driver seat adjustment ISUZU TROOPER 1995 Workshop Manual

3-10 DIAGNOSIS
RADIAL TIRE WADDLE (Fig. 3-4)
Fig. 3-4
Waddle is side-to-side
movement at the front and/or
rear of the car. It can be caused by the steel belt not
being straight within the tire, or by excessive lateral
runout of the tire or wheel. It is most noticeable at low
speed, about 8 to 48 km/h (5 to 30 mph). It may also
cause
rough ride at 80 to 113 km/h (50 to 70 mph).
The car can be road tested
to see which end of the car
has
the faulty tire. If the tire causing the waddle is on
the rear, the rear end
of the car will "waddle". From
the
driver's seat, it feels as if someone is pushing on
the side
of the car.
If the faulty tire is on the front, the waddle is more
easily seen. The front sheet metal appears to be
moving back and forth. It feels as if the driver's seat
is
the pivot point in the car.
Another more time-consuming method of
determining the faulty tire is substituting tire and
wheel assemblies
that are known to be good. Follow
these steps:
1. Drive the car to determine if the waddle is
coming from the front or rear.
2. Install tire and wheel assemblies known to be
good (from a similar car) in place ofthose on the
end
of the car which is waddling. If the waddle
cannot be isolated to front or rear, start with the
rear tires.
3. Road test again. If improvement is noted, install
the original tire and wheel assemblies one at a
time until the faulty tire is found. If no
improvement is noted, install tires known to be
good in place of all four. Then, install the originals
one at a
time until the faulty tire is found.
RADIAL TIRE LEAD/PULL (Fig. 3-5)
"Lead/Pull" is vehicle deviation from a straight path,
on a level road
with no pressure on the steering
wheel.
Lead is usually caused by:
1. Poorly manufactured radial tires.
2. Uneven brake adjustment.
3. Wheel alignment.
The
way in which a tire is built can produce lead in a
car.
An example of this is placement of the belt. Off­
center belts on radial tires can cause the tire to
develop a side force while rolling straight down the
road and the tire will tend to roll like a cone.
The
"Radial Tire Lead/Pull Correction" chart (Fig. 3-5)
should be used to make sure that front wheel
alignment is not mistaken for tire lead.
Rear
tires will not cause lead/pull.
II

6E2 120 DRIVEABILITY AND EMISSIONS
THROTTLE BODY (TB) ASSEMBLY
The Throttle Body (TB) assembly is attached to the
intake manifold air
plenum, and is used to control air
flow into the engine, thereby controlling engine output
(Fig. 6E2-73). The TB within the TB is opened by the
driver through the accelerator controls. During engine
idle, the
TB is almost closed, and air flow control is
handled by the Idle Air Control (lAC) valve, described
below. To prevent
TB icing during cool weather
operation, engine
coolant is directed through a engine
coolant tube, part
of the TB, the engine coolant then
circulates through internal passageways around the
throttle bore and returns via the return engine coolant
tube.
The
TB also provides the location for mounting the
Throttle Position
Sensor. Vacuum ports the located at,
above or
below the throttle body to generate vacuum
signal needed
by various components.
Idle Air Control (lAC) Valve
Engine idle speed is controlled by the Engine Control
Module (ECM) through the Idle Air Control (lAC) valve
mounted on the
TB. The ECM sends voltage pulses to
the lAC motor windings causing the lAC valve pintle to
move "IN" or "OUT" a given distance (a step or count)
for each pulse. The pintle movement controls the
airflow around the TBs, which in turn, controls engine
idle speed.
• The "controlled" or desired idle speed for all
engine operating conditions is programmed into
the
calibration of the ECM. The programmed
engine speeds are based on engine coolant
temperature, park/neutral position switch status,
vehicle speed, battery positive voltage, and air
conditioning pressure (if equipped).
• The ECM "learns" the proper lAC valve positions to
achieve warm, stabilized idle speeds (revolution
per minute), desired
for the various conditions
(Park/Neutral position
or Drive, air conditioning
"ON" or "OFF", if equipped). This information is
stored in
ECM "Keep Alive" memories
(information
is retained after ignition is "OFF"). All
other lAC valve positioning is calculated based on
these
memory values.
As a
result, engine variations due to wear and
variations in
minimum TB position (within limits)
do not affect engine idle speeds. This system
provides correct idle control under
all conditions.
This also means
that disconnecting power to the
ECM can result in incorrect idle control or
necessity to partially depress the accelerator
pedal
when starting until the ECM relearns idle
control. Refer to note regarding clearing
memory
in "ECM and Sensors," Section "6E2-C1 ".
•
Engine idle speed is a function of total airflow into
the engine based on
lAC valve pintle position plus
TB opening plus calibrated vacuum loss through
accessories.
• The minimum TB position is set at the factory with
a stop screw. This setting allows enough air flow
by the TB to cause the lAC valve pintle to be
positioned a calibrated
number of steps (counts),
from the seat, during "controlled" idle operation.
The
minimum TB position setting on this engine
should not be considered the
"minimum idle
speed", as on other fuel injected engines. The
throttle stop
screw is covered with a plug at the
factory
following adjustment.
U7 CAUTION:
VI Do not attempt to remove the protective cap and
readjust the stop screw before
reviewi~g t~e
"Minimum TB Position Check", later m th1s
section. Misadjustment may result in damage to
the lAC valve or TB.
Fig. 6E2-73
2. Throttle body assembly
3. Throttle position sensor (TPS)
• The ECM normally resets the lAC valve pintle
position once during each ignition cycle,
when
vehicle speed increases above 35 miles per hour
on moderate acceleration. During the reset, the
ECM commands the lAC valve pintle to retract
completely, then move
"IN" to the seated position
(to establish the zero
count position), and then
back
out to the desired position. If, after the reset,
the
ECM is able to control the idle speed within the
calibrated count range, the
lAC valve will not be
reset again until the ignition has been turned
"OFF", the engine restarted and the car then
driven above 35 mile per hour.
If the ECM is not
able to control idle speed within the calibrated
count range after the first reset, the
ECM assumes
the
lAC valve pintle position is "lost", and enables
another reset
to occur. This will continue until the
pintle position is relearned.
• If the lAC valve is suspected as being the cause of
improper idle speed, perform a functional check of
the lAC valve (CHART C-2C) as described later in
this section.
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