Fuel sensor ISUZU TF SERIES 2004 Repair Manual

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

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

6A-8 ENGINE MECHANICAL (6VE1 3.5L)
Hesitation
Symptom Possible Cause Action
Hesitation on acceleration Throttle Position Sensor adjustment
incorrect Replace throttle valve assembly
Throttle Position Sensor circuit open
or shorted Correct or replace
Excessive play in accelerator linkageAdjust or replace
Mass Airflow Sensor circuit open or
poor connections Correct or replace
Mass Airflow Sensor defective Replace
Intake Air Temperature (IAT) Sensor
circuit open or poor connections Correct or replace
IAT Sensor defective Replace
Hesitation at high speeds
(Fuel pressure too low) Fuel tank strainer clogged Clean or replace
Fuel pipe clogged Clean or replace
Fuel filter clogged Replace
Defective fuel pump system Check and replace
Fuel Pressure Control Valve leaking Replace
Hesitation at high speeds
(Fuel injector not working normally) Power supply or ground circuit for
Multiport Fuel Injection System
shorted or open Check and correct or replace
Fuel Injector defective Replace
Cable of Multiport Fuel Injection
System circuit open or poor
connections 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-15
Abnormal Combustion
Symptom Possible Cause Action
Trouble in fuel system Fuel pressure control valve defectiveReplace
Fuel filter clogged Replace
Fuel pump clogged Clean or replace
Fuel tank or fuel pipe clogged Clean or replace
Fuel injector clogged Clean or replace
Fuel pump relay defective Replace
Power supply cable for fuel pump
broken or poor connections Reconnect, correct or replace
Mass Airflow (MAF) Sensor circuit
open or defective Correct or replace
MAF Sensor defective Replace
Engine Coolant Temperature (ECT)
Sensor circuit open or shorted Correct or replace
ECT Sensor defective Replace
Throttle Position Sensor adjustment
incorrect Readjust
Throttle Position Sensor defective Replace
Throttle Position Sensor connector
poor connections Reconnect
Vehicle Speed Sensor cable poor
connections or defective Correct or replace
Vehicle Speed Sensor loosely fixed Fix tightly
Vehicle Speed Sensor in wrong
contact or defective Replace
Engine Control Module cable poor
connections or defective Correct or replace

6A-20 ENGINE MECHANICAL (6VE1 3.5L)
Malfunction Indicator Lamp
The instrument panel “CHECK ENGINE" Malfunction
Indicator Lamp (MIL) illuminates by self diagnostic
system when the system checks the starting of engine,
or senses malfunctions. ”CHECK ENGINE" MIL does
not illuminate at the starting of engine

Symptom Possible Cause Action
“CHECK ENGINE" MIL does not
illuminate at the starting of engine Bulb defective Replace
MIL circuit open Correct or replace
Command signal circuit to operate
self diagnostic system shorted Correct or replace
Engine Control Module (ECM) cable
loosely connected, disconnected or
defective Correct or replace
ECM defective Replace
“CHECK ENGINE" MIL illuminates,
and stays on Deterioration of heated oxygen
sensor internal element Replace
Heated oxygen sensor connector
terminal improper contact Reconnect properly
Heated oxygen sensor lead wire
shorted Correct
Heated oxygen sensor circuit open Correct or replace
Deterioration of engine coolant
temperature sensor internal element Replace
Engine coolant temperature sensor
connector terminal improper contact Reconnect properly
Engine coolant temperature sensor
lead wire shorted Correct
Engine coolant temperature sensor
circuit open Correct or replace
Throttle position sensor open or
shorted circuits Correct or replace
Deterioration of crankshaft position
sensor Replace
Crankshaft position sensor circuit
open or shorted Correct or replace
Vehicle speed sensor circuit open Correct or replace
Intake air temperature sensor circuit
open or shorted Correct or replace
Fuel injector circuit open or shorted Correct or replace
ECM driver transistor defective Replace ECM
Malfunctioning of ECM RAM
(Random Access Memory) or ROM
(Read Only Memory) Replace ECM

ENGINE MECHANICAL (6VE1 3.5L) 6A-21
Cylinder Head Cover LH
Removal
1. Disconnect battery ground cable.
2. Disconnect positive crankcase ventilation hose.
3. Remove camshaft angle sensor connector.
4. Remove ground cable fixing bolt on cylinder head
cover.
5. Ignition coil connector and ignition coil.

Disconnect the three connectors from the
ignition coils.

Remove harness bracket bolt on cylinder head
cover.

Remove fixing bolts on ignition coils.









060RW078
Legend
(1) Ignition Coil Connector
(2) Bolt
(3) Ignition Coil Assemblies

6. Remove fixing bolt for fuel injector harness
bracket.

7. Remove eight fixing bolts, then the cylinder head
cover.






010RW001
Installation
1. Install cylinder head cover.

Clean the sealing surface of cylinder head and
cylinder head cover to remove oil and sealing
materials completely.

Apply sealant (TB-1207B or equivalent) of bead
diameter 2-3 mm at eight place of arched area
of camshaft bracket on front and rear sides.

The cylinder head cover must be installed with
in 5 minutes after sealant application to preven
t
hardening of sealant.

Tighten bolts to the specified torque.
Torque : 9 N




m (0.9 kg




m/7 lb ft)




010RW006

6A-22 ENGINE MECHANICAL (6VE1 3.5L)
2. Install fuel injection harness bracket and tighten
bolt to the specified torque.
Torque : 8 N




m (0.8 kg




m/8 lb ft)
3. Connect ignition coil connector and ignition coil,
then tighten bolt to the specified torque.
Torque : 4 N




m (0.4 kg




m/3 lb ft)


060RW078
Legend
(1) Ignition Coil Connector
(2) Bolt
(3) Ignition Coil Assembly

4. Connect ground cable and tighten bolts to the
specified torque.
Torque : 8 N




m (0.8 kg




m/6 lb ft)
5. Connect camshaft angle sensor connector.
6. Install positive crankcase ventilation hose.