1998 OPEL FRONTERA tire pressure

6E–337 ENGINE DRIVEABILITY AND EMISSIONS
0018
Knock Sensor
Insufficient gasoline octane levels may cause detonation
in some engines. Detonation is an uncontrolled explosion
(burn) in the combustion chamber. This uncontrolled
explosion results from a flame front opposite that of the
normal flame front produced by the spark plug. The
rattling sound normally associated with detonation is the
result of two or more opposing pressures (flame fronts)
colliding within the combustion chamber. Light
detonation is sometimes considered normal, but heavy
detonation could result in engine damage.
A knock sensor system is used to control detonation. This
system is designed to retard spark timing up to 20
degrees to reduce detonation in the engine. This allows
the engine to use maximum spark advance to improve
driveability and fuel economy.
The knock sensor system has two major components:
The knock sensor (KS) module.
The knock sensor.
The knock sensor, mounted in the engine block near the
cylinders, detects abnormal vibration in the engine. The
sensor produces an AC output signal of about 10
millivolts. The signal amplitude and frequency are
dependent on the amount of knock being experienced.
The signal voltage increases with the severity of the
knock. This signal voltage is input to the PCM. The PCM
then retards the ignition control (IC) spark timing based
on the KS signal being received.
The PCM determines whether knock is occurring by
comparing the signal level on the KS circuit with the
voltage level on the noise channel. The noise channel
allows the PCM to reject any false knock signal by
indicating the amount of normal engine mechanical noise
present. Normal engine noise varies depending on the
engine speed and load. If the voltage level on the KS
noise channel circuit is below the range considered
normal, DTC P0327 will set, indicating a fault in the KScircuit or the knock sensor. If the PCM determines that an
abnormal minimum or maximum noise level is being
experienced, DTC P0325 will set.
The PCM contains a knock sensor (KS) module. The KS
module contains the circuitry which allows the PCM to
utilize the KS signal and diagnose the KS sensor and the
KS circuitry. If the KS module is missing or faulty, a
continuous knock condition will be indicated, and the
PCM will set DTC P0325.
Although it is a plug-in device, the KS module is not
replaceable. If the KS module is faulty, the entire PCM
must be replaced.
0009
Linear Exhaust Gas Recirculation (EGR)
Control
The PCM monitors the exhaust gas recirculation (EGR)
actual position and adjusts the pintle position accordingly.
The PCM uses information from the following sensors to
control the pintle position:
Engine coolant temperature (ECT) sensor.
Throttle position (TP) sensor.
Mass air flow (MAF) sensor.
Mass Air Flow (MAF) Sensor
The mass air flow (MAF) sensor measures the difference
between the volume and the quantity of air that enters the
engine. “Volume” means the size of the space to be filled.
“Quantity” means the number of air molecules that will fit
into the space. This information is important to the PCM
because heavier, denser air will hold more fuel than
lighter, thinner air. The PCM adjusts the air/fuel ratio as
needed depending on the MAF value. Tech 2 reads the
MAF value and displays it in terms of grams per second
(gm/s). At idle, Tech 2 should read between 4-7 gm/s on a
fully warmed up engine. Values should change quickly on
acceleration. Values should remain stable at any given

ENGINE MECHANICAL 6A – 65
Valve Seat Insert Installation
1. Carefully place the attachment (1) (having a smaller
outside diameter than the valve seat insert) on the
valve seat insert (2).
Legend
(1) Attachment
(2) Valve Seat Insert
(3) Bench Press
NOTE: The smooth side of the attachment must contact
the valve seat insert.
2. Use a bench press (3) to gradually apply pressure
to the attachment and press the valve seat insert
into place.
Note: Do not apply an excessive amount of pressure
with the bench press. Damage to the valve seat insert
will result.
Valve Seat Insert Correction
1. Remove the carbon from the valve seat insert
surface.
2. Use a valve cutter (15°, 45° and 75° blades) to
minimize scratches and other rough areas. This will
bring the contact width back to the standard value.
Remove only the scratches and rough areas. Do
not cut away too much. Take care not to cut away
unblemished areas of the valve seat surface.
Valve Seat Angle: 45°NOTE: Use an adjustable valve cutter pilot.
Do not allow the valve cutter pilot to wobble inside the
valve guide.
3. Apply abrasive compound to the valve seat insert
surface.
4. Insert the valve into the valve guide.
5. Turn the valve while tapping it to fit the valve seat
insert.
6. Check that the valve contract width is correct.
7. Check that the valve seat insert surface is in
contact with the entire circumference of the valve.
3
2 1
012RW055
150
90
30
012RW056
014RS014

ENGINE MECHANICAL 6A – 89
3. Measure the oil clearance between the connecting
rod and the crankshaft.
1) Remove the connecting rod cap nuts and the
rod caps.
Arrange the removed rod caps in the cylinder
number order.
2) Clean the rod bearings and the crankshaft pins.
3) Carefully check the rod bearings.
If even one bearing is found to be damaged or
badly worn, the entire bearing assembly must be
replaced as a set. Reinstall the bearings in their
original positions.
Apply plastigage to the crank pin.
4) Reinstall the rod caps to their original positions.
5) Tighten the cap nuts in 2 steps, using angular
tightening method as shown in the following
specifications.
1st step: 29 Nꞏm (3.0 kgꞏm/22 lb ft)
2nd step: 45°– 60°NOTE: Do not allow the crankshaft to rotate
6) Remove the rod caps.
7) Measure the smallest width of the plastigage
and determine the oil clearance. If the oil
clearance exceeds the limit, replace the rod
bearings as a set.
8) Clean the plastigage from the bearings and the
crankshaft pins
Standard: 0.022 – 0.042 mm (0.0009 – 0.0017 in)
Limit: 0.100 mm (0.0039 in)
REASSEMBLY
1. Connecting Rod
2. Piston
3. Piston Pin
1) Apply a coat of engine oil to the piston pin and
the piston pin hole.
4. Piston Pin Snap Ring
1) Try to insert the piston pin into the piston pin
hole with normal finger pressure.
2) Weight each piston and connecting rod
assembly.
3) Select piston and connecting rod combinations
so that the weight variation of the different four
assemblies is held within the specified limits.
Variance in weight after assembly: Less than 3g
(0.1058 oz)
NOTE: When changing piston/connecting rod
combinations, do not change the piston/piston pin
combination.
4) Attach the piston to the connecting rod with the
piston front mark (2) and the connecting rod
front mark (3) on the same side.
014RW055
012RW075
014RW077

6E–185 4JX1–TC ENGINE DRIVEABILITY AND EMISSIONS
Poor Fuel Economy Symptom
StepActionVa l u e ( s )Ye sNo
1DEFINITION:
Fuel economy, as measured by an actual road test, is
noticeably lower than expected. Also, economy is
noticeably lower than it was on this vehicle at one time,
as previously shown by an actual road test. (Larger than
standard tires will cause odometer readings to be
incorrect, and that may cause fuel economy to appear
poor when it is actually normal.)
Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
—Verify repairGo to Step 3
3Was a visual/physical check performed?
—Go to Step 4
Go to Visual/
Physical
Check
4Check owner’s driving habits.
Is the A/C “ON” full time (defroster mode “ON”)?
Are tires at the correct pressure?
Are excessively heavy loads being carried?
Is acceleration too much, too often?
Is engine oil correct?
Was a problem found?
—Go to Step 5Go to Step 6
5Review the items in Step 4 with the customer and
advise as necessary.
Is the action complete?
—System OK—
61. Visually/physically check: Vacuum hoses for splits,
kinks, and improper connections and routing as
shown on the “Vehicle Emission Control
Information” label.
2. If a problem is found, repair as necessary.
Was a repair required?
—Verify repairGo to Step 7
71. Remove and check the air filter element for dirt or for
restrictions. Refer to
Air Intake System.
2. Replace the air filter element if necessary.
Was a repair required?
—Verify repairGo to Step 8
81. Check for low engine coolant level. Refer to Engine
Cooling
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 9
91. Check for an incorrect or faulty engine thermostat.
Refer to
Engine Cooling.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 10
101. Check for low engine compression. Refer to Engine
Mechanical
.
2. If a problem is found, repair as necessary.
Was a problem found?
—Verify repairGo to Step 11

7A1–52
TRANSMISSION CONTROL SYSTEM (4L30–E)
Conditions For Clearing The DTC/CHECK
TRANS Lamp
The PCM will turn “off” the CHECK TRANS Lamp
after three consecutive ignition cycles without a
failure reported.
The DTC can be cleared from PCM memory by using
a scan tool.
The DTC can also be cleared from memory when the
vehicle has made 40 warmup cycles without a failure
reported.
The PCM will cancel the DTC Actions Taken items
when the fault conditions no longer exist and the
ignition is cycles “off” long enough to power down the
PCM.
Diagnostic Aids
Check for intermittent output speed sensor circuit
problems.
Check for possible incorrect calibration. (PCM part
No., tire specification, and rear axle ratio)
Test Description
The numbers below refer to the step numbers on the
diagnostic chart:
3. This step checks for possible low fluid level causing
slipping resulting in an undefined gear ratio.
4. This step checks for correct gear ratios for
commanded gears.
5. This step checks for low line pressure.
DTC P0730 Transmission Incorrect Gear Ratio
StepActionYe sNo
1Visually inspect the transmission cooling system for fluid leaks.
Refer to Chart 16: Possible Causes of Transmission Fluid
Leaks of Mechanical/Hydraulic Diagnosis Symptoms Index in
Automatic Transmission (4L30–E) section
Was condition found and corrected?
Go to Step 6Go to Step 2
2Refer to Checking Transmission Fluid Level and Condition in
Automatic Transmission (4L30–E) section.
Has transmission fluid checking procedure been performed?
Go to Step 3
Go to Checking
Transmission
Fluid Level and
Condition in
Automatic
Transmission
(4L30–E) section
31. Install the scan tool.
2. Turn the ignition switch to the “on” position.
3. Engine not running.
NOTE: Before clearing DTC(s) use the scan tool to record the
“Failure Records” for reference, as data will be lost when the “Clear
Info” function is used.
4. Record the Failure Record data.
5. Use the scan tool snapshot mode to record transmission gear
ratios.
6. Drive vehicle in transmission gear ranges 1, 2, 3, and D with
the engine speed is greater than 3,500 rpm for 5.5 seconds.
7. Record each transmission gear.
1st:2.73 – 2.99
2nd:1.54 – 1.71
3rd:0.93 – 1.05
4th:0.66 – 0.78
Does commanded gear ratio match ranges as shown?
Refer to
Diagnostic Aids
Go to Step 4
4Perform line pressure check.
Refer to Line Pressure Test in Automatic Transmission
(4L30–E) section.
Was condition found and corrected?
Go to Step 6Go to Step 5

CLUTCH7C–11
1. Use a straight edge and a feeler gauge to measure
the pressure plate friction surface flatness in four
directions.
2. If any of the measured values exceeds the specified
limit, the pressure plate must be replaced.
Pressure Plate Warpage
Limit: 0.3 mm (0.012 in)
Clutch Cover
201RS004
1. Visually check the entire clutch cover for excessive
wear, cracking, and other damage.
2. The clutch cover must be replaced if any of these
conditions are present.
Clutch Set Force
201RS005
1. Invert the pressure plate assembly.2. Place a new driven plate over the pressure plate. A
metal sheet with “A” thickness of 8.3 mm (0.327 in)
may be used in place of the driven plate.
3. Compress the pressure plate assembly until the
distance “B” becomes 12 mm (0.472 in).
4. Note the pressure gauge reading.
5. If the measured value is less than the specified limit,
the pressure plate assembly must be replaced.
Clutch Set Force
Standard: 7208 N ( 1621 lb)
Limit: 6468 N (1454 lb)
Diaphragm Spring Finger Height
201RW009
Legend
(1) Release Side
1. Place a new driven plate or a 8.3 mm (0.327 in)
spacer beneath the pressure plate.
2. Fully compress the pressure plate and diaphragm
spring.
3. There are two ways to do this.
4. Use a bench press to press down on the assembly
from the top.
5. Tighten the fixing bolts.
NOTE: Preload on diaphragm spring finger must be 49 –
98 N (11 – 22 lb) in direction of release, when clutch cover
assembly is bolted to the flywheel.
6. Measure the spring height from base to spring tip “A”.
If the measured value exceeds the specified limit, the
pressure plate assembly must be replaced.
Diaphragm Spring Finger Height
Standard: 49.9 mm – 51.9 mm (1.965 in –
2.043 in)

8A–4LIGHTING SYSTEM
Headlight
Headlight and Associated Parts
801RW003
Legend
(1) Radiator Grille
(2) Front End Lower Panel
(3) Headlight Assembly
(4) Headlight(5) Headlight Rim
(6) Headlight Bulb
(7) Rear Cover
(8) Bracket
(9) Front Combination Light
Removal
1. Disconnect the battery ground cable.
2. Remove the screw and pull out the two projecting
portions on the fender to remove the front
combination light.
3. Remove five clips and two screws to remove the
radiator grille.
4. Remove two screws to remove the front end lower
panel(2).
5. Remove two bolts and two nuts to remove the
headlight assembly (with bracket).
6. Remove the headlight bulb.
7. Remove two screws, two nuts and the spring for the
headlight aim adjustment to remove the bracket.
8. Remove four screws to remove the rear cover.
9. Remove the headlight rim.
10. Remove the headlight.
Installation
To install, follow the removal steps in the reverse order.
CAUTION: After installing the headlight, be sure to
adjust the headlight aim.
Headlight Adjustment
Preparation
Place the unloaded vehicle on a level surface and check
to see if the inflation pressure of the tires is correct, the
lenses are clean, and the battery is sufficiently charged.
Adjust the aim with the headlight tester, if necessary.
When adjusting, follow the procedure of the tester
manufacturer’s.
801RS009

DIFFERENTIAL (REAR 220mm)
4A2A–3
Diagnosis
Many noises that seem to come from the rear axle
actually originate from other sources such as tires, road
surface, wheel bearings, engine, transmission, muffler, or
body drumming. Investigate to find the source of the
noise before disassembling the rear axle. Rear axles, like
any other mechanical device, are not absolutely quiet but
should be considered quiet unless some abnormal noise
is present.
To make a systematic check for axle noise, observe the
following:
1. Select a level asphalt road to reduce tire noise and
body drumming.
2. Check rear axle lubricant level to assure correct level,
and then drive the vehicle far enough to thoroughly
warm up the rear axle lubricant.
3. Note the speed at which noise occurs. Stop the
vehicle and put the transmission in neutral. Run the
engine speed slowly up and down to determine if the
noise is caused by exhaust, muffler noise, or other
engine conditions.
4. Tire noise changes with different road surfaces; axle
noises do not. Temporarily inflate all tires to 344 kPa
(3.5kg/cm
2, 50 psi) (for test purposes only). This will
change noise caused by tires but will not affect noise
caused by the rear axle.
Rear axle noise usually stops when coasting at
speeds under 48 km/h (30 mph); however, tire noise
continues with a lower tone. Rear axle noise usually
changes when comparing pull and coast, but tire
noise stays about the same.
Distinguish between tire noise and rear axle noise by
noting if the noise changes with various speeds or
sudden acceleration and deceleration. Exhaust and
axle noise vary under these conditions, while tire
noise remains constant and is more pronounced at
speeds of 32 to 48 km/h (20 to 30 mph). Further check
for tire noise by driving the vehicle over smooth
pavements or dirt roads (not gravel) with the tires at
normal pressure. If the noise is caused by tires, it will
change noticeably with changes in road surface.
5. Loose or rough front wheel bearings will cause noise
which may be confused with rear axle noise; however,
front wheel bearing noise does not change when
comparing drive and coast. Light application of the
brake while holding vehicle speed steady will often
cause wheel bearing noise to diminish. Front wheel
bearings may be checked for noise by jacking up the
wheels and spinning them or by shaking the wheels to
determine if bearings are loose.
6. Rear suspension rubber bushings and spring
insulators dampen out rear axle noise when correctly
installed. Check to see that there is no link or rod
loosened or metal–to–metal contact.
7. Make sure that there is no metal–to–metal contact
between the floor and the frame.
After the noise has been determined to be in the axle, the
type of axle noise should be determined, in order to make
any necessary repairs.
Gear Noise
Gear noise (whine) is audible from 32 to 89 km/h (20 to 55
mph) under four driving conditions.
1. Driving under acceleration or heavy pull.
2. Driving under load or under constant speed.
3. When using enough throttle to keep the vehicle from
driving the engine while the vehicle slows down
gradually (engine still pulls slightly).
4. When coasting with the vehicle in gear and the throttle
closed. The gear noise is usually more noticeable
between 48 and 64 km/h (30 and 40 mph) and 80 and
89 km/h (50 and 55 mph).
Bearing Noise
Bad bearings generally produce a rough growl or grating
sound, rather than the whine typical of gear noise.
Bearing noise frequently “wow–wows” at bearing rpm,
indicating a bad pinion or rear axle side bearing. This
noise can be confused with rear wheel bearing noise.
Rear Wheel Bearing Noise
Rear wheel bearing noise continues to be heard while
coasting at low speed with transmission in neutral. Noise
may diminish by gentle braking. Jack up the rear wheels,
spin them by hand and listen for noise at the hubs.
Replace any faulty wheel bearings.
Knock At Low Speeds
Low speed knock can be caused by worn universal joints
or a side gear hub counter bore in the cage that is worn
oversize. Inspect and replace universal joints or cage and
side gears as required.
Backlash Clunk
Excessive clunk on acceleration and deceleration can be
caused by a worn rear axle pinion shaft, a worn cage,
excessive clearance between the axle and the side gear
splines, excessive clearance between the side gear hub
and the counterbore in the cage, worn pinion and side
gear teeth, worn thrust washers, or excessive drive pinion
and ring gear backlash. Remove worn parts and replace
as required. Select close–fitting parts when possible.
Adjust pinion and ring gear backlash.