2004 ISUZU TF SERIES spark plugs

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-339
Step Action Value (s) Yes No
12
Check the fuel control Heated Oxygen Sensor
(HO2S). When monitored on the Tech 2, the HO2S
should respond quickly to different throttle positions. If
it doesn't check for silicon or other contaminates from
fuel or use of improper sealant. The sensors may have
a white powdery coating. Silicon contamination sends
a rich exhaust signal which causes the ECM to
command and excessively lean air/fuel mixture.
Was a problem found?
- Verify repair Go to Step 13
13
Check the fuel pressure. Refer to Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 14
14
Perform the procedure in Fuel System Pressure Test
to determine if there is a problem with fuel delivery.
Refer to 6E-116 page.
Was a problem found?
- Verify repair Go to Step 15
15
Monitor "B1S1 (Bank 1 Sensor 1) Status" and "B2S1
(Bank 2 Sensor 1) Status" on the Tech 2.
Is the "B1S1 (Bank 1 Sensor 1) Status" or "B2S1
(Bank 2 Sensor 1) Status" in the rich condition?
- Go to Step 16 Go to Step 17
16
Check items that can cause the engine to run rich.
Refer to DTC P0172 "O2 Sensor System Too Rich
(Bank 1)" or DTC P0175 "O2 Sensor System Too Rich
(Bank 2)".
Was a problem found?
- Verify repair Go to Step 18
17
Check items that can cause the engine to run lean.
Refer to DTC P0171 "O2 Sensor System Too Lean
(Bank 1)" or DTC P0174 "O2 Sensor System Tool
Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 18
18
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 19
19
Check the ignition coils for cracks or carbon tracking.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 20
20
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 21
21
1. Check the injector connectors.
2. If any of the connectors are connected at an
improper cylinder, connect as necessary.
Was a problem found?
- Verify repair Go to Step 22

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-343
Step Action Value (s) Yes No
13
Check items that can cause the engine to run rich.
Refer to DTC P0172 "O2 Sensor System Too Rich
(Bank 1)" or DTC P0175 "O2 Sensor System Too Rich
(Bank 2)".
Was a problem found?
- Verify repair Go to Step 15
14
Check items that can cause the engine to run lean.
Refer to DTC P0171 "O2 Sensor System Too Lean
(Bank 1)" or DTC P0174 "O2 Sensor System Tool
Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 15
15
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 16
16
Check the ignition coils for cracks or carbon tracking.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 17
17
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 18
18
1. Check the injector connectors.
2. If any of the connectors are connected at an
improper cylinder, connect as necessary.
Was a problem found?
- Verify repair Go to Step 19
19
Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams.
Was a problem found?
- Verify repair Go to Step 20
20
Visually/physically check the vacuum hose for splits,
kinks and proper connections and routing.
Was a problem found?
- Verify repair Go to Step 21
21
Check the exhaust system for a possible restriction:

Damaged or collapsed pipes.

Internal muffler failure.
Was a problem found?
- Verify repair Go to Step 22

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-347
Step Action Value (s) Yes No
13
Check items that can cause the engine to run rich.
Refer to DTC P0172 "O2 Sensor System Too Rich
(Bank 1)" or DTC P0175 "O2 Sensor System Too Rich
(Bank 2)".
Was a problem found?
- Verify repair Go to Step 15
14
Check items that can cause the engine to run lean.
Refer to DTC P0171 "O2 Sensor System Too Lean
(Bank 1)" or DTC P0174 "O2 Sensor System Tool
Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 15
15
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 16
16
Check the ignition coils for cracks or carbon tracking.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 17
17
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 18
18
1. Check the injector connectors.
2. If any of the connectors are connected at an
improper cylinder, connect as necessary.
Was a problem found?
- Verify repair Go to Step 19
19
Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams.
Was a problem found?
- Verify repair Go to Step 20
20
Visually/physically check the vacuum hose for splits,
kinks and proper connections and routing.
Was a problem found?
- Verify repair Go to Step 21
21
Check the exhaust system for a possible restriction:

Damaged or collapsed pipes.

Internal muffler failure.
Was a problem found?
- Verify repair Go to Step 22

6E-350 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
9
1. Using the Tech 2, ignition "On" and engine "Off".
2. Monitor the "Throttle Position" in the data display.
Does the Tech 2 indicate correct "Throttle Position"
from 0% to 100% depending on accelerator pedal
operation?
- Go to Step 11 Go to Step 10
10
1. Using the Tech 2, ignition "On" and engine "Off".
2. Monitor the "Throttle Position" in the data display.
3. Adjust the accelerator cable or TPS within 0% to
100%.
Is the action complete?
- Verify repair -
11
Check for the following conditions.

Objects blocking the throttle valve.

Vacuum leaking at throttle body.
If a problem is found, repair as necessary.
Was the problem found? - Verify repair Go to Step 12
12
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 the IAC passage or
throttle bore, excessive 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/brake booster hose.
Was a problem found?
- Verify repair Go to Step 13
13
Perform the Injector Coil/Balance Test.
Refer to 6E-106 page
Was a problem found.
- Verify repair Go to Step 14
14
1. Check for fuel in the pressure regulator vacuum
hose.
2. If fuel is present, replace the fuel pressure regulator
assembly.
Was a problem found?
- Verify repair Go to Step 15
15
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 16
16
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 17

6E-354 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
15
Check items that can cause the engine to run lean. Refer to
DTC P0171 "O2 Sensor System Too Lean (Bank 1)" or DTC
P0174 "O2 Sensor System Tool Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 16
16
Check for proper ignition voltage output with the spark tester.
Was a problem found?
- Verify repair Go to Step 17
17
Check the ignition coils for cracks or carbon tracking. If a
problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 18
18
1. Remove the spark plugs and check for gas or oil fouling
cracks, wear, improper gap, burned electrodes, heavy
deposits, or improper heat range.
2. If spark plugs are fouled, the cause of fouling must be
determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 19
19
Visually/physically check the vacuum hose for splits, kinks and
proper connections and routing.
Was a problem found?
- Verify repair Go to Step 20
20
Check the exhaust system for a possible restriction:

Damaged or collapsed pipes.

Internal muffler failure.
Was a problem found?
- Verify repair Go to Step 21
21
Check the torque converter clutch (TCC) for proper operation
(if A/T model). If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 22
22
Check for the following engine mechanical problems (refer to
Engine Mechanical Section):

Low compression.

Leaking cylinder head gaskets.

Worn camshaft.

Sticking or leaking valves.

Valve timing.

Broken valve springs.

Camshaft drive belt slipped or stripped.
Was a problem found?
- Verify repair Go to Step 23
23
1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no malfunctions
have been found, review/inspect the following:

Visual/physical inspection.

Tech 2 data.

All electrical connections within a suspected circuit and/or
system.
Was a problem found?
- Verify repair Go to Step 24

6E-358 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
12
Check the fuel pressure. Refer to Fuel System
Diagnosis.
Was a problem found?
- Verify repair Go to Step 13
13
Monitor "B1S1 (Bank 1 Sensor 1) Status" and "B2S1
(Bank 2 Sensor 1) Status" on the Tech 2.
Is the "B1S1 (Bank 1 Sensor 1) Status" or "B2S1
(Bank 2 Sensor 1) Status" in the lean condition?
- Go to Step 14 Go to Step 15
14
Check items that can cause the engine to run lean.
Refer to DTC P0171 "O2 Sensor System Too Lean
(Bank 1)" or DTC P0174 "O2 Sensor System Tool
Lean (Bank 2)".
Was a problem found?
- Verify repair Go to Step 15
15
Check spark plugs for proper heat range.
Were incorrect spark plugs installed?
- Verify repair Go to Step 16
16
1. Remove excessive carbon buildup with a top
engine cleaner.
2. Re-evaluate vehicle performance.
Is detonation still present?
- Verify repair Go to Step 17
17
Check for an engine mechanical problem. Perform a
cylinder compression check. Refer to Engine
Mechanical.
Was a problem found?
- Verify repair Go to Step 18
18
1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection.

Tech 2 data.

All electrical connections within a suspected circuit
and/or system.
Was a problem found?
- Verify repair Go to Step 19
19
Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the "SPS (Service Programming System)".
Was the problem solved?
- Verify repair Go to Step 20
20
Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. Following
ECM programming, the immobilizer system (if
equipped) must be linked to the ECM. Refer to section
11 “Immobilizer System-ECM replacement” for the
ECM/Immobilizer linking procedure.
- Verify repair -

6E-360 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Step Action Value (s) Yes No
11
1. Using a Tech 2, display the ECT sensor and IAT
sensor value.
2. Check the specified value or wire.
Was the problem found?
- Verify repair Go to Step 12
12
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 13
13
Check for proper calibration of the speedometer.
Does the speed indicated on the speed meter closely
match the vehicle speed displayed on the Tech 2?
- Go to Step 15 Go to Step 14
14
Diagnose and repair the inaccurate speedometer
condition as necessary. Refer to Vehicle Speed
Sensor in Electrical Diagnosis.
- Verify repair -
15
Check for proper calibration of the fuel gauge.
Was a problem found?
- Verify repair Go to Step 16
16
Check for the following engine mechanical problems
(refer to Engine Mechanical):

Low compression.

Worn camshaft.

Sticking or leaking valves.

Valve timing.
Was a problem found?
- Verify repair Go to Step 17
17
1. Review all diagnostic procedures within this table.
2. If all procedures have been completed and no
malfunctions have been found, review/inspect the
following:

Visual/physical inspection.

Tech 2 data.

All electrical connections within a suspected circuit
and/or system.
Was a problem found?
- Verify repair Go to Step 18
18
Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the "SPS (Service Programming System)".
Was the problem solved?
- Verify repair Go to Step 19

6E-366 3.5L ENGINE DRIVEABILITY AND EMISSIONS
BACKFIRE SYMPTOM
DEFINITIONS: Fuel ignites in the intake manifold, or in
the exhaust system, making a loud popping noise.



Step Action Value (s) Yes No
1
Was the "On-Board Diagnostic (OBD) System Check"
performed?
- Go to Step 2 Go 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 4 Go to Visual /
physical Check.
4
Check for proper ignition voltage output with the spark
tester.
Was a problem found?
- Verify repair Go to Step 5
5
Check the ignition coils for cracks or carbon tracking.
If a problem is found, repair as necessary.
Was a problem found?
- Verify repair Go to Step 6
6
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must
be determined before replacing the spark plugs.
Was a problem found?
- Verify repair Go to Step 7
7
Check the fuel pressure. Refer to Fuel System
Pressure Test.
Was a problem found?
- Verify repair Go to Step 8
8
Refer to 6E-116 page Fuel System Diagnosis to
determine if there is a problem with fuel delivery.
Was a problem found?
- Verify repair Go to Step 9
9
Check the CKP sensor signal, shield wire, or
installation condition. Refer to DTC P0336 "Crankshaft
Position Sensor Circuit Range/Performance" and DTC
P0337 "Crankshaft Position Sensor Circuit No Signal".
Was a problem found?
- Verify repair Go to Step 10