1998 OPEL FRONTERA engine

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.

6E–352
ENGINE DRIVEABILITY AND EMISSIONS
Special Tools
901RW180
Legend
(1) PCMCIA Card
(2) RS232 Loop Back Connector(3) SAE 16/19 Adapter
(4) DLC Cable
(5) TECH–2

6E–353 ENGINE DRIVEABILITY AND EMISSIONS
ILLUSTRATIONTOOL NO.
TOOL NAME
5-8840-0285-0
(J 39200)
High Impedance
Multimeter (Digital
Vo l t m e t e r – D V M )
(1) PCMCIA Card
(2) RS232 Loop Back
Connector
(3) SAE 16/19 Adapter
(4) DLC Cable
(5) TECH–2
5-8840-0607-0
(J 34142-B)
Unpowered Test Light
5-8840-0385-0
(J 35616-A/BT-8637)
Connector Test
Adapter Kit
5-8840-0383-0
(J 26792/BT-7220-1)
Spark Tester
5-8840-0279-0
(J 23738-A)
Vacuum Pump with
Gauge common tool
ILLUSTRATIONTOOL NO.
TOOL NAME
BT-8515
Exhaust Back Pressure
Tester or common tool
5-8840-2640-0
(J 39194-B)
Heated Oxygen Sensor
Wrench
5-8840-0632-0
(J 35689-A)
Terminal Remover
5-8840-0388-0
(J 28742-A)
Weather Pack II
Terminal Remover
5-8840-2635-0
(J 39021-90)
Injector Switch Box
5-8840-2636-0
(J 39021-65)
Injector Test Light

6E–354
ENGINE DRIVEABILITY AND EMISSIONS
ILLUSTRATIONTOOL NO.
TOOL NAME
5-8840-2607-0
(J 41413)
EVAP Pressure/Purge
Diagnostic Station
5-8840-2608-0
(J 41416)
Ultrasonic Leak Detector
1. 5-8840-2607-0 (J-41413)EVAP Pressure/Purge
Diagnostic Station is a multipurpose tool which is
used to perform several diagnostic procedures for
enhanced emission testing. The station will
accommodate a nitrogen gas filled cylinder which is
used to pressurize the vehicle EVAP system for a
leakdown test and leak location test when a vehicle is
repaired for leakage in the enhanced evaporative
emission control system. It also has two additional
gauges (inches of mercury and inches of water) which
are used to measure both source vacuum and EVAP
canister purge vacuum to verify correct operation and
vapor flow within the canister purge circuit.
2. 5-8840-2608-0 (J-41416) Ultrasonic Leak Detector is
a microprocessor-based device used to detect leaks
in the enhanced evaporative emission control
system. The evaporative system is pressurized to 30
inches of water using the 5-8840-2607-0 (J-41413)
EVAP Pressure/Purge Diagnostic System. Small
leaks in the EVAP system will emit sound at a high
frequency undetectable by a human ear but
detectable with the 5-8840-2608-0 (J-41416). The
technician traces along the evaporative system and
can pinpoint leaks due to corroded lines, cracked
hoses, or a damaged EVAP component. The
detector includes a high quality set of headphones to
block out surrounding shop noise and the LED
sensitivity meter allows a visual reference for locating
leaks in conjunction with the audio output heard
through the headphones. Powered by (1) nine volt
battery.

6F–1 ENGINE EXHAUST
ENGINE
ENGINE EXHAUST
CONTENTS
Service Precaution 6F–1. . . . . . . . . . . . . . . . . . . . . .
General Description 6F–2. . . . . . . . . . . . . . . . . . . . .
Front Exhaust Pipe 6F–4. . . . . . . . . . . . . . . . . . . . . .
Front Exhaust Pipe and Associated Parts 6F–4.
Removal 6F–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F–4. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Three Way Catalytic Converter 6F–5. . . . . . . . . . . .
Removal 6F–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . Exhaust Silencer 6F–6. . . . . . . . . . . . . . . . . . . . . . . .
Exhaust Silencer and Associated Parts 6F–6. . .
Removal 6F–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F–6. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Exhaust pipe 6F–7. . . . . . . . . . . . . . . . . . . . . . .
Rear Exhaust pipe and Associated Parts 6F–7.
Removal 6F–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Installation 6F–7. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Main Data and Specifications 6F–8. . . . . . . . . . . . .
Service Precaution
WARNING: IF SO EQUIPPED WITH A
SUPPLEMENTAL RESTRAINT SYSTEM (SRS),
REFER TO THE SRS COMPONENT AND WIRING
LOCATION VIEW IN ORDER TO DETERMINE
WHETHER YOU ARE PERFORMING SERVICE ON OR
NEAR THE SRS COMPONENTS OR THE SRS
WIRING. WHEN YOU ARE PERFORMING SERVICE
ON OR NEAR THE SRS COMPONENTS OR THE SRS
WIRING, REFER TO THE SRS SERVICE
INFORMATION. FAILURE TO FOLLOW WARNINGS
COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR
OTHERWISE UNNEEDED SRS SYSTEM REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, or other
corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener. When
you install fasteners, use the correct tightening
sequence and specifications. Following these
instructions can help you avoid damage to parts and
systems.

6F–2ENGINE EXHAUST
General Description
General export with three way catalytic converter
model
150RW060
General export with out three way catalytic
converter model
150RW059