2004 ISUZU TF SERIES fuel type

ENGINE DRIVEABILITY AND EMISSIONS 6E–159
DIAGNOSTIC TROUBLE CODE (DTC) P0134 O2 SENSOR NO ACTIVITY
DEFECTED (BANK 1 SENSOR 1)
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) supplies a bias
voltage of about 450 mV between the heated ox ygen
sensor (HO2S) high and low circuits. The ox ygen
sensor varies the voltage within a range of about 1000
mV when the ex haust is rich, down through about 10
mV when ex haust is lean. The ECM constantly monitors
the HO2S signal during “Closed Loop” operation andcompensates for a rich or lean condition by decreasing
or increasing injector pulse width as necessary. If the
Bank 1 HO2S 1 voltage remains at or near the 450 mV
bias for an ex tended period of time, Diagnostic Trouble
Code P0134 will be set, indicating an open sensor
signal or sensor low circuit.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0134 A O
2 Sensor Circuit No Activity Detecte d
(Ba nk 1 Se nsor 1)1. No DTC re la ting to MAP sensor, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. Engine coolant temperature is more than
60 de g.C.
3. Engine run time is longer than 40 seconds.
4. Ma ss a ir flo w is mo re tha n 7g/s.
5. O
2 se nsor ba nk 1 output vo lta ge is
between 300mV and 600mV.“Ope n Lo op” fuel control.

ENGINE DRIVEABILITY AND EMISSIONS 6E–163
DIAGNOSTIC TROUBLE CODE (DTC) P0135 O2 SENSOR HEATER CIRCUIT
(BANK 1 SENSOR 1)
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
Heated ox ygen sensors are used to minimize the
amount of time required for “Closed Loop” fuel control
operation and to allow accurate catalyst monitoring. The
ox ygen sensor heater greatly decreases the amount of
time required for fuel control sensors Bank 1 HO2S 1 1
to become active. Ox ygen sensor heaters are required
by catalyst monitor sensors Bank 1 HO2S 2 to maintain
a sufficiently high temperature which allows accurate
ex haust ox ygen content readings further from theengine.
The engine control module (ECM) will run the heater
test only after a cold start (determined by engine coolant
and intake air temperature at the time of start-up) and
only once during an ignition cycle. When the engine is
started the ECM will monitor the HO2S voltage. When
the HO2S voltage indicates a sufficiently active sensor,
the ECM looks at how much time has elapsed since
start-up. If the ECM determines that too much time was
required for the Bank 1 HO2S 1 to become active, a
Diagnostic Trouble Code P0135 will set.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0135 A O
2 Se nsorHea ter Circuit (Bank 1 Sen-
sor 1)1. No DTC re lating to MAP senso r a nd ECT
se nsor.
2. Engine coolant temperature is more than
60 de g. C.
3. Engine run time is longer than 20 seconds.
4. MAP se nso r o utput is mo re tha n 70kPa .
5. O
2 se nsor ba nk 1 hea te r current mo re tha n
10mA.No fail-safe function.

ENGINE DRIVEABILITY AND EMISSIONS 6E–211
DIAGNOSTIC TROUBLE CODE (DTC) P1167 FUEL SUPPLY SYSTEM RICH
DURING DECELERATION FUEL CUT OFF
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during deceleration (fuel cut
off). The ECM monitors the voltage of the ox ygen
sensor during fuel cut off. When a fuel cut off mode of
operation is requested during “Closed Loop” operation
(by deceleration), the ECM will provide more fuel to the
engine. Under these conditions the ECM should detect
a “lean” condition (low ox ygen sensor voltage). If this“lean” ex haust is not detected at this time, a Diagnostic
Trouble Code P1167 will set.
Diagnostic Aids
Check the following items:
Fuel pressure - The system will go rich if pressure is
too high. The ECM can compensate for some
increase. However, if fuel pressure is too high, a
Diagnostic Trouble Code P1167 may be set. Refer to
Fuel System Diagnosis.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1167 D Fuel Supply Sy stem Rich During
De ce le ration Fue l Cuto ff1. No DTC re lating to MAP senso r, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. O
2 se nsor ba nk 1 output vo lta ge is mo re
than 550mV in deceleration fuel cutoff
mo de .No fail-safe function.

6E–214 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P1171 FUEL SUPPLY SYSTEM LEAN
DURING POWER ENRICHMENT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine control module (ECM) internal circuitry can
identify if the vehicle fuel system is capable of supplying
adequate amounts of fuel during heavy acceleration
(power enrichment). The ECM monitors the voltage of
the ox ygen sensor during power enrichment. When a
power enrichment mode of operation is requested
during “Closed Loop” operation (by heavy acceleration),the ECM will provide more fuel to the engine. Under
these conditions the ECM should detect a “rich”
condition (high ox ygen sensor voltage). If this “rich”
ex haust is not detected at this time, a Diagnostic
Trouble Code P1171 will set. A plugged fuel filter or
restricted fuel line can prevent adequate amounts of fuel
from being supplied during power enrichment mode.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P1171 D Fuel Supply System Lean During
Po wer Enrichment 1. No DTC re lating to MAP senso r, TPS,
EVAP purge, ECT sensor, CKP sensor,
VSS, injecto r contro l circuit and ignitio n
co ntro l circuit.
2. Engine coolant temperature is more than
60 de g. C.
3. Ma ss a ir flo w is below 13.5m/s.
4. O
2 sensor bank 1 output voltage is below
350mV in power enrichment mode. No fail-safe function.

6E–258 ENGINE DRIVEABILITY AND EMISSIONS
EXCESSIVE EXHAUST EMISSIONS OR ODORS SYMPTOM
DEFINITIONS: Vehicle fails an emission test. There is ex cessive “rotten egg” smell. (Ex cessive odors do not
necessarily indicate ex cessive emissions.)
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?—Go to Step 2Go to 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 visual/physical check performed?
—Go to Step 4Go to Visual /
physical Check.
4 Does the customer continual accelerate On/Off during
cold condition?—System OK Go to Step 5
5 Is the customer using the incorrect fuel type?
—Replace with
unleaded fuel Go to Step 6
6 Check for vacuum leaks (vacuum lines, intake
manifold, throttle body, etc.)
Were any vacuum leaks found?—Go to Step 17Go to Step 7
7 1. Check fuel cap for proper installation.
2. Secure the fuel cap if necessary.
Was a problem found?—Go to Step 17Go to Step 8
8 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis” .
Was a problem found?—Go to Step 17Go to Step 9
9 1. Check for faulty, plugged or incorrectly installed
PCV valve.
2. Verify that the PCV system is not plugged.
Was a problem found? —Go to Step 17Go to Step 10
10 Check the injector connectors, if any of the injectors
are connected to an incorrect cylinder, correct as
necessary.
Was a problem found?—Go to Step 17Go to Step 11
11 Perform the
Injector Coil/Balance Test
(Refer to 6E-
98 page).
Was a problem found.—Go to Step 17Go to Step 12
12 Check for a problem with the engine cooling system.
Was a problem found?—Go to Step 17Go to Step 13
13 Check EVAP canister for fuel loading. Refer to
Evaporative Emission Control System.
Was a problem found?—Go to Step 17Go to Step 14
14 Check the EVAP purge solenoid valve operation.
Is the valve operated normally?—Go to Step 17Veri fy repai r &
Go to Step 15
15 Check the ex haust system for a possible restriction:
Damaged or collapsed pipes
Internal catalytic converter failure
Was a problem found?—Verify repair &
Go to Step 16Go to Step 17

6E–272 ENGINE DRIVEABILITY AND EMISSIONS
FUEL INJECTOR
Removal Procedure
NOTE: If the fuel injectors are leaking, the engine oil
may be contaminated with fuel. Check the oil for signs
of contamination and change the oil and filter if
necessary.
NOTE: Use care in removing the fuel injector in order to
prevent damage to the fuel injector al connector pins or
fuel injector nozzles. The fuel injector is an al
component and should not be immersed in any type of
cleaner as this may damage the fuel injector.
Important: Fuel injectors are serviced as complete
assembly only.
1. Disconnect the negative battery cable.
2. Disconnect al connector from fuel injector.
3. Remove the fuel rail. Refer to Fuel Rail Removal
Procedure.
4. Remove the fuel injector retainer clip.
5. Remove the fuel injector assembly from fuel rail.
6. Remove O-ring from the fuel injector.
7. Remove O-ring backup from fuel injector.Inspection
1. Inspect O-ring for crack, damage or leaks.
2. Replace worn or damaged O-ring.
3. Lubricate the new O-rings with engine oil before
installation.
Installation Procedure
1. Lubricate the new O-ring with engine oil.
2. Install the O-ring backup on the fuel injector.
3. Install new O-ring on the fuel injector.
4. Install all four injector on the fuel rail.
5. Use new injector retainer clip to retain the injetor to
the fuel rail.
6. Coat the end of the fuel injector with engine oil.

6E–276 ENGINE DRIVEABILITY AND EMISSIONS
Oil in the combustion chamber.
The spark plug gap is not set correctly.
If spark plug fouling is ex cessive, check the fuel and al
system for possible causes of trouble. If fuel and al
system are normal, install spark plugs of a higher heat
range which have the same physical dimensions as the
original equipment spark plugs.
The following symptoms are characteristics of spark
plugs that are running too hot:
Fuel mixture is too lean.
Heat range is incorrect.
If vehicle usage does not conform to normal driving
conditions, a more suitable spark plug may be
substituted.
If fuel and al system are normal, in most cases of this
sort, the problem can be corrected by using a colder
type spark plug with the same physical dimensions as
the original equipment spark plug.
3. Check the gaskets for damage and replace if
necessary.
4. Measure the spark plug gap. The specification is 1.0
to 1.1mm (0.039 to 0.043").
5. Adjust the spark gap by bending the grounded
electrode.Installation
1. Tighten the spark plug to the 25N·m (2.5kgf·m).
2. Push the spark plug cable in until it snaps in.
Installation Procedure
1. Install the spark plug to the cylinder head.
2. Tighten the spark plug with specified tightening
torque.
Tightening Torque
Bolt: 25N·m (2.5kgf·m)
3. Connect the spark plug cable to the spark plug.
4. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify proper connection of spark plug cables for each
cylinders.

ENGINE EXHAUST 6F-3





























When inspecting or replacing exhaust system components,
make sure there is adequate clearance from all points on the
underbody to prevent overheating the floor pan and possible
damage to the passenger compartment insulation and trim
materials.
Check complete exhaust system and nearby body areas and
rear compartment lid for broken, damaged, missing or
mispositioned parts, open seams, holes, loose connections or
other deterioration which could permit exhaust fumes to seep
into the rear compartment or passenger compartment. Dust or
water in the rear compartment may be an indication of a
problem in one of these areas. Any faulty areas should be
corrected immediately.
Hangers
Various types of hangers are used to support exhaust
system(s). These include conventional rubber straps, rubber
rings, and rubber blocks.
The installation of exhaust system supports is very important,
as improperly installed supports can cause annoying vibrations
which can be difficult to diagnose.
Three Way Catalytic Converter (If applicable)
The three way catalytic converter is an emission control device
added to the exhaust system to reduce pollutants from the
exhaust gas stream.

CAUTION: The catalytic converter requires the use of
unleaded fuel only.
Periodic maintenance of the exhaust system is not required. If
the vehicle is raised for other service, it is advisable to check
the condition of the complete exhaust system.
A dual bed monolith catalytic converter is used in combination
with three way catalytic converter.
Catalytic Types:
Three way (Reduction/Oxidation) catalyst
The catalyst coating on the three way (reduction) converter
contains platinum and rhodium which lowers the levels of
nitrous oxide (NOx) as well as hydrocarbons (HC) and carbon
monoxide (Co).
Gasket
The gasket must be replaced whenever a new exhaust pipe,
muffler or catalytic converter is installed.