ignition ISUZU TF SERIES 2004 Workshop Manual

6E–408 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
12 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?—Go to Step 13Go to Step 30
13 Replace the MAF & IAT sensor assembly.
Is the action complete?—Veri fy repai r—
14 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Glow Time Relay” in the data display.
Does the Tech 2 indicate correct “Glow Time Relay”
status depending on the time from engine “Run”?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 30Go to Step 15
15 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Glow Time Relay” in the data display
and then, does the supply voltage correctly supply
to the glow plug?
—Go to Step 16Repair voltage
supply circuit
and verify repair
16 Check the glow plugs for continuity.
If a problem is found, repair as necessary.
Was a problem found?
—Verify repair Go to Step 17
17 Remove the CKP sensor from the flywheel housing
and check for the following conditions.
Objects sticking the CKP sensor.
Objects sticking the CKP sensor pulser.
If a problem is found, repair as necessary.
Was the problem found? —Verify repair Go to Step 18
18 Check the CKP sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 19 Step Action Value(s) Yes No

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–409
19 Substitute a known good CKP sensor and recheck.
Was the problem solved?—Go to Step 20Go to Step 21
20 Replace the CKP sensor.
Is the action complete?—Veri fy repai r—
21 1. Using the Tech 2 and ignition “On” and engine
“Run”.
2. Monitor the following parameters in the data
display.
“Desired Injection Quantity” & “Injection Quantity”
“Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?
—Go to Step 23Go to Step 22
22 Check the ex haust system for a possible restriction.
Damaged or collapsed pipes or catalytic converter.
Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 23
23 Visually/physically inspect for the following conditions.
Restrict fuel supply system. Check for a pinched
fuel hose/pipe.
Check for a condition that causes fuel wax ing or
icing, such as the customer is using an incorrect
fuel type in winter season or water mix ed with the
fuel.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 24
24 Replace the fuel filter.
Was the problem solved?—Verify repair Go to Step 25 Step Action Value(s) Yes No
When idling or part-throttle When accelerated


HighDesi red
Low
Ti m e Actu al
High
LowDe si red
Actu al
Time

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–413
EXCESSIVE BLACK SMOKE
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visually/physical check performed?
—Go to Step 4Go to Visual /
physical Check
4 Is the customer using the incorrect fuel type? Diesel fuel
onlyReplace with
diesel fuel Go to Step 5
5 Visually/physically inspect for the following conditions.
Restrict air intake system. Check for a restricted air
filter element, or foreign objects blocking the air
intake system
Check for objects blocking or ex cessive deposits in
the throttle bore and on the throttle plate
Check for a condition that causes a large vacuum
leak, such as an incorrectly installed or faulty
crankcase ventilation hose.
Restrict air intake system at the turbocharger.
Check for objects blocking the turbocharger
compressor wheel or turbine shaft sticking.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 6
6 Check the ECM & PSG grounds to verify that they are
clean and tight. Refer to the ECM wiring diagrams.
Was a problem found?—Verify repair Go to Step 7
7 1. Using the Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 8
8 1. Using the Tech 2, display the FT sensor value.
2. Check the displayed value.
Does the Tech 2 indicate correct temperature
depending on engine condition?
If a problem is found, repair as necessary.
Was the problem found?—Go to Step 21Go to Step 9
9 1. Using the Tech 2, ignition “On” and engine “Run”.
2. Monitor the “Mass Air Flow” in the data display.
Does the Tech 2 indicate correct “Mass Air Flow”
depending on accelerator pedal operation? —Go to Step 14Go to Step 10

6E–414 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
10 Remove the MAF & IAT sensor assembly and check
for the following conditions.
Objects blocking at the MAF sensor element.
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 11
11 Check the MAF sensor harness for the following
conditions.
Check for poor connector connection.
Check for misrouted harness.
Check for any accessory parts which may cause
electric interference.
If a problem is found, repair as necessary.
Was a problem found? —Verify repair Go to Step 12
12 Substitute a known good MAF & IAT sensor assembly
and recheck.
Was the problem solved?—Go to Step 13Go to Step 21
13 Replace the MAF & IAT sensor assembly.
Is the action complete?—Veri fy repai r—
14 1. Using the Tech 2 and ignition “On” and engine
“Run”.
2. Monitor the following parameters in the data
display.
“Desired Injection Quantity” & “Injection Quantity”
“Desired Injection Start” & “Actual Injection Start”
Are the large gap or unstable parameter displayed
between “Desired” and “Actual”?
—Go to Step 20Go to Step 15 Step Action Value(s) Yes No
When idling or part-throttle When accelerated


HighD esired
Low
Ti m e Actu al
High
LowD esired
Actual
Tim e

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–415
15 Using the Tech 2 or the vacuum pump and check the
EGR valve operation for the following condition
through the small window.
ÅERestrict shaft movement. Check for objects sticking
the shaft, broken diaphragm or ex cessive carbon
deposit.
Tech 2:
1. Using the Tech 2, ignition "On" and engine "On".
2. Select the "Miscellaneous Test" and perform the
"EGR Solenoid Test" in the "Solenoid".
3. Operate the Tech 2 in accordance with procedure.
Solenoid 95%: EGR Valve Open
Solenoid 5%: EGR Valve Close
Vacuum Pump:
1. Using the vacuum pump. Disconnect the original
vacuum hose and connect the hose to the EGR
valve.
2. Apply vacuum pressure.
Vacuum Apply: EGR Valve Open
Vacuum Release: EGR Valve Close
If a problem is found, repair as necessary.
Was the problem found?—Verify repair Go to Step 16
16 Check the ex haust system for a possible restriction.
Damaged or collapsed pipes or catalytic converter.
Internal muffler failure.
If a problem is found, repair as necessary.
Was a problem found?—Verify repair Go to Step 17 Step Action Value(s) Yes No

Vacuum Pump Small Window

ENGINE MECHANICAL (6VE1 3.5L) 6A-1
ENGINE
CONTENTS
Engine Mechanical.................................................6A
Engine Cooling........................................................6B
Engine Fuel.............................................................6C
Engine Electrical.....................................................6D1
Ignition System.......................................................6D2
Starting and Changing System.............................6D3 Driveability and Emissions.....................................6E
Engine Exhaust.......................................................6F
Engine Lubrication..................................................6G
Engine Speed Control System..............................6H
Induction...................................................................6J


ENGINE MECHANICAL (6VE1 3.5L)
CONTENTS

Service Precaution................................................. 6A-2
General Description............................................... 6A-3
Engine Diagnosis.................................................... 6A-4
Cylinder Head Cover LH........................................ 6A-21
Removal............................................................... 6A-21
Installation............................................................ 6A-21
Cylinder Head Cover RH....................................... 6A-23
Removal............................................................... 6A-23
Installation............................................................ 6A-23
Common Chamber................................................. 6A-24
Removal............................................................... 6A-24
Installation............................................................ 6A-25
Exhaust Manifold LH.............................................. 6A-26
Removal............................................................... 6A-26
Installation............................................................ 6A-26
Exhaust Manifold RH............................................. 6A-27
Removal............................................................... 6A-27
Installation............................................................ 6A-27
Crankshaft Pulley................................................... 6A-28
Removal............................................................... 6A-28
Installation............................................................ 6A-28
Timing Belt.............................................................. 6A-29
Removal............................................................... 6A-29
Installation............................................................ 6A-30
Camshaft................................................................. 6A-34
Removal............................................................... 6A-34
Installation............................................................ 6A-34
Cylinder Head......................................................... 6A-37
Removal............................................................... 6A-37
Installation............................................................ 6A-37
Valve Stem Oil Controller , Valve Spring
and Valve Guide.................................................... 6A-39
Removal................................................................ 6A-39
Installation............................................................. 6A-39
Piston, Piston Ring and Connecting Rod............ 6A-40
Removal................................................................ 6A-40
Installation............................................................. 6A-41
Crankshaft and Main Bearings.............................. 6A-43
Removal................................................................ 6A-43
Installation............................................................. 6A-44
Rear Oil Seal........................................................... 6A-48
Removal................................................................ 6A-48
Installation............................................................. 6A-48
Engine Assembly.................................................... 6A-49
Removal................................................................ 6A-49
Installation............................................................. 6A-49
Cylinder Head.......................................................... 6A-52
Cylinder Head and Associated Parts................ 6A-52
Disassembly......................................................... 6A-53
Clean..................................................................... 6A-53
Inspection and Repair......................................... 6A-53
Reassembly.......................................................... 6A-54
Valve Spring, Oil Controller, Valve, Valve
Guide....................................................................... 6A-56
Valve Spring, Oil Controller, Valve, Valve
Guide and Associated Parts............................. 6A-56
Disassembly......................................................... 6A-57
Inspection and Repair......................................... 6A-57
Reassembly.......................................................... 6A-61
Camshaft.................................................................. 6A-64
Camshaft and Associated Parts........................ 6A-64
Disassembly......................................................... 6A-64
Inspection and Repair......................................... 6A-65
Reassembly.......................................................... 6A-67

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)

6A-6 ENGINE MECHANICAL (6VE1 3.5L)
Rough Engine Idling or Engine Stalling
Symptom Possible Cause Action
Trouble in fuel injection system Idle air control valve defective Replace
Throttle shutting off incomplete Replace
Throttle position sensor circuit open
or shorted Correct or replace
Fuel injector circuits open or shortedCorrect or replace
Fuel injectors damaged Replace
Fuel pump relay defective Replace
Mass Airflow Sensor circuit open or
poor connections Correct or replace
Mass Airflow Sensor defective Replace
Engine Coolant Temperature Sensor
circuit open or poor connections Correct or replace
Engine Coolant Temperature Sensor
defective Replace
Intake Air Temperature sensor circuit
open or poor connections Correct or replace
Intake Air Temperature sensor
defective Replace
Vehicle Speed Sensor circuit open or
shorted Correct or replace
Vehicle Speed Sensor defective Replace
Trouble in emission control system EGR valve defective Replace
EGR valve circuit open or poor
connection Correct or replace
Engine Control Module defective Replace
Canister purge valve circuit open or
poor connections Correct or replace
Canister purge valve defective Replace
Evaporative Emission Canister Purge
control valve defective Replace
Trouble in ignition system Refer to “Hard Start"
Others Engine lacks compression Refer to “Hard Start"
Valve incorrectly seated Lap valve
Air Cleaner Filter clogged Replace filter element
Valve timing incorrect Readjust
Idle air control valve broken Replace
Fast idle solenoid defective Replace
Positive Crankcase Ventilation valve
defective or clogged Replace

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