oil ISUZU TF SERIES 2004 Workshop Manual

ENGINE MECHANICAL (6VE1 3.5L) 6A-3
General Description
Engine Cleanliness And Care
An automobile engine is a combination of many
machined, honed, polished and lapped surfaces with
tolerances that are measured in the thousandths of a
millimeter (ten thousandths of an inch). Accordingly,
when any internal engine parts are serviced, care and
cleanliness are important. Throughout this section, i
t
should be understood that proper cleaning and
protection of machined surfaces and friction areas is
part of the repair procedure. This is considered
standard shop practice even if not specifically stated.


A liberal coating of engine oil should be applied to
all friction areas during assembly to protect and
lubricate the surfaces on initial operation.

Whenever valve train components, pistons, piston
rings, connecting rods, rod bearings, and
crankshaft journal bearings are removed fo
r
service, they should be retained in order.


At the time of installation, they should be installed
in the same locations and with the same mating
surfaces as when removed.

Battery cables should be disconnected before any
major work is performed on the engine. Failure to
disconnect cables may result in damage to wire
harness or other electrical parts.

The six cylinders of this engine are identified by
numbers; Right side cylinders 1, 3 and 5, Left side
cylinders 2, 4 and 6, as counted from crankshaf
t
pulley side to flywheel side.
General Information on Engine Service
The following information on engine service should be
noted carefully, as it is important in preventing damage
and contributing to reliable engine performance.

When raising or supporting the engine for any
reason, do not use a jack under the oil pan. Due to
the small clearance between the oil pan and the oil
pump strainer, jacking against the oil pan may
cause damage to the oil pick-up unit.

The 12-volt electrical system is capable o
f
damaging circuits. When performing any work
where electrical terminals could possibly be
grounded, the ground cable of the battery should
be disconnected at the battery.


Any time the intake air duct or air cleaner is
removed, the intake opening should be covered.
This will protect against accidental entrance o
f
foreign material into the cylinder which could
cause extensive damage when the engine is
started.
Cylinder Block
The cylinder block is made of aluminum die-cast casting
for 75Vtype six cylinders. It has a rear plate integrated
structure and employs a deep skirt. The cylinder liner is
cast and the liner inner diameter and crankshaft journal
diameter are classified into grades. The crankshaft is
supported by four bearings of which width is differen
t
between No.2, No.3 and No.1, No.4; the width of No.3
bearing on the body side is different in order to suppor
t
the thrust bearing. The bearing cap is made of nodular
cast iron and each bearing cap uses four bolts and two
side bolts.
Cylinder Head
The cylinder head, made of aluminum alloy casting
employs a pent-roof type combustion chamber with a
spark plug in the center. The intake and exhaust valves
are placed in V-type design. The ports are cross-flo
w
type.
Valve Train
Intake and exhaust camshaft on the both side of banks
are driven through an camshaft drive gear by timing
belt. The valves are operated by the camshaft and the
valve clearance is adjusted to select suitable thickness
shim.
Intake Manifold
The intake manifold system is composed of the
aluminum cast common chamber and intake manifold
attached with six fuel injectors.
Exhaust Manifold
The exhaust manifold is made of nodular cast iron.
Pistons and Connecting Rods
Aluminum pistons are used after selecting the grade
that meets the cylinder bore diameter. Each piston has
two compression rings and one oil ring. The piston pin
made of chromium steel is offset 1mm toward the thrus
t
side, and the thrust pressure of piston to the cylinder
wall varies gradually as the piston travels. The
connecting rods are made of forged steel. The
connecting rod bearings are graded for correct size
selection.
Crankshaft and Bearings
The crankshaft is made of Ductile cast-iron. Pins and
journals are graded for correct size selection for thei
r
bearing.
Engine Control Module (ECM)
The ECM location is on the common charmber.

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

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

ENGINE MECHANICAL (6VE1 3.5L) 6A-11
Symptom Possible Cause Action
Engine overheating Level of Engine Coolant too low Replenish
Fan clutch defective Replace
Thermostat defective Replace
Engine Coolant pump defective Correct or replace
Radiator clogged Clean or replace
Radiator filler cap defective Replace
Level of oil in engine crankcase too
low or wrong engine oil Change or replenish
Resistance in exhaust system
increased Clean exhaust system or replace
defective parts
Throttle Position Sensor adjustment
incorrect Replace with Throttle Valve ASM
Throttle Position Sensor circuit open
or shorted Correct or replace
Cylinder head gasket damaged Replace
Engine overcooling Thermostat defective Replace (Use a thermostat set to
open at 82
C (180
F))
Engine lacks compression ———— Refer to Hard Start
Others Tire inflation pressure abnormal Adjust to recommended pressures
Brake drag Adjust
Clutch slipping Adjust or replace
Level of oil in engine crankcase too
high Correct level of engine oil
EGR valve defective 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-17
Engine Oil Consumption Excessive
Symptom Possible Cause Action
Oil leaking Oil pan drain plug loose Retighten or replace gasket
Crankcase fixing bolts loosened Retighten
Oil pan setting bolts loosened Retighten
Oil pan gasket broken Replace gasket
Front cover retaining bolts loose or
gasket broken Retighten or replace gasket
Head cover fixing bolts loose or
gasket broken Retighten or replace gasket
Oil filter adapter cracked Replace
Oil filter attachings bolt loose or
rubber gasket broken Retighten or replace oil filter
Oil cooler broken Replace
Crankshaft front or rear oil seal
defective Replace oil seal
Oil pressure unit loose or broken Retighten or replace
Blow–by gas hose broken Replace hose
Positive Crankcase Ventilation Valve
clogged Clean
Engine/Transmission coupling failed Replace oil seal
Oil leaking into combustion chambers
due to poor seal in valve system Valve stem oil seal defective Replace
Valve stem or valve guide worn Replace valve and valve guide
Oil leaking into combustion chambers
due to poor seal in cylinder parts Cylinders and pistons worn
excessively Replace cylinder body assembly and
pistons
Piston ring gaps incorrectly
positioned Correct
Piston rings set with wrong side up Correct
Piston ring sticking Replace cylinder body assembly and
pistons
Piston ring and ring groove worn Replace pistons and others
Return ports in oil rings clogged Clean piston and replace rings
Positive Crankcase Ventilation
System malfunctioning Positive Crankcase Ventilation Valve
clogged Clean
Others Improper oil viscosity Use oil of recommended S.A.E.
viscosity
Continuous high speed driving and/or
severe usage such as trailer towing Continuous high speed operation
and/or severe usage will normally
cause increased oil consumption

6A-18 ENGINE MECHANICAL (6VE1 3.5L)
Fuel Consumption Excessive
Symptom Possible Cause Action
Trouble in fuel system Mixture too rich or too lean due to
trouble in fuel injection system Refer to “Abnormal Combustion"
Fuel cut function does not work Refer to “Abnormal Combustion"
Trouble in ignition system Misfiring or abnormal combustion due
to trouble in ignition system Refer to “Hard Start" or “Abnormal
Combustion"
Others Engine idle speed too high Reset to Section 6E
Returning of accelerator control
sluggish Correct
Fuel system leakage Correct or replace
Clutch slipping Correct
Brake drag Correct
Selection of transmission gear
incorrect Caution operator of incorrect gear
selection
Lubrication Problems
Symptom Possible Cause Action
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
bearing worn Replace
Oil contamination Wrong oil in use Replace with correct engine oil
Oil filter clogged Replace oil filter
Cylinder head gasket damage Replace gasket
Burned gases leaking Replace piston and piston rings or
cylinder body assembly
Oil not reaching valve system Oil passage in cylinder head or
cylinder body clogged Clean or correct

ENGINE MECHANICAL (6VE1 3.5L) 6A-19
Engine Oil Pressure Check
1. Check for dirt, Fuel or water in the engine oil.
a. Check the viscosity of the oil.
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 gauge.
5. Start the engine and allow the engine to reach
normal operating temperature (About 80C).
6. Measure the oil pressure.
Oil pressure should be:
392




550 kPa (56.9




80.4 psi) at 3000 rpm.
7. Stop the engine.
8. Remove the oil pressure gauge.
9. Install the oil pressure unit.
10. Start the engine and check for leaks.