig. 11: Typical Digital EGR Valve
Courtesy of General Motors Corp.
Integrated Electronic EGR Valve
This type functions similar to a ported EGR valve with a

Fig. 2: Testing Electric Cooling Fan Relay (3000GT)
Courtesy of Mitsubishi Motor Sales of America.
ELECTRIC COOLING FAN - SYSTEM TESTING
MIRAGE 1.5L
1) With A/C on LOW position, ignition on and engine coolant
temperature greater than 185F (85C), thermosensor completes path to
ground, closing radiator fan motor relay contacts and providing
current to radiator fan motor. See Fig. 1.
2) With A/C on HIGH position and ignition on, power supply
from automatic compressor control unit causes condenser fan motor
relay and condenser fan motor control relay to turn on, causing
condenser fan and radiator cooling fan to operate.

MIRAGE 1.6L
1) With A/C on LOW position, ignition on and engine coolant
temperature greater than 185F (85C), thermosensor completes path to
ground, closing radiator fan motor relay contacts and providing
current to radiator fan motor. See Fig. 2.
2) With A/C on HIGH position and ignition on, power supply
from auto compressor control unit causes condenser fan motor relay to
turn on, causing condenser fan and radiator cooling fan to operate at
a low speed by usage of a resistor.
3) If pressure switch is activated by excessive pressure or
if thermosensor is on when engine coolant temperature exceeds 185
F
(85C), condenser fan motor control relay is activated, causing
condenser fan and radiator cooling fan to operate at a high speed.
ECLIPSE & 3000GT
With ignition on and engine coolant temperature greater than
185F (85C), thermosensor completes path to ground, closing radiator
fan motor relay contacts and providing current to radiator fan. See
Figs. 7 -11.
WIRING DIAGRAMS
For addition wiring diagrams, see appropriate chassis wiring
diagrams in WIRING DIAGRAMS.

Engine pre-oiling can be done using pressure oiler (if
available). Connect pressure oiler to cylinder block oil passage
such as oil pressure sending unit. Operate pressure oiler long enough
to ensure correct amount of oil has filled crankcase. Check oil level
while pre-oiling.
If pressure oiler is not available, disconnect ignition
system. Remove oil pressure sending unit and replace with oil pressure
test gauge. Using starter motor, rotate engine starter until gauge
shows normal oil pressure for several seconds. DO NOT crank engine
for more than 30 seconds to avoid starter motor damage.
Ensure oil pressure has reached the most distant point from
the oil pump. Reinstall oil pressure sending unit. Reconnect ignition
system.
INITIAL START-UP
Start the engine and operate engine at low speed while
checking for coolant, fuel and oil leaks. Stop engine. Recheck coolant
and oil level. Adjust if necessary.
CAMSHAFT
Break-in procedure is required when a new or reground
camshaft has been installed. Operate and maintain engine speed between
1500-2500 RPM for approximately 30 minutes. Procedure may vary due to
manufacturers recommendations.
PISTON RINGS
Piston rings require a break-in procedure to ensure seating
of rings to cylinder walls. Serious damage may occur to rings if
correct procedures are not followed.
Extremely high piston ring temperatures are produced obtained
during break-in process. If rings are exposed to excessively high RPM
or high cylinder pressures, ring damage can occur. Follow piston ring
manufacturer's recommended break-in procedure.
FINAL ADJUSTMENTS
Check or adjust ignition timing and dwell (if applicable).
Adjust valves (if necessary). Adjust carburetion or injection idle
speed and mixture. Retighten cylinder heads (if required). If
cylinder head or block is aluminum, retighten bolts when engine is
cold. Follow the engine manufacturer's recommended break-in procedure
and maintenance schedule for new engines.
NOTE: Some manufacturer's require that head bolts be retightened
after specified amount of operation. This must be done to
prevent head gasket failure.

CLUTCH PEDAL POSITION SWITCHES
COLD START INJECTORS
CONNECTORS
COOLANT
COOLANT RECOVERY TANKS
COOLING FAN MOTOR MODULES
COOLING FAN MOTOR RELAYS AND MODULES
COOLING FAN MOTOR RESISTORS
COOLING FAN MOTOR SENSORS AND SWITCHES
COOLING FAN MOTOR SWITCHES
COOLING FAN MOTORS
CRANKSHAFT POSITION SENSORS
DECEL VALVES
DEFLECTORS
DIP STICKS AND TUBES
DIP STICK TUBES
DISTRIBUTOR ADVANCES AND RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR BOOTS AND SHIELDS
DISTRIBUTOR CAPS
DISTRIBUTOR RETARDERS (MECHANICAL AND VACUUM)
DISTRIBUTOR ROTORS
DISTRIBUTOR SHIELDS
DISTRIBUTORS
EARLY FUEL EVAPORATION VALVES (HEAT RISER ASSEMBLIES)
EGR COOLERS
EGR EXHAUST MANIFOLD PASSAGES
EGR INTAKE AND EXHAUST MANIFOLD PASSAGES
EGR PLATES AND COOLERS
ELECTRONIC SPARK CONTROL MODULES
ELECTRONIC TRANSMISSION CONTROL DEVICES
ELECTRONIC TRANSMISSION FEEDBACK DEVICES
ENGINE COOLANT TEMPERATURE SENSORS
ENGINE COOLING SYSTEMS
ENGINE COVERS (OIL PAN, VALVE COVER, TIMING COVER)
ENGINE OIL
ENGINE OIL CANISTERS
ENGINE OIL COOLERS (EXTERNAL)
ENGINE OIL DRAIN PLUGS AND GASKETS
ENGINE OIL FILTERS AND CANISTERS
ENGINE OIL GASKETS
ENGINE OIL PRESSURE GAUGES (MECHANICAL)
EVAPORATIVE EMISSION (EVAP) CANISTER FILTERS
EVAPORATIVE EMISSION (EVAP) CANISTER PURGE DEVICES
EVAPORATIVE EMISSION (EVAP) CANISTERS
EVAPORATIVE EMISSION (EVAP) FEEDBACK DEVICES
EXHAUST GAS RECIRCULATION DEVICES
EXHAUST GAS RECIRCULATION FEEDBACK DEVICES
EXPANSION PLUGS
FAN CONTROL SENSORS
FUEL
FUEL ACCUMULATORS AND DAMPERS
FUEL AND COLD START INJECTORS
FUEL DAMPERS
FUEL DELIVERY CHECK VALVES
FUEL DISTRIBUTORS (BOSCH CIS)
FUEL FILLER NECKS AND RESTRICTORS
FUEL FILTERS
FUEL INJECTORS
FUEL LEVEL SENDERS7
FUEL PRESSURE REGULATORS
FUEL PUMPS (IN-TANK AND EXTERNAL, ELECTRICAL OR MECHANICAL)
FUEL RAILS
FUEL RESTRICTORS

fuel, metal particles, or water. Require repair or
replacement.
(3) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable;
check for accepted cleaning procedure.









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ENGINE COOLANT TEMPERATURE SENSORS
ENGINE COOLANT TEMPERATURE SENSOR INSPECTION








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Condition Code Procedure
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware
threads damaged ........ A ... Require repair or replacement
of hardware.
Attaching hardware
threads stripped
(threads missing) ...... 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.
Contaminated ............ A ........... ( 2) Require repair or
replacement.
Inoperative ............. B ........... ( 3) Require repair or
replacement. Further
inspection required.
Leaking ................. A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Resistance out of
specification .......... B .. Require repair or replacement.
Restricted, affecting
performance ............ 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.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.

Further inspection required.
Canister attaching
hardware broken ........ A ... Require repair or replacement
of hardware.
Canister attaching
hardware loose ......... A ................. Require repair.
Canister attaching
hardware missing ....... C ............ Require replacement.
Canister attaching
hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Center tube collapsed ... A ........ (2) Require replacement.
Further inspection required.
Contaminated ............ A ...... ( 3) Require replacement of
oil and filter.
Dented .................. 2 ........ ( 4) Suggest replacement.
Further inspection required.
Leaking ................. A .. Require repair or replacement.
Maintenance intervals ... 3 ... Suggest replacement to comply
with vehicle's OEM recommended
service intervals.
( 1) - Inspect pressure relief valve.
( 2) - Inspect bypass.
( 3) - Determine cause of contamination, such as engine coolant,
fuel, metal particles, or water when changing oil. Require
repair or replacement.
( 4) - Determine cause, such as broken motor mount.









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ENGINE OIL GASKETS
See ENGINE OIL DRAIN PLUGS AND GASKETS .
ENGINE OIL PRESSURE GAUGES (MECHANICAL)
ENGINE OIL PRESSURE GAUGE (MECHANICAL) INSPECTION








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Condition Code Procedure
Indicates out of range .. B .......... ( 1) Further inspection
required.
Inoperative ............. A .......... ( 2) Further inspection
required.
Leaking ................. A .. Require repair or replacement.
Reads inaccurately ...... 2 .. Suggest repair or replacement.
( 1) - Gauge may indicate problem with contaminated oil, level,
pressure, or temperature, or problem with gauge.
( 2) - Gauge may indicate problem with contaminated oil, level,
pressure, or temperature, or problem with gauge.
Inoperative includes intermittent operation, out of OEM
specification, or out of range. Further inspection
required to determine cause.









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EVAPORATIVE EMISSION (EVAP) CANISTER FILTERS
EVAPORATIVE EMISSION (EVAP) CANISTER FILTER INSPECTION








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Condition Code Procedure