light ISUZU TF SERIES 2004 Workshop Manual

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–361
SYMPTOM DIAGNOSIS
PRELIMINARY CHECKS
Before using this section, perform the “On-Board
Diagnostic (OBD) System Check” and verify all of the
following items:
The engine control module (ECM) and check engine
lamp (MIL=malfunction indicator lamp are operating
correctly.
There are no Diagnostic Trouble Code(s) stored.
Tech 2 data is within normal operating range. Refer to
Typical Scan Data Values.
Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time. This check should include the following items:
ECM grounds for cleanliness, tightness and proper
location.
Vacuum hoses for splits, kinks, and proper
connection. Check thoroughly for any type of leak or
restriction.
Air intake ducts for collapsed or damaged areas.
Air leaks at throttle body mounting area, mass air flow
(MAF) sensor and intake manifold sealing surfaces.
Wiring for proper connections, pinches and cuts.
INTERMITTENT
Important: An intermittent problem may or may not turn
on the check engine lamp (MIL=malfunction indicator
lamp) or store a Diagnostic Trouble Code. Do NOT use
the Diagnostic Trouble Code (DTC) charts for
intermittent problems.
The fault must be present to locate the problem.
Most intermittent problems are cased by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions.
Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).
Improperly formed or damaged terminal.
All connector terminals in the problem circuit should
be carefully checked for proper contact tension.
Poor terminal-to-wire connection. This requires
removing the terminal form the connector body to
check.
Check engine lamp (MIL=malfunction indicator lamp)
wire to ECM shorted to ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Using Tech 2 to help detect intermittent conditions. The
Tech 2 have several features that can be used to
located an intermittent condition. Use the following
features to find intermittent faults:
To check for loss of diagnostic code memory,
disconnect the MAF sensor and idle the engine until the
check engine lamp (MIL=malfunction indicator lamp)
comes on. Diagnostic Trouble Code P0100 should be
stored and kept in memory when the ignition is turned
OFF.
If not, the ECM is faulty. When this test is completed,
make sure that you clear the Diagnostic Trouble Code
P0100 from memory.
An intermittent check engine lamp (MIL=malfunction
indicator lamp) with no stored Diagnostic Trouble Code
may be caused by the following:
Check engine lamp (MIL=malfunction indicator lamp)
wire to ECM short to ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.
Check for improper installation of electrical options such
as light, cellular phones, etc. Check all wires from ECM
to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).
If problem has not been found, refer to ECM connector
symptom tables.
Check the “Broadcast Code” of the ECM, and
compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
determine if an update to the ECM's reprogrammable
memory has been released.
This identifies the contents of the reprogrammable
software and calibration contained in the ECM.
If the “Broadcast Code” is not the most current
available, it is advisable to reprogram the ECM's
EEPROM memory, which may either help identify a
hard-to find problem or may fix the problem.
The Service Programming System (SPS) will not allow
incorrect software programming or incorrect calibration
changes.

6A-4 ENGINE MECHANICAL (6VE1 3.5L)
Engine Diagnosis
Hard Starting
1. Starting Motor Does Not Turn Over
Troubleshooting Procedure
Turn on headlights and starter switch.


Symptom Possible Cause Action
Headlights go out or dim considerably Battery run down or under charged Recharge or replace battery
Terminals poorly connected Clean battery posts and terminals
and connect properly
Starting motor coil circuit shorted Overhaul or replace
Starting motor defective Overhaul or replace

2. Ignition Trouble




Starting Motor Turns Over But
Engine Does Not Start Spark Test
Disconnect an ignition coil from any spark plug.
Connect the spark plug tester 5884003830, start the
engine, and check if a spark is generated in the spark
plug tester. Before starting the engine, make sure that
the spark plug tester is properly grounded. To avoid
electrical shock, do not touch the part where insulation
of the ignition coil is broken while the engine is running.


Symptom Possible Cause Action
Spark jumps across gap Spark plug defective Clean or replace
Ignition timing incorrect Refer to Ignition System
Fuel not reaching fuel injector(s) or
engine Refer to item 3 (Trouble in fuel
system)
Valve timing incorrect Adjust
Engine lacks compression Refer to item 4 (Engine lacks
compression)
No sparking takes place Ignition coil disconnected or broken Connect properly or replace
Electronic Ignition System with
module Replace
Poor connections in engine harness Correct
Engine Control Module cable
disconnected or defective Correct or replace

6A-12 ENGINE MECHANICAL (6VE1 3.5L)
Engine Noisy
Abnormal engine noise often consists of various noises
originating in rotating parts, sliding parts and othe
r
moving parts of the engine. It is, therefore, advisable to
locate the source of noise systematically.

Symptom Possible Cause Action
Noise from crank journals or from
crank bearings
(Faulty crank journals and crank
bearings usually make dull noise that
becomes more evident when
accelerating) Oil clearance increased due to worn
crank journals or crank bearings Replace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
Crankshaft out of round Replace crank bearings and
crankshaft or regrind crankshaft and
install the undersize bearing
Crank bearing seized Crank bearing seized Replace crank
bearings and crankshaft or regrind
crankshaft and install the undersize
bearing

Troubleshooting Procedure
Short out each spark plug in sequence using insulated
spark plug wire removers. Locate cylinder with defective
bearing by listening for abnormal noise that stops when
spark plug is shorted out.

Symptom Possible Cause Action
Noise from connecting rods or from
connecting rod bearings
(Faulty connecting rods or connecting
rod bearings usually make an
abnormal noise slightly higher than
the crank bearing noise, which
becomes more evident when engine
is accelerated) Bearing or crankshaft pin worn Replace connecting rod bearings and
crankshaft or regrind crankshaft pin
and install the undersize bearing
Crankpin out of round Replace connecting rod bearings and
crankshaft or regrind crankshaft pin
and install the undersize bearing
Connecting rod bent Correct or replace
Connecting rod bearing seized Replace connecting rod bearings and
crankshaft or regrind crankshaft pin
and install the undersize bearing

ENGINE MECHANICAL (6VE1 3.5L) 6A-29
Timing Belt
Removal
1. Disconnect battery ground cable.
2. Remove air cleaner assembly.
3. Remove radiator upper fan shroud from radiator.
4. Move drive belt tensioner to loose side using
wrench then remove drive belt.


850RW001
Legend
(1) Crankshaft Pulley
(2) Cooling Fan Pulley
(3) Tensioner
(4) Generator
(5) Air Conditioner Compressor
(6) Power Steering Oil Pump
(7) Drive Belt

5. Remove cooling fan assembly four nuts, then the
cooling fan assembly.
6. Remove cooling fan drive pulley assembly.
7. Remove idle pulley assembly.
8. Remove serpentine belt tensioner assembly.
9. Remove power steering pump assembly.
10. Remove crankshaft pulley assembly using
5884001330 crankshaft holder, hold crankshaf
t
pulley remove center bolt, then the pulley.
11. Remove right side timing belt cover then left side
timing belt cover.
12. Remove lower timing belt cover 13. Remove pusher.
CAUTION: The pusher prevents air from entering
the oil chamber. Its rod must always be facing
upward.




014RW011
Legend
(1) Up Side
(2) Down Side
(3) Direction For Installation
(4) Locking Pin

14. Remove timing belt.
CAUTION:
1. Do not bend or twist the belt, otherwise its
core could be damaged. The belt should not be
bent at a radius less than 30 mm.
2. Do not allow oil or other chemical substances
to come in contact with the belt. They will
shorten the life.
3. Do not attempt to pry or stretch the belt with a
screw driver or any other tool during
installation.
4. Store timing belt in a cool and dark place.
Never expose the belt direct sunlight or heat.

6C-8 ENGINE FUEL (6VE1 3.5L)
Fuel Tube / Quick – Connector Fittings
Precautions
 Do not light a match or create a flame.
 Keep flames away from your work area to preven
t
flammable materials from catching fire.
 Disconnect battery ground cable to preven
t
electrical shorts.
 Pre-treat piping system or associated parts from
thermal damage or from spattering when welding
or similar heat-generating work.
Cautions During Work




140R100032
Legend
(1) O-ring
(2) Port
(3) Connector
(4) Plastic Tube

Do not expose the assembly to battery electrolyte or do
not wipe the assembly with a cloth used to wipe off spil
t
battery electorolyte.
Piping that has been splattered with battery electrolyte
or battery electrolyte soaked cloth that was wiped on the
piping cannot be used.
Removal
1. Open the fuel cap to relieve the fuel pressure in the
tank.
Use compressed air to remove any dirt on the fuel
quick connect fittings prior to disconnecting the
fittings.




141R100002
When disconnecting the fuel pipe, cover the area
with a cloth to prevent fuel from splashing as the
fuel pipe may still have some pressure in it.
2. For removal of the quick connector, hold the quick
connector in one hand, and pull out the connento
r
with the other hand while pressing the square
relieve button of the connector, as illustrated.






140R100037
NOTE: Do not use tools of any kind. Only use bare
hands when disconnecting the connector. Use a
lubricant (light oil) and/or push and pull the connecto
r
until the pipe is disconnected.
Cover the connectors that was removed with a
plastic bag, to prevent dust or rain water from
entering.

ENGINE FUEL (6VE1 3.5L) 6C-9




140R100028
Reuse of Quick–Connector
 Replace the port and connector if scratch, dent or
crack is found.
 Remove any dirt build up on the port when installing
the connector. Replace the connector, if there is any
forms of rust, dent, scratch.
 After cleaning the port, insert it straight into the
connector until it clicks. After it clicks, try pulling a
t
49N (5kgf) it out to make sure that it is not drawn
and is securely locked.




140R100036

Assembling Advice
By applying engine oil or light oil to the pipe, port makes
pipe assembly easier. The pipe assembly should take
place immediately after applying oil (to prevent dus
t
from sticking to the pipe surface –which may
decrease sealing ability).
Test/Inspection After Assembling
1. Reconnect the battery negative cable.
2. Turn the ignition key to the “ON" position and listen
for pump start-up sound. Inspect for leaks, the
fuel pressure will increase as the fuel pump is
actuated.
3. Perform leak inspection (step 2) several times.
4. Start the engine and observe the engine idle speed.
The presence of dirt in the fuel system may affec
t
the fuel injection system.

6D1-4 ENGINE ELECTRICAL (6VE1 3.5L)
Jump Starting Procedure
1. Set the vehicle parking brake.
If the vehicle is equipped with an automatic
transmission, place the selector level in the “PARK"
position.
If the vehicle is equipped with a manual
transmission, place the shift lever in the
“ NEUTRAL" position.
Turn “OFF" the ignition.
Turn “OFF" all lights and any other accessory
requiring electrical power.
2. Look at the built –in hydrometer.
If the indication area of the built –in hydrometer is
completely clear, do not try to jump start.
3.
Attach the end of one jumper cable to the positive
terminal of the booster battery.
Attach the other end of the same cable to the
positive terminal of the discharged battery.
Do not allow the vehicles to touch each other. This
will cause a ground connection, effectively
neutralizing the charging procedure.
Be sure that the booster battery has a 12 volt rating.
4. Attach one end of the remaining cable to the
negative terminal of the booster battery.
Attach the other end of the same cable to a solid
engine ground (such as the air conditioning
compressor bracket or the generator mounting
bracket) of the vehicle with the discharged battery.
The ground connection must be at least 450 mm
(18 in.) from the battery of the vehicle whose battery
is being charged.
WARNING: NEVER ATTACH THE END OF THE
JUMPER CABLE DIRECTLY TO THE NEGATIVE
TERMINAL OF THE DEAD BATTERY.
5. Start the engine of the vehicle with the good battery.
Make sure that all unnecessary electrical
accessories have been turned “OFF".
6. Start the engine of the vehicle with the dead battery.
7. To remove the jumper cables, follow the above directions in reverse order.
Be sure to first disconnect the negative cable from
the vehicle with the discharged battery.


Battery Removal

P1010001

1. Remove negative cable.
2. Remove positive cable (2).
3. Remove retainer screw and rods.
4. Remove retainer.
5. Remove battery.
Battery Installation
1. Install battery.
2. Install retainer.
3. Install retainer screw and rods.
NOTE: Make sure that the rod is hooked on the body
side.
4. Install positive cable.
5. Install negative cable.

6D3-16 STARTING AND CHARGING SYSTEM (6VE1 3.5L)
Generator
Removal
1. Disconnect battery ground cable.
2. Move drive belt tensioner to loose side using
wrench then remove drive belt (1).
3. Disconnect the wire from terminal “B" and
disconnect the connector (4).
4. Remove generator fixing bolt (3).
5. Remove generator assembly (2).





060RW002
Inspection
1. Disconnect the wiring connector from generator.
2. With the engine stopped, turn starter switch to “ON"
and connect a voltmeter between connecto
r
terminal L (2) and ground or between terminal IG (1)
and ground.




066RW001
If voltage is not present, the line between battery
and connector is disconnected and so requires
repair.
3. Reconnect the wiring connector to the generator,
run the engine at middle speed, and turn off all
electrical devices other than engine.
4. Measure battery voltage. If it exceeds 16V, repair o
r
replace the generator.
5. Connect an ammeter to output terminal o
f
generator, and measure output current under load
by turning on the other electrical devices (eg.,
headlights). At this time, the voltage must not be
less than 13V.
Installation
1. Install generator assembly to the position to be
installed.
2. Install generator assembly and tighten the fixing
bolts to the specified torque.
Torque:
M10 bolt: 52 N




m (5.3 kg




m/38 lb ft)
M8 bolt: 25 N




m (2.5 kg




m/18 lb ft)
3. Connect wiring harness connector and direc
t
terminal “B".
4. Move drive belt tensioner to loose side using
wrench, then install drive belt to normal position.
5. Reconnect battery ground cable.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-31

RELAY AND FUSE BOX LOCATION (LHD & RHD)
RELAY & FUSE BOX

RELAY
NO. Relay name
X-1 RELAY; TAIL LIGHT
X-2 RELAY; FUEL PUMP
X-3 RELAY; HORN
X-4 RELAY; DIMMER
X-5 RELAY; FOG LIGHT
X-6 RELAY; STARTER
X-7 RELAY; COND, FAN
X-8 RELAY;

X-9 RELAY; HAZARD-RH
X-10 RELAY; HAZARD-LH
X-11 RELAY; HEATER
X-12 RELAY; HEAD LIGHT
X-13 RELAY; ECM MAIN
X-14 RELAY; A/C COMP
X-15 RELAY; THERMO


FUSE





 
 
 
 


  
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3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-59
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 o
f
combustion by products become sufficient to cause
misfiring. In some cases, these deposits may melt and
form a shiny glaze on the insulator around the cente
r
electrode. If the fouling is found in only one or two
cylinders, valve stem clearances or intake valve seals
may be allowing excess lubricating 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 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 fo
r
proper heat transfer and spark plug cooling. Dirty or
damaged threads in the head or on the spark plug can
keep 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. Over tightening may cause the
spark plug shell to be stretched and will result in poo
r
contact between the seats. In extreme cases, exhaus
t
blow-by and damage beyond simple gap wear may
occur.
Cracked or broken insulators may be the result o
f
improper installation, damage during spark plug 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 no
t
visible. Also, the breakage may not cause problems
until oil or moisture penetrates the crack later.