fuel ISUZU TF SERIES 2004 Workshop Manual

ENGINE DRIVEABILITY AND EMISSIONS 6E–5
ENGINE CRANKS BUT WILL NOT RUN ..... 6E-233
HARD START SYMPTOM ............................ 6E-236
ROUGH, UNSTABLE, OR INCORRECT IDLE,
STALLING SYMPTOM ............................... 6E-239
SURGES AND/OR CHUGS SYMPTOM ...... 6E-242
HESITATION, SAG, STUMBLE SYMPTOM 6E-245
CUTS OUT, MISSES SYMPTOM ................. 6E-248
LACK OF POWER, SLUGGISH OR SPONGY
SYMPTOM ................................................. 6E-251
DETONATION/SPARK KNOCK SYMPTOM 6E-254
POOR FUEL ECONOMY SYMPTOM .......... 6E-256
EXCESSIVE EXHAUST EMISSIONS OR
ODORS SYMPTOM ................................... 6E-258
DIESELING, RUN-ON SYMPTOM ............... 6E-261
BACKFIRE SYMPTOM ................................. 6E-262
ON-VEHICLE SERVICE PROCEDURE ....... 6E-264
ENGINE CONTROL MODULE (ECM) .......... 6E-264
CRANKSHAFT POSITION (CKP) SENSOR 6E-264
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR .................................................... 6E-265
INTAKE AIR TEMPERATURE (IAT) SENSOR 6E-265
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR .................................................... 6E-266
THROTTLE POSITION SENSOR (TPS) ...... 6E-266
IDLE AIR CONTROL (IAC) VALVE .............. 6E-267
KNOCK SENSOR ......................................... 6E-268
POWER STEERING PRESSURE (PSP)
SWITCH ..................................................... 6E-268
HEATED OXYGEN SENSOR (HO2S) ......... 6E-269
EVAP CANISTER PURGE VALVE SOLENOID 6E-269
FUEL PRESSURE RELIEF .......................... 6E-270
FUEL RAIL ASSEMBLY ............................... 6E-270
FUEL INJECTOR .......................................... 6E-271
FUEL PRESSURE REGULATOR ................ 6E-273
IGNITION COIL ............................................ 6E-275
SPARK PLUGS ............................................ 6E-275
SPARK PLUG CABLES ................................ 6E-277
EMISSION CONTROL ; CO ADJUSTER (W/O
CATALYSTIC CONVERTER) .................. 6E-277
SPECIAL SERVICE TOOLS ......................... 6E-279

6E–6 ENGINE DRIVEABILITY AND EMISSIONS
ABBREVIATIONS CHARTS
A bbreviations A ppellation
A/C Air Conditioner
A/T Automatic Transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CEL Check Engine Lamp
CKP Crankshaft Position
DLC Data Link Connector
DTC Diagnostic Trouble Code
DVM Digital Volt Meter
ECM Engine Control Module
ECT Engine Coolant Temperature
EEPROM Electrically Erasable & Programmable Read Only Memory
EVAP Evaporative Emission
EVRV Electric Vacuum Regulating Valve
EXH Exhaust
FT Fuel Temperature
GND Ground
GRY Gray
HOS2 Heated Ox ygen Sensor
IAC Idel Air Control
IAT Intake Air Temperature
IG Ignition
ITP Intake Throttle Position
KS Knock Sensor
M/T Manual Transmission
MAP Manifold Absolute Pressure
MIL Malfunction Indicator Lamp
OBD On-Board Diagnostic
ORN Orange
OT Oil Temperature
PNK Pink
RED Red
SW Switch
TB Throttle Body
TEMP Temperature
TP Throttle Posi tion
VCC Voltage Constant Control
VSS Vehicle Speed Sensor
WHT Whi te
Y EL Yellow

6E–10 ENGINE DRIVEABILITY AND EMISSIONS
(1) Canister(1)
(2)Fuel Tank
Fuel Pump
2 1
(1)
(2)Vehicle Speed Sensor (VSS)
Transmission Assembly
12
(1)
(2)Power Steering Pressure Switch
Power Steering Oil Pump Assembly
12

6E–28 ENGINE DRIVEABILITY AND EMISSIONS
CONNECTOR LIST
No. Connector face No. Connector face
B-24
Green Meter-BC-122
CO Adjuster
B-58
Black Check connectorE-6
Fuel injector
B-62
White Ignition switch (IGSUB : G1)E-7
Fuel injector
B-63
White Ignition switch (IGSUB : G2)E-8
Fuel injector
B-68
ImmobilizerE-9
Fuel injector
C-2
Silver Engine room-RH groundE-18
Ignition coil
C-56
ECME-60
ECM
C-107
White J/B E2E-72
Engine earth-A
C-108
White J/B E1E-74
Engine earth-B
C-121
IAT sensorE-77
O
2 sensor

ENGINE DRIVEABILITY AND EMISSIONS 6E–29
No. Connector face No. Connector face
E-84
Knock sensorP-1
Silver Battery (+)
E-85
MAP sensorP-2
Silver Relay & Fuse box
F-2
White Fuel pump & sensorP-5
Silver Battery (-)
H-4
White Engine room ~ MissionP-6
Silver Body earth (Ground)
H-6
White Engine room ~ INSTP-10
Silver Engine ground
H-7
White Engine room ~ INSTX-2
Black Relay; Fuel pump
H-9
Blue Engine room ~ ChassisX-11
Black Relay; Heater
H-18
White Engine room ~ INSTX-14
Black Relay; A/C Compressor
H-31
Engine room ~ Mission
H-34
Engine ~ Engine room

ENGINE DRIVEABILITY AND EMISSIONS 6E–31
RELAY A ND FUSE BOX LOCATION (LHD & RHD)
RELAY & FUSE BOX
RELAY
No. Relay Name
X-1 RELAY; TAIL LIGHT
X-2 RELAY; FUEL PUMP
X-3 RELAY; HORN
X-4 RELAY; DIMMER
X-5 RELAY; FRT FOG
LIGHT (LHD only)
X-6 RELAY; STARTER
X-7 RELAY; COND, FAN
X-8—
X-9—
X-10—
X-11 RELAY; HEATER
X-12 RELAY; HEAD LIGHT
X-13—
X-14 RELAY; A/C COMP
X-15 RELAY; THERMO
FUSE
NO. Fuse Name
EB-1 15A ECM
EB-2—
EB-3 15A FRT FOG
EB-4 15A ACG (S)
EB-5 10A ILLUMI
EB-6 10A TAIL
EB-7 10A H/LIGHT-RH
10A H/LIGHT-RH-LOW
EB-8 10A H/LIGHT-LH
10A H/LIGHT-LH-LOW
(LHD only)
EB-9 20A FUEL PUMP
EB-10 10A O
2 SENSOR
EB-11 10A H/LIGHT-RH-
HIGH (LHD only)
EB-12 10A H/LIGHT-LH-
HIGH (LHD only)
EB-13 10A A/C
EB-14—
EB-15 10A HORN
EB-16 10A HAZARD
SLOW BLOW FUSE
NO. Slow Blow Fuse Name FUSE NO. Slow Blow Fuse Name
SBF-1 100A MAIN SBF-6—
SBF-2—SBF-7—
SBF-3—SBF-8 30A BLOWER
SBF-4 20A COND, FAN SBF-9 50A IG 2
SBF-5 40A IG 1

6E–44 ENGINE DRIVEABILITY AND EMISSIONS
Connector J2 Port: View Looking Into ECM Case
1
1716
32
PIN32
PIN1 PIN17
PIN16
Pin
No. B/
Box
No.Pin FunctionWire
ColorSignal or Continuity
ECM
ConnectionTester Position
Key SW
OffKey SW
OnEngine
IdleEngine
2000rpmRange (+) (-)
J2-1 J2-1 Inta ke Air Temp. (IAT)
Sensor GroundGRN Continuity
with
ground- - - Disconnect
J2-1 GND
J2-2 J2-2 Batte ry Powe r Supply RED/
WH T10-14V Co nnect DC V J2-2 GND
J2-3 J2-3 Ignitio n Powe r Supply BLU/
YELLess than
1V10-14V Connect DC V J2-3 GND
J2-4 J2-4 To Da ta Link
Conne ctor No. 6BLU - - - - - - - -
J2-5 J2-5 No Connection - - - - - - - - -
J2-6 J2-6 Oxy ge n Se nsor
(Ground)PNK Continuity
with
ground- - - Connect
J2-6 GND
J2-7 J2-7 No Connection - - - - - - - - -
J2-8 J2-8 No Connection - - - - - - - - -
J2-9 J2-9 No Connection - - - - - - - - -
J2-10 J2-10 CO Adjust Signa l
(W/O Cata ly stic
Converter)YEL - - - - - - - -
J2-11 J2-11 Fuel Pump Re la y GRN/
WH T10-14V
While relay
is activated;
10-14V
R elay is no t
activated;
Less than
1V10-14V Connect DC V J2-11 GND
J2-12 J2-12 No Connection - - - - - - - - -
J2-13 J2-13 A/C Compre sso r
RelayGRY/
REDLess than
1VA/C comp. is operated: Less than 1V
A/C comp. is not operated: 10-14VCo nnect DC V J2-13 GND
J2-14 J2-14 No Connection - - - - - - - - -
J2-15 J2-15 No Connection - - - - - - - - -
J2-16 J2-16 No Connection - - - - - - - - -
J2-17 J2-17 CO Adjust (W/O
Cata ly stic Conv erter)RED - - - - - - - -
J2-18 J2-18 Batte ry Powe r Supply RED/
WH T10-14V Co nnect DC V J2-18 GND
J2-19 J2-19 No Connection - - - - - - - - -
J2-20 J2-20 Pow er Ste ering
Pressure SwitchGRN/
YELLess than
1V
Pressure switch is turned on: Less than 1V
Pressure switch is turned off: 10-14VCo nnect DC V J2-20 GND
J2-21 J2-21 Oxygen Sensor BLU Less than
1VApprox .
0.4VWave form D or 0.1 -
0.9V Co nnect DC V J2-21 J2-6
J2-22 J2-22 Inta ke Air Temp. (IAT)
Sensor (Signa l)YEL/
GRNLess than
1V
20
: Approx. 2.9V / 40
: Approx . 1.8V V
/ 60
: Approx. 1.1V / 80
: Approx . 0.6VCo nnect DC V J2-22 33

6E–48 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)
The engine control module (ECM) is located on the
intake manifold. The ECM controls the following.
Fuel metering system
Ignition timing
On-board diagnostics for electrical functions.
The ECM constantly observes the information from vari-
ous sensors. The ECM controls the systems that affect
vehicle performance. And it performs the diagnostic
function of the system.
The function can recognize operational problems, and
warn to the driver through the check engine lamp, and
store diagnostic trouble code (DTC). DTCs identify the
problem areas to aid the technician in marking repairs.
The input / output devices in the ECM include analog to
digital converts, signal buffers, counters and drivers.
The ECM controls most components with electronic
switches which complete a ground circuit when turned
on.
Inputs (Operating condition read):
Battery voltage
Electrical ignition
Ex haust oxygen content
Intake manifold pressure
Intake air temperature
Engine coolant temperature
Crankshaft positionKnock signal
Throttle position
Vehicle speed
Power steering pressure
Air conditioning request on or off
Outputs (Systems controlled):
Ignition control
Fuel control
Idle air control
Fuel pump
EVAP canister purge
Air conditioning
Diagnostics functions
Manifold Absolute Pressure (MAP) Sensor
The MAP sensor is a strain gage. A pressure strains the
resistance on the silicon base. At that time the
resistance value changes. And it changes voltage. In
other words it measures a pressure value. It is installed
to the intake manifold. Output voltage of the MAP
sensor is low as pressure is low. (1) J1 Port
(2) J2 Port
12
C h arac teris tic of MA P S ens or -R ef erenc e-
0 0.51 1.52 2.53 3.54 4.55
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Mani fold A bs olute P res s ure (K P a) (T ec h2 Reading)
Output Voltage (V)

ENGINE DRIVEABILITY AND EMISSIONS 6E–49
Throttle Position Sensor (TPS)
The TPS is a potentiometer connected to throttle shaft
on the throttle body.
The engine control module (ECM) monitors the voltage
on the signal line and calculates throttle position. As the
throttle valve angle is changed when accelerator pedal
moved. The TPS signal also changed at a moved
throttle valve. As the throttle valve opens, the output
increases so that the output voltage should be high.
The throttle body has a throttle plate to control the
amount of the air delivered to the engine.
Engine coolant is directed through a coolant cavity in
the throttle body to warm the throttle valve and to
prevent icing.
Idle Air Control (IAC) Valve
The idle air control valve (IAC) valve is two directional
and gives 2-way control. With power supply to the coils
controlled steps by the engine control module (ECM),
the IAC valve's pintle is moved to adjust idle speed,
raising it for fast idle when cold or there is ex tra load
from the air conditioning or power steering.
By moving the pintle in (to decrease air flow) or out (to
increase air flow), a controlled amount of the air can
move around the throttle plate. If the engine speed is
too low, the engine control module (ECM) will retract the
IAC pintle, resulting in more air moving past the throttle
plate to increase the engine speed.
If the engine speed is too high, the engine control
module (ECM) will ex tend the IAC pintle, allowing less
air to move past the throttle plate, decreasing the
engine speed.
The IAC pintle valve moves in small step called counts.
During idle, the proper position of the IAC pintle is
calculated by the engine control module (ECM) based
on battery voltage, coolant temperature, engine load,
and engine speed.
If the engine speed drops below a specified value, and
the throttle plate is closed, the engine control module
(ECM) senses a near-stall condition. The engine control
module (ECM) will then calculate a new IAC pintle valve
position to prevent stalls.
If the IAC valve is disconnected and reconnected with
the engine running, the idle speed will be wrong. In this
case, the IAC must be reset. The IAC resets when the
key is cycled “On” then “Off”. When servicing the IAC, it
should only be disconnected or connected with the
ignition “Off”.
The position of the IAC pintle valve affects engine start-
up and the idle characteristic of the vehicle.
If the IAC pintle is fully open, too much air will be
allowed into the manifold. This results in high idle
speed, along with possible hard starting and lean air/
fuel ratio. (1) Throttle Position Sensor
(2) Idle Air Control (IAC) Valve
1
2
C haract erist ic of TPS -R ef erenc e-
0 0. 51 1. 52 2. 53 3. 54 4. 55
0 102030405060708090100
Th rot t le An gle ( % ) ( Tec h 2 R ea di n g)
Output Voltage (V)
StepCoilAB CDCoil A High
(EC M J1-28)On On
Coil A Low
(EC M J1-30)On On
Coil B High
(EC M J1-13)On On
Coil B Low
(EC M J1-29)On On

(IAC Valve Close Direction)
(IAC Valve Open Direction)

ENGINE DRIVEABILITY AND EMISSIONS 6E–51
Intake Air Temperature (IAT) Sensor
The IAT sensor is a thermistor. A temperature changes
the resistance value. And it changes voltage. In other
words it measures a temperature value. Low air
temperature produces a high resistance.
The ECM supplies 5 volts signal to the IAT sensor
through resisters in the ECM and measures the voltage.
The signal voltage will be high when the air temperature
is cold, and it will be low when the air temperature is
hot.
Vehicle Speed Sensor (VSS)
The VSS is a magnet rotated by the transmission output
shaft. The VSS uses a hall element. It interacts with the
magnetic field treated by the rotating magnet. It outputs
pulse signal. The 12 volts operating supply from the
meter fuse.
Heated Oxygen (O2) Sensor
The heated ox ygen sensor consists of a 4-wire low
temperature activated zirconia ox ygen analyzer element
with heater for operating temperature of 315°C, and
there is one mounted on each ex haust pipe.
A constant 450millivolt is supplied by the ECM between
the two supply terminals, and oxygen concentration in
the ex haust gas is reported to the ECM as returned
signal voltage.
The ox ygen present in the ex haust gas reacts with the
sensor to produce a voltage output. This voltage should
constantly fluctuate from approx imately 100mV to
1000mV and the ECM calculates the pulse width
commanded for the injectors to produce the proper
combustion chamber mix ture.
Low ox ygen sensor output voltage is a lean mix ture
which will result in a rich commanded to compensate.
High ox ygen sensor output voltage is a rich mix ture
which result in a lean commanded to compensate.
When the engine is first started the system is in “Open
Loop” operation. In “Open Loop”, the ECM ignores the
signal from the ox ygen sensors. When various
conditions (ECT, time from start, engine speed &
ox ygen sensor output) are met, the system enters
“Closed Loop” operation. In “Closed Loop”, the ECM
calculates the air fuel ratio based on the signal from the
ox ygen sensors.
Heated ox ygen sensors are used to minimize the
amount of time required for closed loop fuel control to
begin operation and allow accurate catalyst monitoring.
The ox ygen sensor heater greatly decreases the
amount of time required for fuel control sensors to
become active.
Oxygen sensor heaters are required by catalyst monitor
and sensors to maintain a sufficiently high temperature
which allows accurate ex haust ox ygen content readings
further away from the engine.
C haract erist ic of I A T Sen sor -Ref erence-
10 100 1000 10000 100000
- 20 - 10 0 10 20 30 40 50 60 70 80 90 100 110 120
I nt ake A i r T emp. ( deg . C ) ( Tec h2 R eadi ng )
Resistance (ohm) (Solid Line)