maintenance ISUZU TROOPER 1995 Owner's Manual

6-16 ENGINE DIAGNOSIS
ENGINE OIL PRESSURE CHECK
1. Check for dirt, gasoline or water in the engine
oil.
a. Change the oil if dirt, gasoline, or water
are present.
b. Check the viscosity of the oil.
c. Change the oil if the viscosity is outside
the specified standard.
d. Refer to the "Maintenance and Lubrication"
section of this manual.
2. Check the engine oil level.
The level should fall somewhere between the
"ADD" and the "FULL" marks on the oil level
dipstick.
If the oil level does not reach the "ADD" mark
on the
oil level dipstick, engine oil must be
added.
3. Remove the oil pressure unit.
4. Install an oil pressure gage.
5. Start the engine and allow the engine to reach
normal operating temperature (About 80°C).
6. Measure the oil pressure.
Oil pressure should be:
7. Stop the engine.
392-550 kPa (56.9-80.4 psi)
at
3000 rpm.
8. Remove the oil pressure gage.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.
m ... cw
•

6C - 4 ENGINE FUEL
I1!]1NSPECTION
After installation, start engine and check for fuel leak­
age.
IN-TANK FUEL FILTER
The filter is located on the lower end of fuel pickup
tube in the fuel tank. It prevents dirt from entering the
fuel pipe and also stops water unless the filter is
completely submerged in the water. It is a self-cleaning
type, not requiring scheduled maintenance. Excess
water and sediment in the tank restricts fuel supply to
the engine, resulting in engine stop. In such a case, the
tank
must be cleaned throughly.
FUEL PUMP FLOW TEST
If reduction of fuel supply is suspected, perform
checking as follows.
Preparation:
• Make sure that there is fuel in the tank.
• With the engine running, check the fuel feed
pipe and hose
from fuel tank to injector for
evidence of leakage.
Retighten, if pipe or hose connection is loose.
Also,
check pipes and hoses for squashing or
clogging.
1. Receive the hose from fuel feed pipe with a clean
container, and check for fuel pump flow rate.
2. Connect the pump relay terminals with a jumper
wire as shown and start the fuel pump to measure
delivery. (Fig. 6C-4)
W CAUTION:
Never generate sparks when connecting a jumper
wire.
Fig. 6C-4
Delivery Delivery
15 seconds 0.38
liters minimum
If the measure value is out of standard, conduct the
pressure test.
Pressure test
For the pressure test to the fuel system, see Section 6E
"Fuel Control System".
II

6E2-2 DRIVEABILITY AND EMISSIONS
DRIVEABILITV AND EMISSIONS GENERAL INFORMATION
CONTENTS
General Information
Driveability ....................... .
Emissions
........................ .
Maintenance
Schedule .............. .
Introduction ...................... .
Electronic Engine
Control .......... .
What This Section Contains ........ .
Blocking Drive Wheels
Visual/Physical
Underhood Inspection
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
6E2-3
Basic
Knowledge required . . . . . . . . . . . . 6E2-4
Basic Electric Circuits . . . . . . . . . . . . . .
6E2-4
Use
of Circuit Testing Tools . . . . . . . . . 6E2-4
Use
of Digital Volt-Ohm Meter (DVOM). 6E2-4
Diagnostic
Information . . . . . . . . . . . . . . . 6E2-4
"Check Engine" Malfunction Indicator
Lamp (MIL) . . . . . . . . . . . . . . . . . . . . 6E2-4
Intermittent "Check Engine"
Malfunction Indicator Lamp (MIL) . . 6E2-4
Reading Diagnostic
Trouble Codes . . . 6E2-5
Clearing
Trouble Codes . . . . . . . . . . . . 6E2-5
Diagnostic Test
Mode .............. 6E2-5
Engine Control
Module Learning
Ability . . . . . . . . . . . . . . . . . . . . . . . . 6E2-6
Field
Service Mode . . . . . . . . . . . . . . . . 6E2-6
Standard Nomenclature
for Certain
Electrical/Electronic
Components
and Systems . . . . . . . . . . . . . . . . . . . 6E2-6
Abbreviations and Glossary of Terms ..... 6E2-11
Driveability and Emissions
Section Summary ................... 6E2-12
Section .,. A"
Diagnostic Procedure Summary ...... 6E2-13
Data Link Connector
"SCAN Tools" ..... 6E2-14
Data
List (FO) ...................... 6E2-14
"SCAN Tool" Limitations and Use ...... 6E2-14
Intermittent Conditions ............ 6E2-14
"SCAN Tool" Positions ............... 6E2-14
Injector Pulse Width ............... 6E2-14
Closed Loop/Open Loop . . . . . . . . . . . .
6E2-14
Trouble Codes ................... 6E2-14
Throttle Position (TP) Sensor . . . . . . . . 6E2-14
Throttle Angle . . . . . . . . . . . . . . . . . . . 6E2-15 Heated
Oxygen
Sensor (H02S)
Vehicle Speed Sensor (VSS) ....... .
Programmable Read Only Memory ID .
Revolution
Per Minute (RPM) ...... .
Mile Per Hour (MPH) ............. .
Engine
Coolant Temperature (ECT) .. .
Intake Air Temperature (IAT)
Sensor
...................... .
Manifold Absolute Pressure (MAP) .. .
Barometric Pressure (BARO) ....... .
Exhaust Gas Recirculation
(EGR)
(ON/OFF) .................... .
Short Term (S.T.) Fuel Trim and
Long Term
(LT.) Fuel Trim ...... .
Long Term
(LT.) Fuel Trim ........ .
Idle Air Control (lAC) Counts ....... .
Desired Revolution
Per Minute ..... .
Air Conditioning (A/C) Request ..... .
Air Conditioning (A/C) Clutch ...... .
Power Steering Pressure (PSP)
Switch ...................... .
Battery Positive Voltage .......... .
Spark Advance .................. .
Start Up Engine Coolant .......... .
Engine
Speed (RPM) ............. .
Fuel Trim Enable ................ .
Air/Fuel Ratio .................. .
Induction Air Control ............. .
Section B -Driveability Symptoms ... .
Section C -Component Systems .... .
Engine
Control Module (ECM)
and
Sensors .................. .
Fuel Control System ............. .
Electric
Fuel Pump (in-tank) ....... .
Evaporative Emission
(EVAP)
Control System ................ .
Ignition Control (IC) .............. .
Exhaust Gas Recirculator
(EGR) .... .
Air Conditioning (A/C) Clutch Control .
Positive Crankcase Ventilation (PCV) .
Tools Needed
to Service the System .... .
General Specifications
............... .
Vacuum Hose Routing Diagram
........ .
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-15
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-16
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-17
6E2-18
6E2-21
6E2-22
~
... ...
•

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DRIVEABILITV AND EMISSIONS 6E2-3
ALL NEW ISUZU VEHICLES ARE CERTIFIED BY THE UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY AS CONFORMING TO THE REQUIREMENTS OF THE REGULATIONS FOR THE CONTROL OF AIR
POLLUTION FROM NEW MOTOR VEHICLES. THIS CERTIFICATION IS CONTINGENT ON CERTAIN
ADJUSTMENTS BEING SET TO FACTORY STANDARDS. IN MOST CASES, THESE ADJUSTMENT POINTS
EITHER HAVE BEEN PERMANENTLY SEALED AND/OR MADE INACCESSIBLE TO PREVENT INDISCRIMINATE
OR ROUTINE ADJUSTMENT IN THE FIELD. FOR THIS REASON, THE FACTORY PROCEDURE FOR
TEMPORARILY REMOVING PLUGS, CAPS, ETC., FOR PURPOSES OF SERVICING THE PRODUCT, MUST BE
STRICTLY FOLLOWED AND, WHEREVER PRACTICABLE, RETURNED TO THE ORIGINAL INTENT OF THE
DESIGN.
GENERAL INFORMATION
DRIVEABILITY
The driveability diagnosis procedures apply to various
systems in current
ISUZU vehicles. The procedures
assume
that the vehicle is worked on properly at one
time and the
problem is due to time, wear, dirt or other
causes.
Start with the introduction that follows. This
will describe a systematic diagnostic procedure.
Any system disconnected during diagnosis should be
reconnected. This
includes wires, hoses, linkage, etc.
EMISSIONS
The exhaust emission control systems used on
ISUZU engines perform a specific function to lower
exhaust emissions while maintaining good fuel
economy and driveability.
MAINTENANCE SCHEDULE
Refer to the Maintenance Schedule in Section "OB"
General Information for the maintenance service that
should be performed to retain emission control
performance.
INTRODUCTION
ELECTRONIC ENGINE CONTROL
All engines have an Engine Control Module (ECM)
to control the fuel system. The ECM varies the air/
fuel ratio by controlling the fuel flow through the
injectors.
In addition, the ECM controls the ignition timing,
fuel pump, and various other systems.
It is important to review the component sections
and
wiring diagrams in this Section for specific
components
controlled by the ECM and what
systems are non-ECM controlled.
WHAT THIS SECTION CONTAINS
Each ISUZU engine has system controls to reduce
exhaust emissions
while maintaining good
driveability and fuel economy. •
This Section explains:
•
How to use the Driveability and Emission
Section
"6E2" engines.
• A brief description of systems used to
control fuel and emissions.
• Abbreviations that are used in Driveability
and Emissions.
• Special tools used to diagnosis and repair a
system.
Before checking the
system, adhere to the
following information:
BLOCKING DRIVE WHEELS
The vehicle drive wheels should always be
blocked, and parking brake firmly set, while
checking the system.
VISUAL/PHYSICAL UNDERHOOD
INSPECTION
A careful visual and physical underhood
inspection must
be performed as part of any
diagnostic procedure
or in finding the cause of an
emissions test failure. This can often lead to fixing
a
problem without further steps. Inspect all
vacuum hoses for correct routing, pinches, cuts,
or disconnections. Be sure to inspect hoses that
are
difficult to see beneath the throttle body and
common chamber.
Inspect all the wires in the
engine
compartment for correct and good
connections, burned or chaffed spots, pinched
wires, or contact with sharp edges or hot exhaust
manifolds. This visual/physical inspection is very
important. It must be done carefully and
thoroughly.

DRIVEABILITY AND EMISSIONS 6E2-21
Engine control module connector terminal remover Intake manifold diagnostic plate
Used to remove terminal from Micro-Pack connectors.
Engine
control module connector terminal remover: J-
33095
Used to fuel rail pressure test and fuel injector balance
test.
Fig. 6E2-14
Intake manifold diagnostic plate: J-39185
GROUND BOLT
€3 EXHAUST GAS RECIRCULATION (EGR) EXHAUST MANIFOLD PLATE
INTAKE BOLT SPACER
Fig. 6E2-14
GENERAL SPECIFICATIONS
"S''
Many of the specifications used in this section are located on the Vehicle Emission Control Information Label
under the hood.
Listed on the chart
below are locations of specifications used in this Section.
Specification Location of information
Engine Timing
Not adjustable, engine control module controls timing.
Idle Speed Not adjustable, engine control module controls idle.
Spark Plug Type See "Identification" in Section OA.
Spark Plug Gap Vehicle Emission Control Information Label.
Engine Diagnostic Trouble 8th digit of VIN number. See "Maintenance Service Data" in Section 08.
Code
Part Numbers of Major AIPDN (American lsuzu Parts Dept. Network)
Components
Replacement of Vehicle ISUZU Parts Catalog.
Emission Control
Information Label
AIPDN
(American lsuzu Parts Dept. Network)

6F-2 ENGINE EXHAUST (V6 3.2L)
When inspecting or replacing exhaust system
components, make sure there is adequate
clearance
from all points on the underbody to prevent over­
heating the
floor pan and possible damage to the
passenger
compartment insulation and trim materials.
Check complete exhaust system and nearby body
areas and rear compartment lid for broken, damaged,
missing
or mispositioned parts, open seams, holes,
loose
connections or other deterioration which could
permit exhaust fumes to seep into the rear
compartment or passenger compartment. Dust or
water in the rear compartment may be an indication of
a problem in one of these areas. Any faulty areas
should be corrected immediately.
HANGERS
Various types of hangers are used to support exhaust
system(s). These
include conventional rubber straps,
rubber rings, and rubber
blocks.
The installation of exhaust system supports is very
important,
as improperly installed supports can cause
annoying vibrations
which can be difficult to diagnose.
THREE WAY CATAL VTIC CONVERTER
The three way catalytic converter is an emission
control device added to the exhaust system to reduce
pollutants from the exhaust gas stream.
W CAUTION:
VI • The catalytic converter requires the use of
unleaded fuel only.
Periodic
maintenance of the exhaust system is not
required. If the vehicle is raised for other service, it is
advisable to check the condition of the complete
exhaust system.
A
dual bed monolith catalytic converter is used in
combination
with three way catalytic converter.
Catalytic Types:
Three
way (Reduction/Oxidation) catalyst
The catalyst coating on the three way (reduction)
converter contains
platinum and rhodium which
lowers the levels of oxide of nitrogen (NOx) as well as
hydrocarbons (HC) and carbon monoxide (Co).
GASKET
The gasket must be replaced whenever a new exhaust
pipe,
muffler or catalytic converter is installed.

7 A-20 AUTOMATIC TRANSMISSION (4L30-E)
CHECKING TRANSMISSION FLUID
LEVEL AND CONDITION
Checking fluid level and condition (color and odor)
at
regular intervals will provide early diagnosis
information about the transmission. This inform­
ation may be used to correct a condition that, if not
detected early, could result in major transmission
repairs.
IMPORTANT: When new, automatic transmission
fluid is red in color. As the vehicle is driven, the
transmission
fluid will begin to look darker in color.
The
color may eventually appear light brown.
A DARK
brown color with burnt odor may indicate
excessive
fluid deterioration and signal a need for
fluid change.
FLUID LEVEL
When adding
or changing fluid, use only DEXRON
®-Ill.
Refer to the Maintenance and Lubrication (Section 0
of this manual) for maintenance information and
servicing
interval.
\f CAUTION: DO NOT OVERFILL
Overfilling will cause foaming, loss ~f fluid,
abnormal shifting and possible damage to
the transmission.
1. Start engine and drive vehicle until normal AfT
oil operating temperature is reached:
NOTE: The automatic transmission fluid level
must be checked with the vehicle at normal
A/T oil operating temperature: 75 TO 85°C
(167 TO 185°F) MEASURED WITH TECH1 SCAN
TOOL.
Temperature will greatly affect transmission
fluid level.
If the vehicle is not at normal AfT oil operating
temperature and the proper checking
procedures are
not followed, the result could
be a false reading of the fluid level indicator
and
an incorrect adjustment of the fluid level.
2. Park vehicle on level ground.
3. Move gear selector to "Park".
4. Apply parking brake and block wheels.
5. Allow vehicle to idle for 3 minutes with all
accessories turned off.
6. Check fluid level with engine running at idle:
Fluid should
be in "HOT" area on AfT dipstick
(Fig. 7A-6).
Check also color and condition (Refer to next
page.)
Hot
Cold ---IIU 0
0
Min
Dipstick
Fig. 7A-6
\f CAUTION:
DO NOT CHECK FLUID LEVEL UNDER THESE
CONDITIONS: •
At high ambient temperature above 30°C
(86°F).
Immediately after driving at sustained highway
speeds.
• In heavy city traffic during hot weather.
If vehicle is towing a trailer.
If the vehicle has been operated under these
conditions,
shut the engine off and allow the
vehicle to "cool" for thirty (30) minutes. After the
cool-down period, restart the vehicle and continue
from step 2 above.
'~I
......

AUTOMATIC TRANSMISSION (4L30-E) 7A-21
FLUID CONDITION
FLUID CONDITION
NORMAL* CONTAMINATED
COLOR
RED BROWN NON-TRANSPARENT BROWN OR LIGHT BROWN
/PINK
DRAIN NO
YES YES YES
REQUIRED?
CO NT AMI- NONE Very small amount Contamination by Large pieces of
NATION of foreign material coolant or other metal or other
in bottom of pan
source foreign material in
bottom of pan
1. LOW LEVEL:
A. Add fluid to -
Remove both pans -Repair/replace
obtain
proper radiator cooler
level
& check -Change filter -Transmission -Transmission
CORRECT for external overhaul required overhaul required
LEVEL leaks. See -Flush cooler -Check for:
& chart 16..811 • Damaged plates -Flush cooler and
CONDITION ~· -Add new fluid and seals cooler
lines
B. Correct cause • Contaminated -Add new fluid
of leak. -Check level solenoids
2. HIGH LEVEL: -Flush cooler -Check level
-Remove excess -Add new fluid
fluid -Check level
* Fluid should be changed according to maintenance schedule.