check engine SUZUKI GRAND VITARA 1987 Service Owner's Guide

REMOVAL AND INSTALLATION
Removal and installation of carburetor
place where no fire is used around.
Removal
1) Disconnect negative battery cord from
battery.
2) Drain coolant.
WARNING:
To help avoid the danger of being burned,
do not remove the drain plug and the
radiator cap while the engine and radiator
are still hot. Scalding fluid and steam can
be blown out under pressure if the plug
and cap are taken off too soon.
3) Remove air intake case from carburetor.
4) Disconnect micro switches, switch vent sole-
noid valve, fuel cut solenoid valve and MCSV
lead wires at their couplers.
5) Disconnect VSV coupler from VSV.
6) Detach bracket with EGR modulator and
TWSV from carburetor.
1. Bracket3.EGRmodulator2. Twsv
Fig. 4- 1-16
7) Disconnect water inlet and outlet hoses from
carburetor.
8) Disconnect accelerator cable from carburetor.
9) Disconnect vacuum hoses from idle up
actuator and carburetor.
10) To release the pressure in fuel tank, remove
fuel tank filler cap and then, reinstall it.
11) Disconnect fuel inlet hose from carburetor.
12) Check all around carburetor for any other
parts required to be removed or disconnect-
ed for removal of carburetor and remove or
disconnect whatever necessary.
13) Remove carburetor from intake manifold.
Fig. 4- 7- 17
Installation
Install in the reverse order of removal using care
for the following.
l Install carburetor to intake manifold.
Tighten 4 carburetor nuts to the specified
torque.
Tightening torque
for nuts13.5 - 20.0 lb-ft
l Connect water hoses to carburetor.
1. Carburetor
Fig. 4- I- 18
2. Inlet hose3. Outlet hose
4-12

0 Connect electric couplers securely.
l Connect accelerator cable to carburetor. With
the accelerator pedal released, adjust the cable
play to specification. This adjustment can be
made by turning the adjusting nut. After
adjustment, tighten the lock nut. Refer to
p. 4-19.
l Connect vacuum hoses securely.
l Refill cooling system.
l Connect negative cable at battery.
NOTE:
Upon completion of installation, be sure to
check each part for evidence of fuel leakage and
for proper operation. If defective, correct..
UNIT REPAIR OVERHAUL
This section outlines procedure to be used for
overhauling carburetor as removed from engine.
For removal and installation of carburetor from
and to engine, refer to the previous page.
NOTE:
l Be sure to replace gaskets as well as worn or
damaged parts.
l While disassembling and assembling carbure-
tor, use special care not to deform levers on
throttle valve shaft or cause damage to any
other parts.
l Don’t disassemble mixture control solenoid
valve and accelerator pump piston.
l Don’t remove idle and wide open micro
switches from the bracket where they are
installed.
Disassembly
1) Turn fast idle cam counterclockwise and
insert a pin avialable into holes on cam and
bracket to lock the cam.
Fig. 4- I- 19
1. Fast idle cam
2. Bracket3. Pin
4-13

16) Clamp wire harness securely.MAINTENANCE SERVICES
Fig. 4- l-39
1. Clamp
17) Remove the pin installed before disassemb-
ly (to lock fast idle cam).
Fig. 4- l-40
Before checking or adjusting the carburetor as
the cause of poor engine performance or rough
idle, check the followings for malconditions.
Ignition system including distributor, timing,
spark plugs and wires.
Air cleaner including thermostatically control-
led air cleaner system.
Evaporative emission control system.
PCV system.
EG R valve.
Engine compression.
Also, check the intake manifold, carburetor and
vacuum hoses for leakage.
Accelerator Cable Adjustment
Check accelerator cable for play and adjust if
necessary.
Cable play should be within the specifications. If
out of specification, loosen lock nut and adjust
by turning adjusting nut. Be sure to tighten lock
nut securely after adjustment.
Condition
When carburetor and
coolant are cold;
When carburetor and
coolant are warm;
Cable play
10 - 15 mm
(0.4 - 0.6 in.)
3-5mm
(0.12 - 0.20 in.)
1. Accelerator cable
2. Cable play
3. Lock nut
4. Adjusting nut
Fig. 4- l-4 1 Accelerator cable play
4-19

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

Ambient temperatureClearance
Fig. 4-l-47
Choke Adjustment
Perform following check and adjustments with
air intake case removed when engine is cold.
[Choke valve]
1) Check choke valve for smooth movement by
pushing it with a finger.
Fig. 4-l-48 Choke valve
2) Make sure that choke valve is closed almost
completely when ambient temperature is
below 25°C (77” F) and engine is cold.
3) Check to ensure that choke valve to carbure-
tor bore clearance is within following specifi-
cations when engine is cool.
I.6 mmC&n*?.:.. \
NOTE:
As ambient temperature or engine coolant
temperature rises high, clearance increases.
1. Choke valve2. Thickness gauge
Fig. 4- 149 Choke valve to carbure tar bore
clearance
4) If clearance is found excessively large or
small in the above check, check strangler
spring, choke piston and each link in choke
system for smooth operation. Lubricate
choke valve shaft and each link with spray
lubricant if necessary.
Fig. 4-l-50
4-22

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

1.Vacuum (Apply-30w-50cmHgvacuum)
2. Choke piston rod3.Screw driver
4. Choke valve to carburetor bore clearance
Fig. 4- l-54 Moving choke piston rod
Fast Idle Adjustment
NOTE:
Fast idle check and adjustment should be per-
formed after making sure of the following.
l Ambient temperature is between 22°C and
28°C (71°F and 82°F).
*Idle up system (idle up speed) is normal.
Check and adjustment procedure is as follows.
1) Leave car at a place where ambient tempe-
rature is between 22°C and 28°C (71°F and
82”F), for over 4 hours.
NOTE:
When carburetor is removed, leave carburetor at
the place mentioned above for an hour and
check as follows.
2) After leaving, make sure that the mark on
cam and the center of cam follower are in
alignment as shown in below figure.
Fast idle cam
Mark on cam
Cam follower
3) Disconnect vacuum hose from TWSV and
connect special tool (vacuum pump gauge) to
its hose.
,
1.2.
3.4.
5.
6.7.
8.
Twsv
Vacuum hose
Idle up actuatorClearanceActuator rodIdle up adjusting screwFast idle adjusting screw
Special tool (Vacuum pump gauge)
With applying about 40 cmHg vacuum to
actuator.
4) Check clearance between actuator rod and
idle up adjusting screw.
Clearance “4”
for fast idle
2.5 - 3.0 mm
(O.lO- 0.12 in.)
If clearance is out of specification, adjust it
to specification with tast idle adjusting screw-
Unloader Adjustment
Perform this check and adjustment when engine
is cool.
1) Remove air intake case.
2) Make sure that choke valve is fully closed.
3) Fully open throttle valve and check choke
valve to carburetor bore clearance to ensure it
is within following specification.
Fig. 4- l-55 Mark on cam and cam follower
4-24

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