light MITSUBISHI MONTERO 1991 Service Manual

the iron core here.
This pintle hump at Point "E" should occur near the end of
the downward slope, and not afterwards. If it does occur after the
slope has ended and the voltage has stabilized, it is because the
pintle is slightly sticking because of a faulty injector
If you see more than one hump it is because of a distorted
pintle or seat. This faulty condition is known as "pintle float".
It is important to realize that it takes a good digital
storage oscilloscope or analog lab scope to see this pintle hump
clearly. Unfortunately, it cannot always be seen.
Fig. 2: Identifying Voltage Controlled Type Injector Pattern
INTERPRETING A CURRENT CONTROLLED PATTERN
NOTE: Current controlled drivers are also known as "Peak and Hold"

drivers. They typically require injector circuits
with a total leg resistance with less than 12 ohm.
NOTE: This example is based on a constant power/switched ground
circuit.
* See Fig. 3 for pattern that the following text describes.
Point "A" is where system voltage is supplied to the
injector. A good hot run voltage is usually 13.5 or more volts. This
point, commonly known as open circuit voltage, is critical because the
injector will not get sufficient current saturation if there is a
voltage shortfall. To obtain a good look at this precise point, you
will need to shift your Lab Scope to five volts per division.
You will find that some systems have slight voltage
fluctuations here. This could occur if the injector feed wire is also
used to power up other cycling components, like the ignition coil(s).
Slight voltage fluctuations are normal and are no reason for concern.
Major voltage fluctuations are a different story, however. Major
voltage shifts on the injector feed line will create injector
performance problems. Look for excessive resistance problems in the
feed circuit if you see big shifts and repair as necessary.
Point "B" is where the driver completes the circuit to
ground. This point of the waveform should be a clean square point
straight down with no rounded edges. It is during this period that
current saturation of the injector windings is taking place and the
driver is heavily stressed. Weak drivers will distort this vertical
line.
Point "C" represents the voltage drop across the injector
windings. Point "C" should come very close to the ground reference
point, but not quite touch. This is because the driver has a small
amount of inherent resistance. Any significant offset from ground is
an indication of a resistance problem on the ground circuit that needs
repaired. You might miss this fault if you do not use the negative
battery post for your Lab Scope hook-up, so it is HIGHLY recommended
that you use the battery as your hook-up.
Right after Point "C", something interesting happens. Notice
the trace starts a normal upward bend. This slight inductive rise is
created by the effects of counter voltage and is normal. This is
because the low circuit resistance allowed a fast build-up of the
magnetic field, which in turn created the counter voltage.
Point "D" is the start of the current limiting, also known as
the "Hold" time. Before this point, the driver had allowed the current
to free-flow ("Peak") just to get the injector pintle open. By the
time point "D" occurs, the injector pintle has already opened and the
computer has just significantly throttled the current back. It does
this by only allowing a few volts through to maintain the minimum
current required to keep the pintle open.
The height of the voltage spike seen at the top of Point "D"
represents the electrical condition of the injector windings. The
height of this voltage spike (inductive kick) is proportional to the
number of windings and the current flow through them. The more current
flow and greater number of windings, the more potential for a greater
inductive kick. The opposite is also true. The less current flow or
fewer windings means less inductive kick. Typically you should see a
minimum 35 volts.
If you see approximately 35 volts, it is because a zener
diode is used with the driver to clamp the voltage. Make sure the
beginning top of the spike is squared off, indicating the zener dumped
the remainder of the spike. If it is not squared, that indicates the
spike is not strong enough to make the zener fully dump, meaning there
is a problem with a weak injector winding.
If a zener diode is not used in the computer, the spike from

a good injector will be 60 or more volts.
At Point "E", notice that the trace is now just a few volts
below system voltage and the injector is in the current limiting, or
the "Hold" part of the pattern. This line will either remain flat and
stable as shown here, or will cycle up and down rapidly. Both are
normal methods to limit current flow. Any distortion may indicate
shorted windings.
Point "F" is the actual turn-off point of the driver (and
injector). To measure the millisecond on-time of the injector, measure
between points "C" and "F". Note that we used cursors to do it for us;
they are measuring a 2.56 mS on-time.
The top of Point "F" (second inductive kick) is created by
the collapsing magnetic field caused by the final turn-off of the
driver. This spike should be like the spike on top of point "D".
Point "G" shows a slight hump. This is actually the
mechanical injector pintle closing. Recall that moving an iron core
through a magnetic field will create a voltage surge. The pintle is
the iron core here.
This pintle hump at Point "E" should occur near the end of
the downward slope, and not afterwards. If it does occur after the
slope has ended and the voltage has stabilized, it is because the
pintle is slightly sticking. Some older Nissan TBI systems suffered
from this.
If you see more than one hump it is because of a distorted
pintle or seat. This faulty condition is known as "pintle float".
It is important to realize that it takes a good digital
storage oscilloscope or analog lab scope to see this pintle hump
clearly. Unfortunately, it cannot always be seen.
Fig. 3: Identifying Current Controlled Type Injector Pattern

Fig. 2: Identifying Front Wiper Relay Terminals (Montero)
Courtesy of Mitsubishi Motor Sales of America.
Intermittent Operation Check (Montero)
1) Connect battery voltage to terminal No. 1 and ground
terminal No. 6. See Fig. 2. Connect a jumper wire with test light
between battery positive and terminal No. 2.
2) Connect one end of a jumper wire to terminal No. 3 and
touch the other end to negative terminal on battery. Test light should
illuminate briefly and then go out after terminal No. 3 is touched to
battery ground.
FRONT WIPER SWITCH
NOTE: Front wiper switch is located on steering column.
See STEERING COLUMN SWITCHES article in the
ACCESSORIES/SAFETY EQUIP Section.
REAR WIPER MOTOR
Operation Check (Montero)
Disconnect wiring connector from wiper motor. Connect battery
voltage to one terminal and ground to other terminal to ensure
automatic operation. See REAR WIPER MOTOR OPERATION CHECK table for
terminal numbers and model application. See Fig. 3.
REAR WIPER MOTOR OPERATION CHECK TABLE









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Model Ground Pin No. Apply Voltage To Pin Nos.
Montero ................. 3 .................................... 1









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Montero
Remove wiper switch from instrument panel and disconnect
wiring connector. Place wiper switch in OFF position. Continuity
should exist between terminals No. 2 and 5. See Fig. 5. Place wiper
switch in ON position. Continuity should exist between terminals No. 2
and 7. Place wiper switch in INT position. Continuity should exist
between terminals No. 2 and 5, and 3 and 8. Depress washer switch.
Continuity should exist between terminals No. 6 and 7.
Fig. 5: Identifying Rear Wiper Switch Terminals
Courtesy of Mitsubishi Motor Sales of America.
REMOVAL & INSTALLATION
FRONT WIPER MOTOR
Removal & Installation
Remove wiper motor attaching bolts. Pull motor out just
slightly. Disconnect wiper linkage from motor assembly and remove
motor. To install, reverse removal procedure.
FRONT WIPER SWITCH
NOTE: Front wiper switch is integral with combination switch on
steering column. See appropriate STEERING COLUMN SWITCHES

Fig. 2: Identifying Option Symbols
COLOR ABBREVIATIONS IDENTIFICATION
COLOR ABBREVIATIONS








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Color Normal Optional
Black .................. BLK ................... BK
Blue ................... BLU ................... BU
Brown .................. BRN ................... BN
Clear .................. CLR ................... CR
Dark Blue ............ DK BLU ............... DK BU
Dark Green ........... DK GRN ............... DK GN
Green .................. GRN ................... GN
Gray ................... GRY ................... GY
Light Blue ........... LT BLU ............... LT BU
Light Green .......... LT GRN ............... LT GN
Orange ................. ORG ................... OG
Pink ................... PNK ................... PK
Purple ................. PPL ................... PL
Red .................... RED ................... RD
Tan .................... TAN ................... TN
Voilet ................. VIO ................... VI

Fig. 8: Diode (Light Emitting)
Fig. 9: Defogger Grid
Fig. 10: Fuse
Fig. 11: Fusible Link
Fig. 12: Ground
Fig. 13: Glow Plug Resistor (In-Line) or Mirror Heater
Fig. 14: Injector (Diesel) or Photocell (Gasoline)

WIR IN G D IA G RAM S

1991 M it s u bis h i M onte ro
1991 Wiring Diagrams
Mitsubishi
Montero
IDENTIFICATION
COMPONENT LOCATION MENU
COMPONENT LOCATIONS TABLE








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Component Figure No. (Location)
A/C RELAYS .......................... 4 (C 12), 4 (A-B 15)
A/C SYSTEM ................................. 4 (A-C 12-15)
ALTERNATOR ................................... 1 (B-C 1-2)
ALTERNATOR RELAY ............................... 1 (C 1-2)
AUTO FREE-WHEELING HUB CONTROL UNIT ............. 3 (D 11)
BACK DOOR LOCK SW ............................... 7 (B 27)
BACK-UP LT SW (M/T) ............................. 7 (A 26)
BATTERY .......................................... 1 (A 1)
BLOWER SWITCH ................................. 4 (A-B 12)
BUZZER .......................................... 5 (E 17)
CARGO LIGHT ..................................... 6 (A 23)
CIG LIGHTER ..................................... 3 (E 11)
CLOCK ........................................... 3 (E 11)
COLUMN SW ..................................... 5 (A-E 19)
CRUISE CONTROL SYSTEM ...................... 4 (D-E 13-15)
DEFOGGER ...................................... 7 (C-D 27)
DIAG CONNECTION .................................. 2 (E 7)
DIMMER CONTROL SWITCH ............................ 3 (E 8)
DIR FLASHER ..................................... 5 (C 16)
DIR SWITCH ...................................... 5 (C 19)
DOME LT ............................... 6 (A 23), 7 (A 24)
DOOR LOCK SYSTEM ........................... 6 (D-E 21-23)
DOOR SWITCHES ......................... 5 (D 17), 6 (C 23)
FRONT WIPER SYSTEM ........................... 5 (A 16-17)
FUEL GAUGE UNIT ................................. 6 (C 22)
FUEL PUMP ........................................ 2 (C 4)
FUSE BLOCK .................................... 3 (C 9-10)
HAZARD FLASHER .................................. 5 (C 16)
HAZARD SW ....................................... 5 (B 16)
HEAD LIGHT WASHER RELAY ....................... 5 (C-D 17)
HEATER RELAY .................................... 4 (A 12)
HORN SWITCH ..................................... 5 (E 19)
IGNITION COIL .................................... 2 (E 4)
IGNITION SW ..................................... 3 (A 11)
ILLUMINATION LIGHTS ............................ 3 (D-E 8)
INHIBITOR SW ..................................... 3 (A 9)
INSTRUMENT CLUSTER ............................ 6 (A-D 20)
KEY REMINDER SW ................................. 5 (E-17)
LIGHT CONTROL RELAY ............................. 5 (E 19)
LIGHT SWITCH .................................... 5 (D 19)
MAIN FUSE LINKS ................................ 1 (A 1-2)
METER UNIT ...................................... 6 (E 20)
MPI CONTROL RELAY ................................ 2 (B 4)
MPI CONTROL UNIT ............................... 2 (A 4-7)
NOISE FILTER ..................................... 2 (E 6)
OVERDRIVE CONTROL RELAY .......................... 3 (A 8)

OVERDRIVE SWITCH ................................. 3 (A 8)
PARKING BRAKE SWITCH ............................ 6 (A 21)
POWER TRANSISTOR ................................. 2 (D 4)
POWER WINDOWS .............................. 7 (B-E 24-26)
RADIO (PARTIAL) ............................... 3 (D-E 10)
REAR BLOWER SWITCH .............................. 4 (D 12)
REAR WIPER .................................... 5 (D-E 16)
SEAT BELT WARNING TIMER ......................... 5 (D 18)
STARTER .......................................... 1 (C 3)
STOP LIGHT SWITCH ..................... 4 (E 13), 5 (C 16)
SUB FUSE LINKS ................................... 1 (A 3)
SUNROOF ...................................... 7 (A 24-25)
WIPER SWITCH .................................. 5 (A-B 19)









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WIRING DIAGRAMS

Fig. 1: Engine Compt, Headlights, (Grid 1-3)