air filter ISUZU TROOPER 1995 User Guide

6-8 ENGINE DIAGNOSIS
ENGINE LACKS POWER
Condition
Possible cause Correction
Trouble in fuel system Fuel Pressure Control Valve not Replace
working normally
Fuel
injector clogged Clean or replace
Fuel
pipe clogged Clean
Fuel filter clogged
or fouled Replace
Fuel
pump drive circuit not working Correct or replace
normally
Fuel tank not sufficiently breathing due Clean or replace
to clogged Evaporative Emission
Control System circuit
Water in
fuel system Clean
Inferior quality fuel
in fuel system Use fuel of specified octane
rating
Engine
Control Module supplied poor Correct circuit
voltage
Throttle
Position Sensor cable Correct or replace
disconnected or broken
Throttle Position Sensor defective Replace
Manifold Absolute
Pressure Sensor not Replace
working normally
Intake Air Temperature Sensor not Replace
working normally
Engine Coolant Temperature Sensor Correct or replace
circuit open or shorted
Engine
Coolant Temperature Sensor Replace
defective
Engine
Control Module defective Replace
Trouble
in intake or exhaust Air Cleaner Filter clogged Replace filter element
system Trouble in Induction air control valve Correct or replace
system (DOHC)
Air duct kinked or flattened Correct or replace
Ignition failure
Refer to Hard Start
Troubleshooting Guide
Heat range
of spark plug inadequate Install spark plugs of adequate
heat range
Electronic Ignition System with module Replace
•

6-14 ENGINE DIAGNOSIS
1;:-
FUEL CONSUMPTION EXCESSIVE
Condition
Possible cause Correction
Trouble in fuel system
Mixture too rich or too lean due to Refer to "Abnormal Combus-
trouble in fuel injection system tion"
Fuel cut function does not act Refer to "Abnormal Combus-
tion"
Trouble in ignition system
Misfiring or abnormal combustion due Refer to Hard Start or
to trouble in ignition system Abnormal Combustion
Troubleshooting Guide
Others Engine idle speed too high Reset Idle Air Control Valve
Returning
of accelerator control Correct
sluggish
Fuel system leakage
Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear incorrect Caution operator of incorrect
gear selection
Excessive Exhaust
Gas Recirculation Refer to Abnormal
flow due to trouble in Exhaust Gas Combustion
Recirculation system
OIL PROBLEMS
Condition
Possible cause Correction
Oil pressure too low Wrong oil in use Replace with correct
engine
oil
Relief valve sticking Replace
Oil pump not operating
properly Correct or replace
Oil pump strainer clogged Clean or replace strainer
Oil pump worn Replace
Oil pressure gauge defective Correct or replace
Crankshaft bearing or connecting-rod Replace
bearing
worn
Oil contamination Wrong oil in use Replace with new engine
oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace
gasket
Burned gases leaking Replace piston and piston rings
or rebore cylinders
Oil not reaching valve system Oil passage in cylinder head or cylinder Clean or correct
body clogged
•

OIL COOLER
1
ENGINE (V6 3.2L DOHC AND SOHC) 6A 1-55
Removal steps
1.
Oil filter 2. Engine coolant hoses
3. Oil cooler
Installation
steps To install, follow the removal steps in the reverse order.
3
Fig. 6A1-67
1••1 REMOVAL
Preparation: Battery ground cable
1. Oil filter
li5\1 • Remove using the filter wrench.
~ Filter wrench: J-36390
2. Engine
coolant hoses
• Disconnect two coolant hoses from oil cooler.
3. Oil cooler
• Remove center bolt, then the oil cooler.
U!)INSPECTION AND REPAIR
Check oil cooler and center bolt for cracks, flaws and
other damage, and
replace as necessary.
1••1 INSTALLATION
3. Oil cooler
m • Clean sealing surfaces of oil cooler and cylinder
L41 body.
• Install center bolt and oil cooler on the oil cooler
adapter, and tighten center bolt to the specified
torque.
~~~ Torque N·m (lb·ft) 26 (20)
2. Engine coolant hoses
1.
Oil filter

ENGINE FUEL 6C-1
SECTION 6C
ENGINE FUEL
CONTENTS
General Description ....................... .
Fuel Metering ............................ .
On-Vehicle Service ........................ .
Fuel Filter ................................. .
In Tank Fuel Filter ............................. .
Fuel Pump Flow Test ........................ .
Fuel Pump Assembly ........................ .
Fuel Pump Relay .............................. ..
6C-1
6C-2
6C-3
6C-3
6C-4
6C-4
6C-5
6C-5
Fuel Tank .......................................... ..
Fuel Gage Unit ................................. ..
Fuel Filler Cap .................................... .
Accelerator Pedal Control ............... ..
Accelerator Pedal Control Cable ..
Accelerator Pedal ......................... .
Air
Cleaner Filter ........................... .
Main Data and Specifications ............... .
Torque Specifications ......................
..
6C-6
6C-7
6C-7
6C-8
6C-8
6C-9
6C-10
6C-11
6C-11
GENERAL DESCRIPTION
When working on the fuel system, there are several
things to keep in mind:
• Any time the fuel system is being worked on,
disconnect the negative battery
cable except for
those tests where battery voltage is required.
• Always keep a dry chemical (Class 8) fire extin­
guisher near the work area.
• Replace all pipes with the same pipe and fittings
that were removed.
• Clean and inspect "0" rings. Replace if required.
• Always relieve the line pressure before servicing
any fuel system components.
• Do not attempt repairs on the fuel system until you
have read the instructions and checked the pic­
tures
relating to that repair.
• Adhere to all Notices and Cautions.
All gasoline engines are designed to use only unleaded
gasoline. Unleaded gasoline
must be used for proper
emission control system operation. Its use will also
minimize spark plug fouling and extend engine oil life.
Using leaded gasoline can damage the emission
control system and could result in loss of emission
warranty coverage.
All cars are equipped with an Evaporative Emission
Control System. The purpose of the system is to
minimize the escape offuel vapors to the atmosphere.
Information on this system will be found in Section
6E2.

ENGINE FUEL 6C - 3
ON-VEHICLE SERVICE
When repair to the fuel system has been com­
pleted, start engine and check the fuel system for
FUEL FILTER
2
3
loose connection or leakage. For the fuel system
diagnosis, see Section 6E.
Receive rubber
Rer:noval steps 1. Fuel filler cap 2. Fuel hose
3. Fuel filter fixing bolt
4. Fuel filter
Installation steps To install, follow the removal steps in the
reverse order.
Fig. 6C-2
EJ REMOVAL
Preparation:
• Disconnect battery ground cable.
1. Fuel filler cap
2. Fuel hose
• Disconnect fuel hoses from fuel filter on both
engine side and fuel tank side.
3. Fuel filter fixing bolt
•
Remove the bolt on fuel filter holder.
4. Fuel filter
(1!] INSPECTION
1. Replace the fuel filter if the fuel leaks from fuel
filter body or if the fuel filter body itself is dam­
aged.
2. Replace the filter if it is clogged with dirt or
sediment.
3. Check the drain of receive rubber and if it is
clogged with dust, clean it up with air.
B INSTALLATION
4. Fuel filter
.......,. • Install the filter in the proper direction. (Fig.6C-
3)
Fig. 6C-3
3. Fuel filter holder fixing bolt.
2. Fuel hose
• Connect hoses on engine side and fuel tank
side.
1. Fuel filler cap
• Connect the battery ground cable.

6C -10 ENGINE FUEL
Adjustment of pedal stroke
Manual Transmission:
• Rotate counterclockwise to loosen the stopper
bolt sufficiently.
• Fully depress the pedal and hold it there hand.
Next, rotate the stopper bolt until it hits the
stopper of pedal bracket. Then, lock the stopper
bolt there.
Automatic Transmission:
• Rotate counterclockwise to loosen the kickdown
switch sufficiently.
• Fully depress the pedal and hold it there hand.
Rotate
the switch clockwise and then rotate
further by 1/2 turn from the position where the
switch clicks. Lock the switch there.
• Step on the accelerator pedal and make sure that
you can hear clicking sound at the full stroke
position.
AIR CLEANER FILTER
EJ REMOVAL
1. Air hose
2. Air cleaner cover
3. Air Cleaner Filter
(Fig.6C-12), (Fig.6C-13)
2. Air cleaner cover
3. Air Cleaner filter
(DOHC)
Fig. 6C-12
2. Air clearner cover
3.
Air Cleaner filter
(SOHC)
Fig. 6C-13
~ INSPECTION
Check the Air Cleaner filter for damage or dust clog­
ging. Replace if it is damaged, or clean if it is clogged.
Cleaning method
Hit the Air Cleaner filter gently with care not to dam­
age the paper filter, or clean the element by blowing
with compressed air of about 49kPa (71 psi) from the
clean side if it is extremely dirty.
Fig. 6C-14
8 INSTALLATION
3. Air Cleaner filter
2. Air cleaner cover
• Meet the cover to the body completely, then
clamp it with the clip.
1. Air cleaner hose
•

6E2-6 DRIVEABILITY AND EMISSIONS
FIELD SERVICE MODE
ENGINE
CONTROL MODULE (ECM)
LEARNING ABILITY
The Engine Control Module (ECM) has a
"learning"
ability which allows it to make
corrections
for minor variations in the fuel system
to improve driveability. If the battery is
disconnected to clear diagnostic codes, or for
repair, the "learning" process has to begin all over
again. A change
may be noted in the vehicle's
performance. To "teach" the vehicle, make sure
the engine is at operating temperature, and drive
at part throttle, with moderate acceleration and
idle conditions, until normal performance returns.
lfthe diagnostic test terminal is grounded with the
engine running, the system is in
"Open" or
"Closed Loop".
In "Open Loop" the "Check Engine" malfunction
indicator lamp flashes
two and one-halftimes per
seconds.
In "Closed Loop", the light flashes once per
second.
Also, in "Closed
Loop", the light will stay "OFF"
most of the time if the system is too lean. It will
stay"ON" mostofthetime if the system is too rich.
While the system is in Field Service Mode, the
ECM will be in the following diagnostic test mode:
1. New trouble codes cannot be stored in the
ECM.
2. The closed loop timer is bypassed.
STANDARD NOMENCLATURE FOR /
CERTAIN ELECTRICAL/ELECTRONIC COMPONENTS AND SYSTEMS /
Starting with the 1993 model, lsuzu Motors will be complying with the Society of Automotive ~ngineers
(SAE) Recommended Practice J 1930. J 1930 is an industry wide standard that was ad6pted into
government regulations and requires certain electrical and electronic components and
syster;ns be known
by the same
nomenclature that have the same function. This standard is also being applied to
abbreviations and acronyms.
This standard is being used in
all 1993 service publications.
To make this standard work, some names and abbreviations are being replaced
with those recommended
by the
SAE Standard. What follows is a partial listing of former ISUZU names and abbreviations besides
the
new ISUZU names and abbreviations.
Former ISUZU Name New ISUZU Name Term
3Gr
Third Gear -3GR
3rd Gear
Third Gear -3GR
4Gr
Fourth Gear -4GR
4th Gear
Fourth Gear -4GR
A/C Air Conditioning -A/C
A/C
Relay Air Conditioning Relay -A/C Relay
Absolute Presure Sensor
Manifofd Absolute Pressure Sensor -MAP Sensor
AC Air Conditioning -A/C
AC Generator . Generator -GEN
ACC Air Conditioning -A/C
Accel
Accelerator Pedal -AP
Accelerator
Accelerator Pedal -AP
ACG Generator -GEN
Air Cleaner Element(s) / Air Cleaner Filter -ACL Filter
Air Cleaner Filter Ele;nent Air Cleaner Filter -ACL Filter
Air Conditioning / Air Conditioning -A/C
Air Injection Reaction System Secondary Air Injection System -AIR System
ALDL Data Link Connector -
DLC
ALDL Diagnostic Connector DLC Diagnostic Connector -DLC Diagnostic Connector ,.
, ....

DRIVEABILITV AND EMISSIONS 6E2-53
CHART A-7
(P«ge 2 of 3)
FUEL SYSTEM PRESSURE TEST
NOTE: FUEL SYSTEM IS UNDER PRESSURE. TO AVOID FUEL SPILLAGE, REFER TO FIELD SERVICE PROCEDURES FOR TESTING OR REPAIRS
REQUIRING DISASSEMBLY OF FUEL LINES OR FITIINGS. REFER TO PAGE 3 OF 3 OF THIS CHART.
FROM CHART A-7 E!A:8E 1 PRESSURE OUT OF SPEC.
LOW PRESSURE I
(j) • CHECK FOR RESTRICTED IN-LINE FILTER. I IS FILTER OK?
® ~ $
• IGNITION "OFF"
REPLACE FILTER I • APPLY BATIERY POSITIVE AND RE-TEST.
VOLTAGE TO FUEL PUMP RELAY CONNECTOR USING A FUSED JUMPER
WIRE WITH FUEL PUMP RELAY
REMOVED.
• GRADUALLY BLOCK FUEL
RETURN LINE BY PINCHING
FLEXIBLE HOSE AND NOTE FUEL PRESSURE.
• FUEL PRESSURE SHOULD BE ABOVE 450 kPa (psi) IS IT?
~ $
FUEL PRESSURE CHECK IN-TANK PUMP
CONTROL VALVE ASSEMBLY FOR ASSEMBLY IS FAULTY.
-FAULTY FUEL PUMP -LEAKING COUPLING HOSE -INCORRECT PUMP. HIGH
PRESSURE
I
• DISCONNECT VACUUM LINE TO PRESSURE REGULATOR. • DISCONNECT FUEL RETURN LINE FLEXIBLE HOSE.
• ATIACH AS/16. I.D. FLEX HOSE TO PRESSURE REGULATOR SIDE OF RETURN LINE AND INSERT THE OTHER END INTO AN APPROVED GASOLINE
CONTAINER.
• NOTE FUEL PRESSURE WITHIN 2 SECONDS AFTER IGNITION IS TURNED "ON" • FUEL PRESSURE SHOULD BE 280-320 (41-46 PSI).
IS IT?
CfJ ~ FUEL PRESSURE LOCATE AND REPAIR
CONTROL VALVE RESTRICTED FUEL ASSEMBLY IS FAULTY. RETURN LINE.

FUEL SYSTEM
• CHECK:
• CHECK:
• CHECK:
• CHECK:
• CHECK:
• CHECK:
Fuel pump relay operation-pump should
turn "ON" for 2 seconds when ignition is
turned
"ON". Use CHART A-5.
Fuel injectors are correct for the vehicle.
Fuel
pressure, use CHART A-7.
Contaminated
fuel.
Engine fuse (visual inspect).
A
faulty in-tank fuel pump check valve will
allow
the fuel in the lines to drain back to
the tank after engine is stopped. To check
for this condition, perform fuel system
diagnosis CHART A-7.
IGNITION SYSTEM
• CHECK: For proper ignition voltage output with
spark tester J26792 or equivalent (ST-
125).
DRIVEABILITY AND EMISSIONS 6E2-91
• CHECK: Spark plugs. Remove spark plugs, check
for wet plugs, cracks, wear, improper
gap, burned electrodes, or heavy
deposits. Repair
or replace as necessary.
• CHECK: Bare or shorted wires.
• CHECK: Loose ignition coil ground.
ADDITIONAL CHECKS
• CHECK: Idle air control operation-use CHART C-
2C.
• CHECK: Basic engine problem. Refer to ENGINE
MECHANICAL DIAGNOSIS (SECTION
6A).
• CHECK: Service Bulletins for calibration updates.
SURGES AND/OR CHUGGLES
Definition: Engine power variation under steady
throttle or cruise. Feels like the car speeds
up and
slows down with no change in the
acceleration pedal.
PRELIMINARY CHECKS
• Perform the careful visual checks as described at
start
of "Symptoms," Section "6E2-B."
•
Be sure driver understands transmission
operation, and air conditioning compressor
operation
as explained in the owner's manual.
SENSORS
• CHECK: Heated oxygen sensor (H02S). The
H02S should respond quickly to different
throttle position, if it does not, check the
H02S for silicon or other contaminations
from fuel, or use of improper RTV sealant.
The sensor may have a white, powdery
coating and result in a high but false
signal voltage
(rich heated H02S signal
indication). The engine control module
will
then reduce the amount of fuel
delivered
to the engine, causing a severe
driveability problem. Also, watch for
green glycol contamination or cracking.
FUEL SYSTEM
• NOTICE: To determine ifthe condition is caused by
a rich
or lean system, the car should be
driven at the speed of the complaint.
Monitoring block learn will help identify a
problem.
Lean -Block learn above 142. Refer to
"Diagnostic Aids" on facing page of
diagnostic trouble code 44.
Rich -L.T. Fuel Trim above 118. Refer to
"Diagnostic Aids" on facing page of
diagnostic trouble code 45.
• CHECK: Fuel pressure while condition exists. Use
CHART A-7.
• CHECK: In-line fuel filter. Replace if dirty or
plugged.
IGNITION SYSTEM
• CHECK: For proper ignition voltage output using
spark tester (ST-125) J26792
or
equivalent .
• CHECK: Spark plugs. Remove spark plugs, check
for wet plugs, cracks, wear, improper
gap, burned electrodes, or heavy
deposits. Repair
or replace as necessary.
Also, check condition of electronic
ignition and spark plug wires.
• CHECK: Ignition timing. Using "Scan tool".
ADDITIONAL CHECKS
• CHECK: Engine control module grounds for being
clean, tight and in their proper location.
• CHECK: Vacuum lines for kinks or leaks.
• CHECK: Exhaust gas recirculation -There should
be no exhaust gas recirculation at idle.
Refer to CHART C-7.
• CHECK: Generator output voltage. Repair if less
than 9 or more than 16 volts.

6E2-92 DRIVEABILITY AND EMISSIONS
LACK OF POWER, SLUGGISH OR SPONGY
Definition: Engine delivers less than expected power.
Little or no increase in speed when
accelerator
pedal is pushed down part
way.
PRELIMINARY CHECKS
• Perform the careful visual/physical checks as
described at start of "Symptoms," Section "6E2-
B."
•
Compare customer's car to similar unit. Make sure
the
vehicle has an actual problem.
• Remove air filter and check air filter for dirt, or for
being plugged. Replace as necessary.
FUEL SYSTEM
• CHECK: Rescricted fuel filter.
• CHECK: Fuel pressure, use CHART A-7.
• CHECK: Contaminated fuel.
• CHECK: Fuel injectors are correct for the vehicle.
IGNITION SYSTEM
• CHECK: Ignition timing, using "Scan tool".
• CHECK: Knock sensor system for excessive spark
retard activity. Refer to CHART
C-5. Use
"Scan tool".
• CHECK: Secondary voltage using an oscilloscope
or a spark tester J 26792 (ST-125), or
equivalent, to check for a weak coil.
ADDITIONAL CHECKS
• CHECK: Engine control module grounds for being
clean,
tight and in their proper locations.
See engine control module wiring
diagrams.
• CHECK: Exhaust gas recirculation operation for
being open or partly open all the time.
- Refer to CHART
C-7.
• CHECK: Generator output voltage. Repair if less
than 9
or more than 16 volts.
• CHECK: Exhaust system for possible restriction.
Refer
to CHART B-1.
-Inspect exhaust system for damaged
or collapsed pipes.
-
Inspect muffler for heat damage or
possible internal failure.
• CHECK: Torque converter clutch for proper
operation. Refer
to AUTOMATIC
TRANSMISSION
(SECTION 7A).
ENGINE MECHANICAL
• CHECK: Engine valve timing and compression.
• CHECK: Engine for correct or worn camshaft.
Refer
to ENGINE MECHANICAL
DIAGNOSIS
(SECTION 6A).
DETONATION/SPARK KNOCK
Definition: A mild to severe ping, usually worse under
acceleration. The engine makes sharp
metallic knocks that change with throttle
opening.
Sounds like popcorn popping.
PRELIMINARY CHECKS
• Perform the careful visual/physical checks as
Low engine coolant.
Restricted air
flow to radiator, or restricted
water flow through radiator.
Correct engine
coolant solution should be a 50/
50 mix of anti-freeze engine coolant (or
equivalent) and water.
described at start
of "Symptoms," Section "6E2-FUEL SYSTEM
B."
•
Park/Neutral position switch. Be sure "Scan tool"
indicates drive with gear selector in drive or
overdrive. Use
CHART C-1A.
• If "Scan tool" readings are normal (see facing page
of on-board diagnostic system check) and there
are no engine mechanical faults,
fill fuel tank with a
gasoline
that has a minimum octane reading of 87
and revaluate vehicle performance.
• CHECK: Exhaust gas recirculation system for not
opening. Use CHART C-7.
COOLING SYSTEM
• Check for obvious overheating problems:
• NOTICE: To determine if the condition is caused by
a rich
or lean system, the car should be
driven at the speed
of the complaint.
Monitoring
LT. Fuel Trim will help
identify problem.
Lean-
LT. Fuel Trim above 142. Refer to
"Diagnostic Aids" on facing page of
diagnostic trouble code 44.
Rich-LT. Fuel Trim below 118. Refer to
"Diagnostic Aids" on facing page of
diagnostic trouble code 45.
• CHECK: Fuel pressure, use CHART A-7.
..