1987 SUZUKI GRAND VITARA light

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

Float Adjustment
l)The fuel level in float chamber should be
within round mark at the center of level
gauge.
1. Level gauge
2. Round mark3. Fuel level
Fig. 4- l-42 Fuel level
2) If the fuel level is not found within the round
mark, check the float level and adjust it as
follows:
a) Remove the air horn, and invert it.
b) Measure the distance between the float and
the gasketed surface of air horn. The
measured distance is float level, and it
should be the specification.
If the float level is out of specification,
adjust it by bending the tongue up or
down.
NOTE:
l This measurement should be made without a
gasket on the air horn.
l Check float height with float weight applied
to needle valve.
l As a gauge for checking float level, use
something whose thickness measurement is
the same as specified level measurement
(such as a drill or M8 bolt) after confirming
thickness with vernier calipers.
Float level8mm
specification(0.31 in.)
.
Fig. 4- l-43 Float level
1. Air horn
2. Float
3. Float level
4. Tongue
Idle Up Adjustment
1) Warm up engine to normal operating tempe-
rature.
2)Check to be sure that engine idle speed is
specification.
3) Check to ensure that idle-up actuator rod
moves down (indicating that idle-up is at
work) when small light, tail light, license
light and side marker light are turned “ON”.
1. Idle-up actuator
2. Idle-up actuator rod
3. Choke piston
4. Idle up adjustingsorew
Fig. 4- l-44 Idle-up adjusting screw
4-20

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

5) If clearance is still out of specification even
after lubrication in step 4), remove carburetor
from intake manifold and remove idle-up
actuator from carburetor.
Then, turn fast idle cam counterclockwise and
insert a pin available into holes in cam and
bracket to lock the cam.
In this state, bend choke lever shown in below
figure up or down, with plier. Bending up
causes choke valve to close, and down to
open.
1. Fast idle cam 3. Pin2. Bracket4. Choke lever
Fig. 4- l-51 Choke lever
6) After installing air intake case, start engine
again and warm it up fully.
7)Stop the engine when it is warmed up and
remove air intake case again, and then check
to ensure that choke valve is fully open.
Fig. 4- l-52
[Choke piston]
Check choke piston as follows.
1) Disconnect choke piston hose at throttle
chamber.
2) With choke valve pushed down to its closing
side lightly by finger, apply vacuum,to choke
piston hose with vacuum pump gauge, and
check to ensure that choke valve to carbure-
tor bore clearance is within the specification.
Choke valve to carbu-1.1 - 1.3 mm
retor bore clearance(0.04 - 0.05 in.)
6
2
4
3/
1. Choke piston hose
2.Chokepiston
3. Vacuum (Apply -30 w-50 cm Hg vacuum)4.Chokevalve
5. Push here lightly
6. Choke valve to carburetor bore clearance
Fig. 4- l-53 Checking choke piston
3) With vacuum appliedas in step 2), move choke
piston rod with small screw driver as shown
and check to ensure that choke valve to car-
buretor bore clearance is within following
specification.
Choke valve to carbu-3.2 - 3.7 mm
retor bore clearance(0.13 - 0.14 in.)
If choke valve doesn’t open fully, defect lies in
wax-element or its link system.
Repair or replace defective parts(s).
4-23

With vacuum pump gauge set at Black side of
VTV, when pump is operated, pointer moves
considerably but moves back to zero position as
soon as pump operation is stopped.
Brown side
(Actuator side) Black side
Fig. 4-l-60
1. VTV
2. Vacuum pump gauge
install VTV. Refer to Fig. 4-l -2 for installation.
[ VSV (Vacuum Switching Valve)]
1) Disconnect VSV vacuum hoses from 3 way
joint and secondary actuator and while
blowing either hose, check that air doesn’t
come out of the other hose.
2) Turn on ignition switch and depress accelera-
tor pedal fully. 5 or 6 seconds later, while
blowing either vacuum hose, check that air
comes out of the other hose.
J5
Fig. 4- l-61
1I
1. vsv4. WOTS
2. Ignition switch5. ECM
3. Battery6. Blow air
If check results in steps 1) and 2)are not satisfac-
tory, either replace VSV or check WOTS and its
circuit referring to SECTION5 “EMISSION
CONTROL SYSTEM”.
Idle Speed Adjustment
NOTE:
Before starting engine, place transmission gear
shift lever in “Neutral”, and set parking brake
and block drive wheels.
Before idle speed check and adjustment, make
sure of the following.
l Lead wires and hoses of engine emission
control systems are connected securely.
l Accelerator cable has some play, that is, it is
not tight.
l All vacuum hoses are connected securely.
l Fuel level should be within round mark at the
center of level gauge.
l Valve lash is checked and adjusted according
to the maintenance schedule.
l Air cleaner has been properly installed and is
in good condition.
l All accessories (wipers, heater, lights, etc) are
out of service.
l Ignition timing is within specification.
l Idle up actuator is not operating when engine
is running at idle speed.
NOTE:
In areas above 4,00Ofeet( 1,220m) elevation
(high altitude), idle up system will be normally
in operation. Do not attempt to adjust the idle
speed.
After above items are all confirmed, adjust idle
speed as follows.
1) Warm up engine to normal operating tempe-
rature.
2) Check to ensure that idle speed is within
750 - 850 r/min (rpm).
3) If idle speed is not within specified range,
adjust by turning idle speed adjusting screw.
If idle speed can not be adjusted to the speci-
fication by turning the adjusting screw, it can
be due to faulty return of throttle valve or
some other reason. Determine cause and
repair, and then adjust idle speed to specifica-
tion.
4-26

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

3) Reinstall carburetor following normal service
procedures.
Connect emission control system hoses and
lead wires. Make specified play on accelerator
cable and refill cooling system.
4) Place transaxle gear shift lever in “Neutral”,
set parking brake and block drive wheels.
5) Start engine, and warm it up to normal
operating temperature, stop engine.
6) Be sure to check the following before idle
mixture adjustment.
l Fuel level is within round mark at the
center of level gauge.
l Valve lash is checked and adjusted accord-
ing to the maintenance schedule.
l Air cleaner has been properly installed
and is in good condition.
l All accessories (wipers, heater, lights etc)
are out of service.
l Ignition timing is within specification.
l Choke valve opens fully.
l Idle-up actuator does not operate.
7) Check and adjust idle speed to specification
if necessary.
8) 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.
9) Run engine at 1,500 - 2,000 r/min for 30
seconds and bring it to idle speed.
10) With engine running at idle speed, adjust idle
mixture adjusting screw slowly in small incre-
ment allowing time for duty to stabilize after
turning screw to obtain duty of 10 - 50.
If duty is too low, back screw out; if too
high, screw it in. After obtaining duty of
10 - 50, recheck idle speed, and adjust if
necessary.
NOTE:
If adjustment can’t be made because duty meter
indicator does not deflect, check feed back
system according to the checking procedure of
system described in section of Emission Control
System.
11) After adjustment, install seal rubber to duty
check coupler and drive in idle mixture
adjusting screw pin.
4-28

Fuel Pulp
A mechanical fuel pump is mounted on the
cylinder head.
The diaphragm in fuel pump is actuated from
the cam on the engine camshaft, through a fuel
pump rod and a rocker arm of fuel pump. A
rocker arm rides on the cam through the fuel
pump rod and moves the pump diaphragm up
and the fuel pump feeds the fuel into carburetor.
A fuel return circuit is provided in this pump in
order to avoid “vapor lock”. When the float
chamber refuses to admit fuel, a slight pressure
buildup occurs on the discharge side of the
pump and this buildup causes the fuel to flow
through the return circuit to the fuel tank. In
other words, the fuel pump is kept in action as
long as the engine is running, so that the con-
stant flow of fuel through the pump keeps it
cool.
2
Fig. 4-2-8
Fig. 4-2-6
Fuel Filter
Fuel filter is located at the front part of fuel
tank, inside the right-hand side of chassis.
Fuel enters the filter through its inlet hose and,
after passing through filtering element, comes
out of its outlet hose communicated to the fuel
pump. This filter is not meant to be disassem-
bled. It is of cartridge type, consisting of a
filtering element in a plastic case.
1
1. Fuel pump
2. inlet hose
3. Outlet hose4. Return hose
6
1. Inlet
2. Outlet
Fig. 4-2-9
1.Inlet
2.Outlet
3.Return tube
4.inlet valve
5.Outlet valve
6.Diaphragm
7.Rocker arm
8.Fuel pump rod
Fig. 4-2-7
4-32