2004 ISUZU TF SERIES spark plugs

ENGINE MECHANICAL (6VE1 3.5L) 6A-5
3. Trouble In Fuel System
Symptom Possible Cause Action
Starting motor turns over and spark
occurs but engine does not start. Fuel tank empty Fill
Water in fuel system Clean
Fuel filter clogged Replace filter
Fuel pipe clogged Clean or replace
Fuel pump defective Replace
Fuel pump circuit open Correct or replace
Evaporative Emission Control System
circuit clogged Correct or replace
Multiport Fuel Injection System faultyRefer to “Electronic Fuel Injection"
section

4. Engine Lacks Compression
Symptom Possible Cause Action
Engine lacks compression Spark plug loosely fitted Tighten to specified torque
Valve timing incorrect Adjust
Cylinder head gasket defective Replace gasket
Valve incorrectly seated Lap valve
Valve stem seized Replace valve and valve guide
Valve spring weakened or broken Replace
Cylinder or piston rings worn Overhaul engine
Piston ring seized Overhaul engine.

Engine Compression Test Procedure
1. Start and run the engine until the engine reaches
normal operating temperature.
2. Turn the engine off.
3. Remove all the spark plugs.
4. Remove ignition coil fuse (15A) and disable the
ignition system.
5. Remove the fuel pump relay from the relay and
fuse box.
6. Engage the starter and check that the cranking
speed is approximately 300 rpm.
7. Install cylinder compression gauge into spark plug
hole.
8. With the throttle valve opened fully, keep the
starter engaged until the compression gage needle
reaches the maximum level. Note the reading.
9. Repeat the test with each cylinder.
If the compression pressure obtained falls belo
w
the limit, engine overhaul is necessary.
Limit; 1000 kPa (145 psi)

ENGINE MECHANICAL (6VE1 3.5L) 6A-7
Rough Engine Running
Symptom Possible Cause Action
Engine misfires periodically Ignition coil layer shorted Replace
Spark plugs fouling Clean or install hotter type plug
Spark plug(s) insulator nose leaking Replace
Fuel injector(s) defective Replace
Engine control module faulty Replace
Engine knocks periodically Spark plugs running too hot Install colder type spark plugs
Engine control module faulty Replace
Engine lacks power Spark plugs fouled Clean
Fuel injectors defective Replace
Mass Airflow Sensor or Intake Airflow
Sensor circuit defective Correct or replace
Engine Coolant Temperature Sensor
or Engine Coolant Temperature
Sensor circuit defective Correct or replace
Engine Control Module faulty Replace
Intake Air Temperature Sensor or
Intake Air Temperature Sensor circuit
defective Correct or replace
Throttle Position Sensor or Throttle
Position Sensor circuit defective Correct or replace

6A-10 ENGINE MECHANICAL (6VE1 3.5L)
Engine Lacks Power
Symptom Possible Cause Action
Trouble in fuel system Fuel Pressure Control Valve not
working normally Replace
Fuel injector clogged Clean or replace
Fuel pipe clogged Clean
Fuel filter clogged or fouled Replace
Fuel pump drive circuit not working
normally Correct or replace
Fuel tank not sufficiently breathing
due to clogged Evaporative Emission
Control System circuit Clean or replace
Water in fuel system Clean
Inferior quality fuel in fuel system Use fuel of specified octane rating
Engine Control Module supplied poor
voltage Correct circuit
Throttle Position Sensor cable broken
or poor connections Correct or replace
Throttle Position Sensor defective Replace
Mass Airflow Sensor not working
normally Replace
Manifold Absolute Pressure Sensor
not working normally Replace
Intake Air Temperature Sensor not
working normally Replace
Engine Coolant Temperature Sensor
circuit open or shorted Correct or replace
Engine Coolant Temperature Sensor
defective Replace
Engine Control Module defective Replace
Trouble in intake or exhaust system Air Cleaner Filter clogged Replace filter element
Air duct kinked or flattened Correct or replace
Exhaust system clogged Correct or replace
Ignition failure ———— Refer to Hard Start Troubleshooting
Guide
Heat range of spark plug inadequateInstall spark plugs of adequate heat
range
Ignition coil defective Replace

6A-14 ENGINE MECHANICAL (6VE1 3.5L)
Troubleshooting Procedure
The slapping sound stops when spark plug on bad
cylinder is shorted out.

Symptom Possible Cause Action
Timing belt noise Timing belt tension is incorrect Replace pusher or adjust the tension
pulley or replace timing belt
Tensioner bearing defective Replace
Timing belt defective Replace
Timing pulley defective Replace
Timing belt comes in contact with
timing cover Replace timing belt and timing cover
Valve noise Valve clearance incorrect Replace adjusting shim
Valve and valve guide seized Replace valve and valve guide
Valve spring broken or weakened Replace
Valve seat off–positioned Correct
Camshaft worn out Replace
Crankshaft noise Crankshaft end play excessive (noise
occurs when clutch is engaged) Replace thrust bearing
Engine knocking Preignition due to use of spark plugs
of inadequate heat range Install Spark Plugs of adequate heat
range
Carbon deposits in combustion
chambers Clean
Fuel too low in octane rating Replace fuel
Wide Open Throttle enrichment
system failure Refer to Section 6E
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Engine overheating Refer to “Engine Lacks Power"
Others Water pump defective Replace
Drive belt slipping Replace auto tentioner or drive belt

ENGINE MECHANICAL (6VE1 3.5L) 6A-53
Disassembly
NOTE:

During disassembly, be sure that the valve train
components are kept together and identified so
that they can be reinstalled in their original
locations.

Before removing the cylinder head from the engine
and before disassembling the valve mechanism,
perform a compression test and note the results.
1. Remove camshaft drive gear pulley fixing bolt (3),
then pulley (4).
2. Remove camshaft bracket fixing bolt (5), camshaf
t
bracket (6), then camshaft exhaust (7), and intake
side (8).
3. Remove tappet with shim (11).
4. Use the 5884024460 valve spring compresso
r
and 5884025470 valve spring compressor
adapter to remove the split collar (12), valve spring
with upper seat (13) and valve (14).



014RW042
5. Remove spark plug (1).
CAUTION: Do not remove the spark plugs when the
head and plugs are hot. Clean dirt and debris from
spark plug recess areas before removal.
Clean
Cylinder head
Carefully remove all varnish, soot and carbon from the
bare metal. Do not use a motorized wire brush on any
gasket sealing surface.


Inspection and Repair
1. Cylinder head gasket and mating surfaces for
leaks, corrosion and blow-by. If the gasket has
failed, determine the cause.
Insufficient torque on head bolts
Improper installation
Loose or warped cylinder head
Missing dowel pins
Warped case surface
2. Cylinder head for cracks, especially between valve
seats and in the exhaust ports.
3. Cylinder head deck for corrosion, sand particles in
head and porosity.
CAUTION:

  Do not attempt to weld the cylinder head.
Replace it.

  Do not reuse cylinder head bolts.
4. Cylinder head deck, common chamber and
exhaust manifold mating surfaces for flatness.
These surfaces may be reconditioned by milling. I
f
the surfaces are “out of flat" by more than
specification, the surface should be ground to
within specifications. Replace the head if i
t
requires machining beyond the repairable limit.
Head surface and manifold surface
Standard: 0.05 mm (0.002 in) or less
Warpage limit: 0.2 mm (0.0079 in)
Maximum Repairable limit: 0.2 mm (0.0079 in)
Head height
Standard height : 133.2 mm (5.2441 in)
Warpage limit : 0.2 mm (0.0079 in)
Maximum Repairable limit : 133.0 mm (5.2362
in)



011RW019

6A-54 ENGINE MECHANICAL (6VE1 3.5L)
5. Water jacket sealing plugs seating surfaces.
Reassembly
1. Install spark plug and tighten all the spark plugs to
specified torque.
Torque: 18 Nm (1.8 kgm/13 lb ft)
2. Tighten sub gear setting bolt.
1. Use 5884024430 gear spring lever to turn
sub gear to right direction until the M5 bol
t
aligns with the hole between camshaft driven
gear and sub gear.
2. Tighten the M5 bolt to a suitable torque to
prevent the sub gear from moving.



014RW041
3. Install camshaft drive gear assembly and tighten
three bolts to the specified torque.
Torque: 10 N




m (1.0 kg




m/7 lb ft)
4. Install camshaft assembly and camshaft brackets,
tighten twenty bolts on one side bank to the
specified torque.
1. Apply engine oil to camshaft journal and
bearing surface of camshaft bracket.
2.
Align timing mark on intake camshaft (one dot
for right bank, two dots for left bank) and
exhaust camshaft (one dot for right bank, two
dots for left bank) to timing mark on camshaf
t
drive gear (one dot).







014RW020
Legend
(1) Intake Camshaft Timing Gear for Right Bank
(2) Intake Camshaft Timing Gear for Left Bank
(3) Exhaust Camshaft Timing Gear
(4) Discrimination Mark
LI: Left Bank Intake
RI: Right Bank Intake
LE: Left Bank Exhaust
RE: Right Bank Exhaust



014RW023
Legend
(1) Right Bank Camshaft Drive Gear
(2) Left Bank Camshaft Drive Gear
(3) Timing Mark on Drive Gear
(4) Dowel Pin

IGNITION SYSTEM (6VE1 3.5L) 6D2-1
ENGINE
IGNITION SYSTEM (6VE1 3.5L)
CONTENTS

Service Precaution................................................. 6D2-1
General Description............................................... 6D2-2
Diagnosis................................................................. 6D2-2
Ignition Coil.............................................................. 6D2-3
Removal............................................................... 6D2-3
Inspection and Repair........................................ 6D2-3
Installation............................................................ 6D2-3
Spark Plug............................................................... 6D2-4
Inspection............................................................. 6D2-4
Replacement spark plugs................................... 6D2-4
Crankshaft Position Sensor................................... 6D2-5
Removal................................................................ 6D2-5
Installation............................................................. 6D2-5
Main Data and Specifications................................ 6D2-6


Service Precaution
WARNING: THIS VEHICLE HAS 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, REFE
R
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, o
r
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.

6D2-2 IGNITION SYSTEM (6VE1 3.5L)
General Description
Ignition is done by the electronic ignition (El) that directly
fires the spark plugs from ignition coils through spark
plug wires without using a distributor. A pair of ignition
coils for the cylinders having different phases by 360

(No.1 and No.4, No.2 and No.5, No.3 and No.6) are
fired simultaneously.
Since the cylinder on exhaust stroke requires less
energy to fire its ignition plug, energy from the ignition
coils can be utilized to fire the mating cylinder on
compression stroke. After additional 360
rotation,
respective cylinder strokes are reversed.
The EI consists of six ignition coils, crankshaft position
sensor, engine control module (ECM) and othe
r
components.
The ignition coils are connected with the ECM.
The ECM turns on/off the primary circuit of ignition coils,
and also it controls the ignition timing.
A notch in the timing disc on the crankshaft activates
the crankshaft position sensor which then sends
information such as firing order and starting timing o
f
each ignition coil to the ECM.
Further, the El employs ignition control (IC) to control
similar to a distributor system.
Diagnosis
Refer to Section Drivability and Emissions for the
diagnosis to electronic ignition system (El system).