air condition OPEL FRONTERA 1998 Workshop Manual

6E–347 ENGINE DRIVEABILITY AND EMISSIONS
the secondary ignition circuit to flow through the spark
plug to the ground.
TS24047
Ignition Control PCM Output
The PCM provides a zero volt (actually about 100 mV to
200 mV) or a 5-volt output signal to the ignition control (IC)
module. Each spark plug has its own primary and
secondary coil module (”coil-at-plug”) located at the spark
plug itself. When the ignition coil receives the 5-volt signal
from the PCM, it provides a ground path for the B+ supply
to the primary side of the coil-at -plug module. This
energizes the primary coil and creates a magnetic field in
the coil-at-plug module. When the PCM shuts off the
5-volt signal to the ignition control module, the ground
path for the primary coil is broken. The magnetic field
collapses and induces a high voltage secondary impulse
which fires the spark plug and ignites the air/fuel mixture.
The circuit between the PCM and the ignition coil is
monitored for open circuits, shorts to voltage, and shorts
to ground. If the PCM detects one of these events, it will
set one of the following DTCs:
P0351: Ignition coil Fault on Cylinder #1
P0352: Ignition coil Fault on Cylinder #2
P0353: Ignition coil Fault on Cylinder #3
P0354: Ignition coil Fault on Cylinder #4
P0355: Ignition coil Fault on Cylinder #5
P0356: Ignition coil Fault on Cylinder #6
Knock Sensor (KS) PCM Input
The knock sensor (KS) system is comprised of a knock
sensor and the PCM. The PCM monitors the KS signals
to determine when engine detonation occurs. When a
knock sensor detects detonation, the PCM retards the
spark timing to reduce detonation. Timing may also be
retarded because of excessive mechanical engine or
transmission noise.
Powertrain Control Module (PCM)
The PCM is responsible for maintaining proper spark and
fuel injection timing for all driving conditions. To provideoptimum driveability and emissions, the PCM monitors
the input signals from the following components in order
to calculate spark timing:
Engine coolant temperature (ECT) sensor.
Intake air temperature (IAT) sensor.
Mass air flow (MAF) sensor.
PRNDL input from transmission range switch.
Throttle position (TP) sensor.
Vehicle speed sensor (VSS) .
Crankshaft position (CKP) sensor.
Spark Plug
Although worn or dirty spark plugs may give satisfactory
operation at idling speed, they frequency fail at higher
engine speeds. Faulty spark plugs may cause poor fuel
economy, power loss, loss of speed, hard starting and
generally poor engine performance. Follow the
scheduled maintenance service recommendations to
ensure satisfactory spark plug performance. Refer to
Maintenance and Lubrication.
Normal spark plug operation will result in brown to
grayish-tan deposits appearing on the insulator portion of
the spark plug. A small amount of red-brown, yellow, and
white powdery material may also be present on the
insulator tip around the center electrode. These deposits
are normal combustion by-products of fuels and
lubricating oils with additives. Some electrode wear will
also occur. Engines which are not running properly are
often referred to as “misfiring.” This means the ignition
spark is not igniting the air/fuel mixture at the proper time.
While other ignition and fuel system causes must also be
considered, possible causes include ignition system
conditions which allow the spark voltage to reach ground
in some other manner than by jumping across the air gap
at the tip of the spark plug, leaving the air/fuel mixture
unburned. Misfiring may also occur when the tip of the
spark plug becomes overheated and ignites the mixture
before the spark jumps. This is referred to as
“pre-ignition.”
Spark plugs may also misfire due to fouling, excessive
gap, or a cracked or broken insulator. If misfiring occurs
before the recommended replacement interval, locate
and correct the cause.
Carbon fouling of the spark plug is indicated by dry, black
carbon (soot) deposits on the portion of the spark plug in
the cylinder. Excessive idling and slow speeds under
light engine loads can keep the spark plug temperatures
so low that these deposits are not burned off. Very rich
fuel mixtures or poor ignition system output may also be
the cause. Refer to DTC P0172.
Oil fouling of the spark plug is indicated by wet oily
deposits on the portion of the spark plug in the cylinder,
usually with little electrode wear. This may be caused by
oil during break-in of new or newly overhauled engines.
Deposit fouling of the spark plug occurs when the normal
red-brown, yellow or white deposits of combustion by
products become sufficient to cause misfiring. In some
c a s e s , t h e s e d e p o s i t s m a y m e l t a n d f o r m a s h i n y g l a z e o n
the insulator around the center electrode. If the fouling is
found in only one or two cylinders, valve stem clearances
or intake valve seals may be allowing excess lubricating

6E–348
ENGINE DRIVEABILITY AND EMISSIONS
oil to enter the cylinder, particularly if the deposits are
heavier on the side of the spark plug facing the intake
valve.
TS23995
Excessive gap means that the air space between the
center and the side electrodes at the bottom of the spark
plug is too wide for consistent firing. This may be due to
improper gap adjustment or to excessive wear of the
electrode during use. A check of the gap size and
comparison to the gap specified for the vehicle in
Maintenance and Lubrication will tell if the gap is too wide.
A spark plug gap that is too small may cause an unstable
idle condition. Excessive gap wear can be an indication
of continuous operation at high speeds or with engine
loads, causing the spark to run too hot. Another possible
cause is an excessively lean fuel mixture.
TS23992
Low or high spark plug installation torque or improper
seating can result in the spark plug running too hot and
can cause excessive center electrode wear. The plug
and the cylinder head seats must be in good contact for
proper heat transfer and spark plug cooling. Dirty or
damaged threads in the head or on the spark plug cankeep it from seating even though the proper torque is
applied. Once spark plugs are properly seated, tighten
them to the torque shown in the Specifications Table. Low
torque may result in poor contact of the seats due to a
loose spark plug. Overtightening may cause the spark
plug shell to be stretched and will result in poor contact
between the seats. In extreme cases, exhaust blow-by
and damage beyond simple gap wear may occur.
Cracked or broken insulators may be the result of
improper installation, damage during spark plug
re-gapping, or heat shock to the insulator material. Upper
insulators can be broken when a poorly fitting tool is used
during installation or removal, when the spark plug is hit
from the outside, or is dropped on a hard surface. Cracks
in the upper insulator may be inside the shell and not
visible. Also, the breakage may not cause problems until
oil or moisture penetrates the crack later.
TS23994
A broken or cracked lower insulator tip (around the center
electrode) may result from damage during re-gapping or
from “heat shock” (spark plug suddenly operating too
hot).
TS23993

6E–349 ENGINE DRIVEABILITY AND EMISSIONS
Damage during re-gapping can happen if the gapping
tool is pushed against the center electrode or the
insulator around it, causing the insulator to crack.
When re-gapping a spark plug, make the adjustment
by bending only the ground side terminal, keeping the
tool clear of other parts.
”Heat shock” breakage in the lower insulator tip
generally occurs during several engine operating
conditions (high speeds or heavy loading) and may be
caused by over-advanced timing or low grade fuels.
Heat shock refers to a rapid increase in the tip
temperature that causes the insulator material to
crack.
Spark plugs with less than the recommended amount of
service can sometimes be cleaned and re-gapped , then
returned to service. However, if there is any doubt about
the serviceability of a spark plug, replace it. Spark plugs
with cracked or broken insulators should always be
replaced.
A/C Clutch Diagnosis
A/C Clutch Circuit Operation
A 12-volt signal is supplied to the A/C request input of the
PCM when the A/C is selected through the A/C control
switch.
The A/C compressor clutch relay is controlled through the
PCM. This allows the PCM to modify the idle air control
position prior to the A/C clutch engagement for better idle
quality. If the engine operating conditions are within their
specified calibrated acceptable ranges, the PCM will
enable the A/C compressor relay. This is done by
providing a ground path for the A/C relay coil within the
PCM. When the A/C compressor relay is enabled,
battery voltage is supplied to the compressor clutch coil.
The PCM will enable the A/C compressor clutch
whenever the engine is running and the A/C has been
requested. The PCM will not enable the A/C compressor
clutch if any of the following conditions are met:
The throttle is greater than 90%.
The engine speed is greater than 6315 RPM.
The ECT is greater than 119C (246F).
The IAT is less than 5C (41F).
The throttle is more than 80% open.
A/C Clutch Circuit Purpose
The A/C compressor operation is controlled by the
powertrain control module (PCM) for the following
reasons:
It improvises idle quality during compressor clutch
engagement.
It improvises wide open throttle (WOT) performance.
It provides A/C compressor protection from operation
with incorrect refrigerant pressures.
The A/C electrical system consists of the following
components:
The A/C control head.
The A/C refrigerant pressure switches.
The A/C compressor clutch.
The A/C compressor clutch relay.
The PCM.
A/C Request Signal
This signal tells the PCM when the A/C mode is selected
at the A/C control head. The PCM uses this to adjust the
idle speed before turning on the A/C clutch. The A/C
compressor will be inoperative if this signal is not
available to the PCM.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for A/C electrical system.
General Description (Exhaust Gas
Recirculation (EGR) System)
EGR Purpose
The exhaust gas recirculation (EGR) system is use to
reduce emission levels of oxides of nitrogen (NOx). NOx
emission levels are caused by a high combustion
temperature. The EGR system lowers the NOx emission
levels by decreasing the combustion temperature.
057RW002
Linear EGR Valve
The main element of the system is the linear EGR valve.
The EGR valve feeds small amounts of exhaust gas back
into the combustion chamber. The fuel/air mixture will be
diluted and combustion temperatures reduced.
Linear EGR Control
The PCM monitors the EGR actual positron and adjusts
the pintle position accordingly. The 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.
Linear EGR Valve Operation and Results
of Incorrect Operation
The linear EGR valve is designed to accurately supply
EGR to the engine independent of intake manifold
vacuum. The valve controls EGR flow from the exhaust

6E–350
ENGINE DRIVEABILITY AND EMISSIONS
to the intake manifold through an orifice with a PCM
controlled pintle. During operation, the PCM controls
pintle position by monitoring the pintle position feedback
signal. The feedback signal can be monitored with Tech 2
as “Actual EGR Pos.” “Actual EGR Pos.” should always
be near the commanded EGR position (”Desired EGR
Pos.”). If a problem with the EGR system will not allow the
PCM to control the pintle position properly, DTC P1406
will set. The PCM also tests for EGR flow. If incorrect flow
is detected, DTC P0401 will set. If DTCs P0401 and/or
P1406 are set, refer to the DTC charts.
The linear EGR valve is usually activated under the
following conditions:
Warm engine operation.
Above-idle speed.
Too much EGR flow at idle, cruise or cold operation may
cause any of the following conditions to occur:
Engine stalls after a cold start.
Engine stalls at idle after deceleration.
Vehicle surges during cruise.
Rough idle.
Too little or no EGR flow may allow combustion
temperatures to get too high. This could cause:
Spark knock (detonation).
Engine overheating.
Emission test failure.
DTC P0401 (EGR flow test).
Poor fuel economy.
0017
EGR Pintle Position Sensor
The PCM monitors the EGR valve pintle position input to
endure that the valve responds properly to commands
from the PCM and to detect a fault if the pintle position
sensor and control circuits are open or shorted. If the
PCM detects a pintle position signal voltage outside the
normal range of the pintle position sensor, or a signal
voltage that is not within a tolerance considered
acceptable for proper EGR system operation, the PCM
will set DTC P1406.
General Description (Positive
Crankcase Ventilation (PCV) System)
Crankcase Ventilation System Purpose
The crankcase ventilation system is use to consume
crankcase vapors in the combustion process instead of
venting them to the atmosphere. Fresh air from the
throttle body is supplied to the crankcase and mixed with
blow-by gases. This mixture is then passed through the
positive crankcase ventilation (PCV) valve into the
common chamber.
Crankcase Ventilation System Operation
The primary control is through the positive crankcase
v e n t i l a t i o n ( P C V ) v a l v e . T h e PCV valve meters the flow at
a rate that depends on the intake vacuum. The PCV valve
restricts the flow when the inlet vacuum is highest. In
addition, the PCV valve can seal the common chamber
off in case of sudden high pressure in the crankcase.
028RV002
While the engine is running, exhaust fuses and small
amounts of the fuel/air mixture escape past the piston

6E–351 ENGINE DRIVEABILITY AND EMISSIONS
rings and enter the crankcase. These gases are mixed
with clean air entering through a tube from the air intake
duct.
028RW002
During normal, part-throttle operation, the system is
designed to allow crankcase gases to flow through the
PCV valve into the throttle body to be consumed by
normal combustion.
A plugged valve or PCV hose may cause the following
conditions:
Rough idle.
Stalling of slow idle speed.
Oil leaks.
Sludge in the engine.
A leaking PCV hose would cause:
Rough idle.
Stalling.
High idle speed.

6G–4
ENGINE LUBRICATION
11. Remove drive gear.
12. Remove oil seal.
13. Remove O-ring.
Inspection and Repair
CAUTION: Make necessary correction or parts
replacement if wear, damage or any other abnormal
conditions are found during inspection.
Relief Valve (8)
Check to see that the relief valve slides freely.
The oil pump must be replaced if the relief valve does
not slide freely.
Replace the spring and/or the oil pump assembly (5) if
the spring is damaged or badly worn.
051RS002
Body (14) and Gears (10, 11)
The pump assembly must be replaced if one or more of
the conditions below is discovered during inspection.
Badly worn or damaged driven gear (10).
Badly worn drive gear (11) driving face.
Badly scratched or scored body sliding face (14) or
driven gear (10).
Badly worn or damaged gear teeth.
Measure the clearance between the body and the driven
gear with a feeler gauge.
Standard : 0.10 mm–0.18 mm
(0.0039 in.–0.0070 in)
Limit : 0.20mm (0.0079 in)
051RS004
Measure the clearance between the drive gear and
driven gear with a feeler gauge.
Standard : 0.11 mm–0.24 mm
(0.0043 in–0.0094 in)
Limit : 0.35mm (0.0138 in)
051RS003
Measure the side clearance with a precision straight
edge and a feeler gauge.
Clearance
Standard : 0.03 mm–0.09 mm
(0.0011 in–0.0035 in)
Limit : 0.15mm (0.0059 in)

ENGINE MECHANICAL 6A – 81
DISASSEMBLY
1. Cylinder Head Assembly
1) Refer to “Cylinder head” in this manual.
2. Crank Case Assembly
1) Refer to “Crank Case” in this manual.
3. Connecting Rod Bearing Cap
4. Piston and Connecting Rod
1) Remove carbon deposits from the upper portion
of the cylinder wall with a scraper before
removing the piston and connecting rod.
5. Piston Ring
Remove the piston rings with a piston ring
expander.
Arrange the removed piston rings in the cylinder
number order.
6. Piston Pin Snap Ring
1) Use a pair of pliers to remove the piston pin
snap rings.7. Piston Pin
1) Remove piston pin from piston assembly.
NOTE: Keep the parts removed from each cylinder
separate. All parts must be reinstalled in their original
positions.
8. Piston
9. Connecting Rod
INSPECTION AND REPAIR
PISTON AND PISTON RING
Pistons
Carefully clean away all the carbon adhering to the
piston head and the piston ring grooves.
NOTE: Never use a wire brush to clean the pistons.
Damage will result. Visually check each piston for
cracking, scoring, and other signs of excessive wear. If
any of the above conditions are present, the piston
must be replaced.
Piston Diameter
1. Measure the piston outside diameter with
micrometer at the piston grading position.
Piston Grading Position: 69.75 mm (2.7461 in)
from piston head
Piston Outside Diameter mm(in)
Grade Mark Outside Diameter
A 95.320 – 95.329 (3.7527 – 3.7531)
B 95.330 – 95.339 (3.7531 – 3.7535)
C 95.340 – 95.349 (3.7535 – 3.7539)
015RW082
015RW077
015LV014

ENGINE COOLING 6B – 5
ENGINE COOLANT CHANGE
PROCEDURE
1. To change engine coolant, make sure that the
engine is cool.
WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor or
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure once the coolant has
become cooler.
2. Open radiator cap and drain the cooling system by
loosening the drain valve on the radiator and on the
cylinder body.
NOTE: For best results it is suggested that the engine
cooling system be flushed at least once a year. It is
advisable to flush the interior of the cooling system
including the radiator before using anti-freeze
(ethylene-glycol based).
Replace damaged rubber hoses as the engine anti-
freeze coolant is liable to leak out even minor cracks.
Isuzu recommends using Isuzu genuine anti-freeze
(ethylene-glycol based) or equivalent, for the cooling
system and not add any inhibitors or additives.
CAUTION:
A failure to correctly fill the engine cooling system
in changing or topping off coolant may sometimes
cause the coolant to overflow from the filler neck
even before the engine and radiator are completely
full.
If the engine runs under this condition, shortage of
coolant may possibly result in engine overheating.
To avoid such trouble, the following precautions
should be taken in filling the system.
3. To refill engine coolant, pour coolant up to filler neck
using a filling hose which is smaller in outside
diameter than the filler neck. Otherwise air between
the filler neck and the filling hose will block entry,
preventing the system from completely filling up.
4. Keep a filling rate of 9 liter/min. or less. Filling over
this maximum rate may force air inside the engine
and radiator.
And also, the coolant overflow will increase, making
it difficult to determine whether or not the system is
completely full.
5. After filling the system full, pull out the filling hose
and check to see if air trapped in the system is
dislodged and the coolant level goes down. Should
the coolant level go down, repeat topping-off until
there is no more drop in the coolant level.
6. Directly after filling the radiator, fill the reservoir to
the maximum level.
7. Install and tighten radiator cap and start the engine.
After idling for 2 to 3 minutes, stop the engine and
reopen radiator cap. If the water level is lower,
replenish.WARNING:
When the coolant is heated to a high temperature,
be sure not to loosen or remove the radiator cap.
Otherwise you might get scalded by hot vapor or
boiling water. To open the radiator cap, put a piece
of thick cloth on the cap and loosen the cap slowly
to reduce the pressure once the coolant has
become cooler.
8. After tightening radiator cap, warm up the engine at
about 2,000 rpm.
Set heater adjustment to the highest temperature
position, and let the coolant circulate also into
heater water system.
9. Check to see the thermostat has opened by the
needle position of a water thermometer, conduct a
5-minute idle again and stop the engine.
10. When the engine has been cooled, check filler neck
for water level and replenish if required. Should
extreme shortage of coolant be found, check the
coolant system and reservoir tank hose for leakage.
11. Fill the coolant into the reservoir tank up to “MAX”
line.

ENGINE FUEL 6C – 21
FUEL GAUGE UNIT
1
2
6
7
4
5
3
140RX023
REMOVAL
1 Disconnect battery ground cable.
2 Loosen fuel filler cap.
3 Drain fuel.
After drain the fuel tighten the drain plug with
specified torque.
Torque : 20 Nꞏm (2.0 kgꞏm/14 lb ft)
4. Disconnect harness connector from fuel gauge unit.
5. Fuel Gauge Unit
1) Remove the fixing screws, then the fuel gauge
unit.
INSTALLATION
1. Fuel Gauge Unit
2 Connect the harness connector to the fuel gage
unit.
3 Fill the tank with fuel and tighten fuel filler cap.
4 Connect battery ground cable.
FUEL FILLER CAP
The fuel filler cap contains a vacuum valve. If a
negative pressure develops in the fuel tank, the
external valve of the fuel filler cap opens to allow the
fresh air to flow into the fuel tank through the vacuum
valve.
INSPECTION
Check the seal ring in the filler cap for presence of any
abnormality and for seal condition.
Replace the filler cap, if abnormal.Legend
(1) Vacuum Valve
(2) Pressure Valve Legend
(1) Fuel Tank Assembly
(2) Fuel Gauge Unit
(3) Under Cover(4) Filler Hose
(5) Filler Cap
(6) Breather Hose
(7) Control Valve (Except EC)
1
2
060RW098

ENGINE ELECTRICAL 6D – 11
5) Polish the commutator surface with sand paper
#500 to #600 if it is rough.
6) Measure the depth of insulator in commutator.
Repair, if it is below the limit.
Standard: 0.5 – 0.8 mm (0.02 – 0.03 in)
Limit: 0.2 mm (0.008 in)
Legend
(1) Steel Saw
(2) Chamfer
(3) Correct Condition
(4) Depth of Insulator
(5) Incorrect Condition
(6) Insulator
(7) Commutator SegmentBrush
1) Measure the length of brush.
Replace with a new one, if it is below the limit.
Standard: 18.0 mm (0.71 in)
Limit: 11.0 mm (0.43 in)
Brush holder
1) Check for continuity between brush holder (+) and
base (–). Replace, if there is continuity (i.e.,
insulation is broken).
065RW105
1
6
53 42 7
065RW102
065RW103
065RW104