
Fig. 4- l- 13 When coolant temp. rises
[Unloader system1
If accelerator pedal is depressed for acceleration
while the opening of the choke valve is small,
the throttle lever pulls down the unloader lever
and the choke valve opens up temporarily for
smooth acceleration.
1. Unloader lever
2. Choke valve
Fig. 4-1-14 Unloader system
Idle Up System
This system operates at idling and compensates
the idle speed;
1) When any one of following electric loads is
operating.
l Small light, tail light, side marker light &
license light
l Rear defogger (if equipped)
l Heater fan
2) When car is at a high altitude (higher than
1,220 m (4,000 ft) and HAC is ON).
3) When temperature in engine room is cold
(below 7°C (44°F) and thermal switch is
ON).
4) When engine speed after engine start is lower
than 1,500 r/min.
The ECM sends an electric signal to the Three
Way Solenoid Valve (TWSV). Receiving the
signal, the TWSV opens its inner valve and
transmits the manifold vacuum to the idle-up
diaphragm. As the diaphragm moves down by
the vacuum, the rod move down and push the
throttle lever to open the throttle valve a little
for the idle-up state.
In this way, the idle-up system helps to stabilize
the idle speed even when electric loads operate.
When electric loads stop operating, the TWSV
closes. Then the idle-up diaphragm as well as
rod moves back up, thus the idle-up state is
released.
I
5 1.
2.
3.
4.5.
8.
7.
8.
Idle-up actuatorAdjusting screw
Diaphragm
Rod
Throttle lever
Throttle valve
Twsv
To intake manifold
Fig. 4- I- 15 Idle-up system operation
4-11 

4) With lights (head light) turned “ON”, check
engine rpm (idle-up speed). Be sure that
heater fan, rear defogger (if equipped), and
air conditioner (if equipped) are all turned
“OFF”.
Idle-up speed900 - 1,000 r/min.
If idle-up speed is not within specification,
adjust by turning adjusting screw.
5) After idle-up adjustment, check to ensure that
idle-up adjusting screw moves as in step 3)
when only heater fan is operated and then
only rear defogger is operated (small light, tail
light, side marker light and license light should
be “OFF” in this cases).
If found faulty in step 3), check following parts
individually according to each procedure.
[Checking TWSV]
1) Make sure that lighting switch, heater fan
switch, rear defogger switch (if equipped) and
air conditioner switch (if equipped) are all
turned OFF.
2) Disconnect TWSV vacuum hoses from intake
manifold and actuator.
With ignition switch at “OFF” position, by
blowing air into hose disconnected from
actuator, make sure there is no continuity
between these hoses.
Turn lighting switch to ON position and by
blowing air into the hose disconnected from
actuator, make sure that there is continuity
between hoses.
Fig. 4- l-45
1. TWSV (Black)2. To intake manifold3. To actuator
[Checking TWSV circuit]
1) Warm up engine to normal operating tempe-
rature.
2) Stop engine and disconnect TWSV coupler.
3) Run engine at idle speed and connect volt-
meter to coupler terminals disconnected.
Check that voltmeter indicates OV.
4) Check that voltmeter indicates about 12V
under either of the following conditions.
0 When engine speed exceeds 2,000 r/min.
l When lighting switch, heater fan switch or
rear defogger switch (if equipped) is turned
ON.
If defective in steps 3) and 4), the particular
circuit is disconnected or in poor contact.
Check the circuit for such condition. For detail,
refer to item “CHECKING IDLE UP SIGNAL”
in SECTION 5 “EMISSION CONTROL SYS-
TEM”.
Fig. 4- l-46
[Checking actuator]
1) Disconnect hose from TWSV.
2) Connect special tool (vacuum pump gauge) to
its hose,
3) Check that actuator rod moves smoothly and
that it is held at the same position when
about 40 cmHg vacuum is applied to actuator.
If rod doesn’t move smoothly, or it isn’t held at
the same position, replace actuator.
If defective in steps 3) and 4), replace TWSV or
checking TWSV circuit.
 4-21 

1. Idle speed adjusting screw
Fig. 4- l-62 Idle speed adjusting screw
4) After idle speed adjustment, check idle-up for
operation with lights (small light, tail light,
side marker light and license light), heater fan
and rear defogger (if equipped) turned “ON”,
only one at a time. Refer to item “Idle Up
Adjustment”. (p. 4-20).
5) Stop engine and check to ensure that accelera-
tor cable play is within the specification as
previously outlined. If play is out of specifica-
tion, adjust it.
Idle Mixture Inspection and Adjustment
[Inspection]
1) Warm up engine to normal operating tem-
perature.
2) Remove seal rubber of duty check coupler
and connect positive terminal of duty meter
to “Blue/Red” wire and negative terminal to
“Black/Green” wire.
1
1. Duty check
3) Set tachometer.
4) Run engine at 1,500 - 2,000 r/min for 30
seconds and bring it to idle speed.
5) Check duty at specified idle speed. If it is out
of specification, adjust it to specification ac-
cording to following adjustment procedure.
Specified DutyIO-50
at 750 - 850 r/min.
After inspection, install seal rubber to duty
check coupler.
[Idle Mixture Adjustment]
The carburetor has been calibrated at the facto-
ry and. should not normally need adjustment in
the field. For this reason, the mixture adjust-
ment should never be changed from the original
factory setting. However, if during diagnosis, the
check indicates the carburetor to be the cause of
a driver performance complaint or emission
failure, or the carburetor is overhauled or
replaced, the idle mixture can be adjusted using
the following procedure.
After adjustment, mixture adjusting screw pin
must be installed.
Idle mixture adjustment procedure is as follows:
1) Remove carburetor from intake manifold
following normal service procedure to gain
access to mixture adjusting screw pin covering
mixture adjusting screw.
2) Drive out mixture adjusting screw pin using
about 4.5 mm (0.18 in) thick iron rod as
shown below.
1. Mixture adjusting screw pin2. Rod
Fig. 4- l-64 Mixture adjusting screw pin
2. Air intake case
Fig. 4- l-63
4-27 

Fig. 5- l-9 ECM
1. ECM
2. Instrument panel.
The ECM sensed parameters are as follows:
l Exhaust Oxygen Concentration.
It is sensed by the oxygen sensor installed on
the exhaust manifold.
1. Oxygen sensor
Fig. 5- I - 7 0Oxygen sensor2. Exhaust manifold
l Engine coolant temperature.
It is sensed by the thermal switch installed on
the intake manifold.
1. Thermal switch
2. Intake manifold
Fig, 5- I- 17Thermal switch
l Throttle position.
It is sensed by the micro switches (wide open
switch and idle switch) installed on the
carburetor.
1. Idle micro switch
2. Wide open micro switch
Fig. 5- 1-12 Micro switches
l Engine speed.
It is computed by the ECM based on the
electrical signal received from the ignition
system.
l Electric load.
The ECM senses electric loads of the follow-
ing items to provide idle speed compensation.
a. Small, tail, side marker, license light.
b. Rear defogger (if equipped).
c. Heater fan.
5-11 
![SUZUKI GRAND VITARA 1987  Service Repair Manual [Checking idle-up signal]
The idle-up system operates when any of the small lights (such as tail light, side marker light and license
light), heater fan and rear defogger is put in operation. If the i SUZUKI GRAND VITARA 1987  Service Repair Manual [Checking idle-up signal]
The idle-up system operates when any of the small lights (such as tail light, side marker light and license
light), heater fan and rear defogger is put in operation. If the i](/manual-img/20/57437/w960_57437-185.png)
[Checking idle-up signal]
The idle-up system operates when any of the small lights (such as tail light, side marker light and license
light), heater fan and rear defogger is put in operation. If the idle-up actuator fails to operate even when
any of such equipments is put in operation, check if signal is sent to the ECM according to the following
procedure.
1) Disconnect the coupler from the ECM.
2) Turn ON the ignition switch but don’t run the engine.
3) Connect a voltmeter between the @ terminal and the body (ground) as shown in below figure. If the
voltmeter indicates 11 - 14V when each equipment is operated individually, it means that idle-up
signal is sent to the ECM.
If the voltmeter does not indicate 11- 14V, the particular circuit is disconnected or in poor contact.
Check the circuit for such conditions.
4) After checking, connect the coupler to ECM securely.
1.Coupler
2. 3.Small Heater lights fan
4. Rear defogger (if equipped)5. Ignition switch (ON)6. Battery
7. Br/Y (Brown/Yellow)
4
&
lead wire
Fig. 5-3-46 Checking idle-up signal
5-35 

Ignition Timing
Ignition timing10” BTDC at
800 * 50 r/min
1 Ignition orderIl-3-4-2I
When checking and adjusting ignition timing,
be sure to use timing light (09900-27301 or
09900-27311).
NOTE:
Prior to check and adjustment of ignition timing,
make sure that head lights, heater fan, rear
defogger (if equipped), and air conditioner (if
equipped) are “OFF”. If any one of these
systems is “ON”,idle up system operates and
engine idle speed will be out of the specification.
[Checking]
1. Remove rubber plug from timing check
window on the transmission case.
2. Start engine and warm it up to normal operat-
ing temperature.
3. After warming up, check to be sure that idle
speed is within specification. If idle speed is
out of specification, adjust it by turning
idle speed adjusting screw of carburetor.
4. Connect timing light to high tension cord of
No. 1 cylinder.
5. With engine running at specified idle speed,
direct the timing light to timing check win-
dow. If 10” BTDC timing mark@on flywheel
appears aligned to timing match mark @ ,
ignition is properly timed.
Fig. 8-20
[Adjusting]
lf ignition timing is out of specification, adjust
it.
Loosen distributor flange bolt and turn distri-
butor housing in place to advance or retard
timing.
Turning housing counterclockwise advances
timing, and vice versa. After adjustment, tighten
flange bolt and recheck timing.
Fig. 8-21
1. Distributor flange bolt
2. Timing is retarded
3. Timing is advanced
Be sure to re-install check window rubber plug
after making above check and adjustment.
WARNING:
When engine is warmed up, exhaust mani-
fold cover and other parts are hot as well.
Be careful not to touch them when remov-
ing and reinstalling rubber plug.
[Checking centrifugal advancer]
After removing distributor cap, turn rotor
clockwise by finger and release it
Check that rotor returns smoothly counterclock-
wise by spring force.
If defective, replace distributor.
Fig. 8-22
8-9 

21-1.COMBINATION METER..................................
21-2.HEAD LIGHT..........................................
21-3.TURN SIGNAL LIGHT AND HAZARD WARNING LIGHT.......
21-4.WINDSHIELD WIPER MOTOR.............................
21-5.WATER TEMPERATURE METER AND GAUGE...............
21-6.FUEL LEVEL METER AND GAUGE........................
21-7.BRAKE WARNING LAMP ...............................
21-8.OIL PRESSURE LAMP..................................
4 WHEEL DRIVE LAMP.................................
21-10. SEAT BELT WARNING LAMP/BUZZER.....................
     ...................
 ...~I-I
.....
21-14. .............................................
21-15. WIRING HARNESS ROUTING............................
21-16. WIRING DIAGRAM....................................
SECTION 21
BODY ELECTRICAL EQUIPMENT
CONTENTS
21-9.
21-11. MAIN SWITCH KEY WARNING BUZZER
21-12. ILUMINATION CONTROLLER..............................................
21-13. REAR DEFOGGER ( hard-top )......................................
FUSE BOX
21-2
21-4 
21-7
21-9
21-11
21-12
21-13
21-14
21-15
21-15
21-16
21-16
21-16
21-18
21-19
21-22
21-1 

21-14. FUSE BOX
The fuses in the fuse box is wired as follows.
Head light (R)
Fuse box
Head light (L)Battery7
Horn, Interior light, Door warning
buzzer, ctock (optional)
Stop light
Hazard warning light-W/GI10AW,YI
Cigarette lighter (optional),
Radio (optional)
-w’B++-B7Ignition coil, Fuel cut solenoid,
TWSV, MCSV, vent solenoid,-B/W15A
3
BIBI-
ECM
Heater blower motor-L9
Rear defogger (optional)-Y/G15A
Wiper motor, washer motor-Y/El15A:: BIBI-
Turn signal light, Back-up light-Y10A
Illumination light, License light,
Meter illumination light
-R’y++lFront position and tail light (RI,
Side marker light (RI--RIG5A:: RIB
Lighting switch
Front position and tail light (L), --R,a,
Side marker light (L)
-t
-c
Mainswitch
Tostarter
B/R--,
-
21-18