2004 ISUZU TF SERIES fuel pump

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-47
Signal or Continuity Tester Position Pin
No. B/Box
No. Pin Function Wire
Color
Key SW Off Key SW On Engine IdleEngine
2000rpm ECM
Connection Range (+) (-)
B16 B16 Idle Air Control
(IAC) Valve
Coil A Low BLU/
RED Less than 1V Less than 1V / 10-14V Connect DC V B16 GND
B17 B17 Idle Air Control
(IAC) Valve
Coil B Low BLU/
BLKLess than 1V Less than 1V / 10-14V Connect DC V B17 GND
B18 B18 Check Engine
Lamp
(Immobilizer
Control Unit
Terminal B7) BRN/
YELLess than 1V Less than 1VLamp is turned on:
Less than 1V
Lamp is turned off: 10-14VConnect DC V B18 GND
B19 B19 Fuel Pump
Relay GRN/
WHT Less than 1V While relay is
activated:
10-14V
Relay is not
activated:
Less than 1V10-14V Connect DC V B19 GND
B20 B20 Mass Air Flow
(MAF) Sensor BLK/
YELLess than 1V Approx. 0.47VApprox. 1.5V
at 750 rpmApprox. 2V Connect DC V B20 GND
B21 B21 Bank 1 Oxygen
Sensor Signal PNK Less than 1V Approx. 0.4V 0.1 - 0.9V Connect DC V B21 B22
B22 B22 Bank 1 Oxygen
Sensor Ground BLU/
YELContinuity
with ground - - - Connect Ohm B22 GND
B23 B23 Bank 2 Oxygen
Sensor Signal RED Less than 1V Approx. 0.4V 0.1 - 0.9V Connect DC V B23 B24
B24 B24 Bank 2 Oxygen
Sensor Ground BLU/
BLKContinuity
with ground - - - Connect Ohm B24 GND
B25 B25 To Data Link
Connector
No.6 BLK/
GRN - - - - - - - -
B26 B26 Throttle
Position
Sensor (TPS)
Signal BLU Less than 1V Approx. 0.5V Approx. 0.6V Connect DC V B26 B39
B27 B27 TPS & Cam
Position
Sensor +5V
Supply GRN Less than 1V Approx. 5V Connect DC V B27 B39
B28 B28 Camshaft
Position (CMP)
Sensor Signal BLU - - Wave form - - - -
B29 B29 Inhibitor Switch
(AT Only) BLK Less than 1V P or N range: Less than 1V
Other than P or N range: 10-14V Connect DC V B29 GND
B30 B30 Power Steering
Pressure
Switch GRN/
YELLess than 1V Pressure switch is turned on: Less than 1V
Pressure Switch is turned off: 10-14V Connect DC V B30 GND
B31 B31 A/C Thermo
Relay GRN/
BLKLess than 1V A/C request is activated: 10-14V
A/C request is not activated: Less than 1VConnect DC V B31 GND

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-51

GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)


1 2
(1) A Port
(2) B Port


The engine control module (ECM) is located on the
common chamber. The ECM controls the following.

Fuel metering system

Ignition timing

On-board diagnostics for powertrain functions.

The ECM constantly observes the information from
various sensors. The ECM controls the systems tha
t
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

Exhaust oxygen content

Mass air flow

Intake air temperature

Engine coolant temperature

Crankshaft position

Camshaft position

Throttle position

Vehicle speed

Power steering pressure

Air conditioning request on or off

EGR valve position

Outputs (Systems controlled):

Ignition control

Fuel control

Idle air control

Fuel pump

EVAP canister purge

Air conditioning

Diagnostics functions

The vehicle with automatic transmission, the
interchange of data between the engine control module
(ECM) and the transmission control module (TCM) is
performed via a CAN-bus system.
The following signals are exchanged via the CAN-bus:

ECM to TCM:

ECM CAN signal status

Engine torque

Coolant temperature

Throttle position

Engine speed

A/C status

CAN valid counter

TCM to ECM:

Ignition timing retard request

Garage shift status

CAN valid counter

6E-56 3.5L ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR FUEL
METERING
The fuel metering system starts with the fuel in the fuel
tank. An electric fuel pump, located in the fuel tank,
pumps fuel to the fuel rail through an in-line fuel filter.
The pump is designed to provide fuel at a pressure
above the pressure needed by the injectors.
A fuel pressure regulator in the fuel rail keeps fuel
available to the fuel injectors at a constant pressure.
A return line delivers unused fuel back to the fuel tank.

The basic function of the air/fuel metering system is to
control the air/fuel delivery to the engine. Fuel is
delivered to the engine by individual fuel injectors
mounted in the intake manifold.
The main control sensor is the heated oxygen senso
r
located in the exhaust system. The heated oxygen
sensor reports to the ECM how much oxygen is in the
exhaust gas. The ECM changes the air/fuel ratio to the
engine by controlling the amount of time that fuel
injector is "On".
The best mixture to minimize exhaust emissions is 14.7
parts of air to 1 part of gasoline by weight, which allows
the catalytic converter to operate most efficiently.
Because of the constant measuring and adjusting of the
air/fuel ratio, the fuel injection system is called a "closed
loop" system.
The ECM monitors signals from several sensors in
order to determine the fuel needs of the engine. Fuel is
delivered under one of several conditions called
"mode". All modes are controlled by the ECM.

Acceleration Mode
The ECM provides extra fuel when it detects a rapid
increase in the throttle position and the air flow.

Battery Voltage Correction Mode
When battery voltage is low, the ECM will compensate
for the weak spark by increasing the following:

The amount of fuel delivered.

The idle RPM.

Ignition dwell time.

Clear Flood Mode
Clear a flooded engine by pushing the accelerator pedal
down all the way. The ECM then de-energizes the fuel
injectors. The ECM holds the fuel injectors de-
energized as long as the throttle remains above 80%
and the engine speed is below 800 RPM. If the throttle
position becomes less than 80%, the ECM again begins
to pulse the injectors "ON" and "OFF," allowing fuel into
the cylinders.

Deceleration Mode
The ECM reduces the amount of fuel injected when i
t
detects a decrease in the throttle position and the air
flow. When deceleration is very fast, the ECM may cu
t
off fuel completely for short periods.
Engine Speed/Vehicle Speed/Fuel Disable Mode
The ECM monitors engine speed. It turns off the fuel
injectors when the engine speed increase above 6400
RPM. The fuel injectors are turned back on when
engine speed decreases below 6150 RPM.

Fuel Cutoff Mode
No fuel is delivered by the fuel injectors when the
ignition is "OFF." This prevents engine run-on. In
addition, the ECM suspends fuel delivery if no reference
pulses are detected (engine not running) to preven
t
engine flooding.

Run Mode
The run mode has the following two conditions:

Open loop

Closed loop
When the engine is first started the system is in "open
loop" operation. In "open loop," the ECM ignores the
signal from the heated oxygen sensor (HO2S). I
t
calculates the air/fuel ratio based on inputs from the TP,
ECT, and MAF sensors.
The system remains in "open loop" until the following
conditions are met:

The HO2S has a varying voltage output showing
that it is hot enough to operate properly (this
depends on temperature).

The ECT has reached a specified temperature.


A specific amount of time has elapsed since
starting the engine.

Engine speed has been greater than a specified
RPM since start-up.
The specific values for the above conditions vary with
different engines and are stored in the programmable
read only memory (PROM). When these conditions are
met, the system enters "closed loop" operation. In
"closed loop," the ECM calculates the air/fuel ratio
(injector on-time) based on the signal from the HO2S.
This allows the air/fuel ratio to stay very close to 14.7:1.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-57
Starting Mode
When the ignition is first turned "ON," the ECM
energizes the fuel pump relay for two seconds to allo
w
the fuel pump to build up pressure. The ECM then
checks the engine coolant temperature (ECT) senso
r
and the throttle position sensor to determine the proper
air/fuel ratio for starting.
The ECM controls the amount of fuel delivered in the
starting mode by adjusting how long the fuel injectors
are energized by pulsing the injectors for very short
times.

Fuel Metering System Components
The fuel metering system is made up of the following
parts.

Fuel injector

Throttle Body

Fuel Rail

Fuel Pressure regulator

ECM

Crankshaft position (CKP) sensor

Camshaft position (CMP) sensor

Idle air control valve

Fuel pump

Fuel Injector
The sequential multi-port fuel injection fuel injector is a
solenoid operated device controlled by the ECM. The
ECM energizes the solenoid, which opens a valve to
allow fuel delivery.
The fuel is injected under pressure in a conical spray
pattern at the opening of the intake valve. Excess fuel
not used by the injectors passes through the fuel
pressure regulator before being returned to the fuel
tank.

Fuel Pressure Regulator
The fuel pressure regulator is a diaphragm-operated
relief valve mounted on the fuel rail with fuel pump
pressure on one side and manifold pressure on the
other side. The fuel pressure regulator maintains the
fuel pressure available to the injector at three times
barometric pressure adjusted for engine load. It may be
serviced separate.
If the pressure is too low, poor performance and a DTC
P0131, P0151, P0171, P0174, P1171 or P1174 will be
the result. If the pressure is too high, excessive odo
r
and/or a DTC P0132, P0152, P0172 or P0175 will be
the result. Refer to Fuel System Diagnosisfo
r
information on diagnosing fuel pressure conditions.
Fuel Rail
The fuel rail is mounted to the top of the engine and
distributes fuel to the individual injectors. Fuel is
delivered to the fuel inlet tube of the fuel rail by the fuel
lines. The fuel goes through the fuel rail to the fuel
pressure regulator. The fuel pressure regulato
r
maintains a constant fuel pressure at the injectors.
Remaining fuel is then returned to the fuel tank.







055RV009
Fuel Pump Electrical Circuit
When the key is first turned "ON," the ECM energizes
the fuel pump relay for two seconds to build up the fuel
pressure quickly. If the engine is not started within two
seconds, the ECM shuts the fuel pump off and waits
until the engine is cranked. When the engine is cranked
and the 58 X crankshaft position signal has been
detected by the ECM, the ECM supplies 12 volts to the
fuel pump relay to energize the electric in-tank fuel
pump.
An inoperative fuel pump will cause a "no-start"
condition. A fuel pump which does not provide enough
pressure will result in poor performance.

Camshaft Position (CMP) Sensor Signal
The ECM uses this signal to determine the position o
f
the number 1 piston during its power stroke, allowing
the ECM to calculate true sequential multiport fuel
injection. Loss of this signal will set a DTC P0341. If the
CMP signal is lost while the engine is running, the fuel
injection system will shift to a calculated sequential fuel
injection based on the last fuel injection pulse, and the
engine will continue to run. The engine can be restarted
and will run in the calculated sequential mode as long
as the fault is present, with a 1-in-6 chance of being
correct.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-61
GENERAL DESCRIPTION FOR
EVAPORATIVE EMISSION SYSTEM




3 1 2
(1) Purge Solenoid Valve
(2) From Canistor to Purge Solenoid
(3) From Purge Solenoid to Intake








1
2
(1) Canistor
(2) Air Separator


The basic evaporative emission control system used on
the charcoal canister storage method. The method
transfers fuel vapor from the fuel tank to an activated
carbon (charcoal) storage devise to hold the vapors
when the vehicle is not operating.
The canister is located on the rear axle housing by the
frame cross-member.
When the engine is running, the fuel vapor is purged
from the carbon element by intake air flow and
consumed in the normal combustion process.

EVAP Control System
The evaporate emission canister purge is controlled by
a duty solenoid valve that allows manifold to purge the
canister when following operating conditions are met.
Purge solenoid valve operating condition at idle
condition:

Engine speed is below 1000rpm.

Vehicle speed is below 3km/h.

Engine coolant temperature is more than 80C.

Intake air temperature is more than 10C.

In closed loop operation.
All above conditions are met for 4 seconds.

Purge solenoid valve operating condition at other than
idle condition:

Engine speed is below 6375rpm.

Vehicle speed is more than 14km/h.

Engine coolant temperature is more than 60C.
All above conditions are met for 4 seconds.


Results of Incorrect Operation
Poor idle, stalling and poor driveability can be caused
by:

Inoperative purge solenoid.

Damaged canister.

Hoses split, cracked and/or not connected to the
proper tubes.
Evidence of fuel loss or fuel vapor odor can be caused
by:

Liquid fuel leaking from fuel lines, or fuel pump.

Cracked or damaged canister.

Disconnected, misrouted, kinked, deteriorated o
r
damaged vapor hoses, or control hoses.
If the solenoid is always open, the canister can purge to
the intake manifold at all times. This can allow extra fuel
at idle or during warm-up, which can cause rough o
r
unstable idle, or too rich operation.
If the solenoid is always closed, the canister can
become over-loaded, resulting in fuel odor.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-77


F0: Diagnostic Trouble Code
F0: Read DTC Infor By Priority
F1: Clear DTC Information
F2: DTC Information
F0: History
F1: MIL SVS or Message Requested
F2: Last Test Failed
F3: Test Failed Since Code Cleared
F4: Not Run Since Code Cleared
F5: Failed This Ignition
F3: Freeze Frame/Failure Record
F1: Data Display
F0: Engine Data
F1: O2 Sensor Data
F2: Snapshot
F3: Miscellaneous Test
F0: Lamps
F0: Malfunction Indicator Lamps
F1: Relays
F0: Fuel Pump Relay
F1: A/C Clutch Relay
F2: EVAP
F0: Purge Solenoid
F3: IAC System
F0: RPM Control
F1: IAC Control
F4: Fuel System
F0: Fuel Trim Reset

F4: System Information
F0: MIL/System Status

F0: Diagnostic Trouble Code
The purpose of the "Diagnostic Trouble Codes" mode is
to display stored trouble code in the
ECM.
When "Clear DTC Information" is selected, a "Clea
r
DTC Information", warning screen appears.
This screen informs you that by cleaning DTC's "all
stored DTC information in the ECM will be erased".
After clearing codes, confirm system operation by test
driving the vehicle.
Use the "DTC Information" mode to search for a
specific type of stored DTC information.
History
This selection will display only DTCs that are stored in
the ECM's history memory. It will not display Type B
DTCs that have not requested the MIL ("Check Engine
Lamp"). It will display all type A and B DTCs tha
t
requested the MIL and have failed within the last 40
warm-up cycles. In addition, it will display all type C and
D DTCs that have failed within the last 40 warm-up
cycles.

MIL SVC or Message Request
This selection will display only DTCs that are requesting
the MIL. Type C and Type D DTCs cannot be displayed
using the MIL. Type C and D DTCs cannot be displayed
using this option.
This selection will report type B DTCs only after the MIL
has been requested.

Last Test Failed
This selection will display only DTCs that have failed the
last time the test run. The last test may have run during
a previous ignition cycle of a type A or type B DTC is
displayed. For type C and type D DTCs, the last failure
must have occurred during the current ignition cycle to
appear as last test fail.

Test Failed Since Code Cleared
The selection will display all active and history DTCs
that have reported a test failure since the last time
DTCs were cleared. DTCs that last failed more that 40
warm-up cycles before this option is selected will not be
displayed.

Not Run Since Code Cleared
This selection will display up to DTCs that have not run
since the DTCs were last cleared. Since any displayed
DTCs have not run, their condition (passing or failing) is
unknown.

Failed This Ignition
This selection will display all DTCs that have failed
during the present ignition cycle.

Freeze Frame/Failure Record
This selection will display stored various vehicle
information at the moment an emission related faul
t
when the MIL ("Check Engine Lamp") is commanded
on.
The Freeze Frame data will not be erased unless the
associated history DTC is cleared.

6E-80 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2
Parameter
Units Idle 2000rpm Definitions
23 A/C Request (Air
Conditioning) On/Off Off Off This displays the air conditioner request signal. This should display "On" when the air
conditioner switch is switched on.
24 A/C Clutch On/Off Off Off This displays whether the ECM has commanded the A/C compressor clutch "On" or
"Off".
25 EVAP Purge
Solenoid
(Evaporative
Emission) % 50
80 0 This displays the duty signal from the ECM to control the canister purge solenoid
valve.
26 Fuel Trim Cell 49
52 13
17 This displays dependent on engine speed and MAF sensor reading.
A plot of engine speed versus MAF amount is divided into the cells.
Fuel trim cell indicates which cell is currently active.
27 Fuel Pump On/Off On On This displays operating status for the fuel pump main relay.
This should display "On" when the key switch is turned on and while engine is
running.
28 Deceleration Fuel
Cutoff Active/ Inactive Inactive Inactive The ECM will command the deceleration fuel mode when it detects a closed throttle
position while the vehicle is traveling.
While in decreasing fuel mode, the ECM will decrease the amount of fuel delivered
by entering open loop and decreasing the injector pulse width.
29 Power Enrichment Yes/No No No The ECM will command power enrichment mode "Yes" when a large increase in
throttle position and load is detected.
While in power enrichment mode, the ECM will increase the amount of fuel delivered
by entering open loop and increasing the injector pulse width.
30 Vehicle Speed km/h or mph 0 0 This displays vehicle speed.
The vehicle speed is measured by ECM from the vehicle speed sensor.
31 Cam Signal Present/ Missing Present Present This displays input signal from the camshaft position sensor.
When the correct pulse is generated, signal is received.
32 PSP Switch
(Power Steering
Pressure) Normal Pressure /
High Pressure Normal PressureNormal PressureThis displays the power steering pressure signal.
This should display "High Pressure" when the steering is steered.
33 Security Code
Status Programmable/
Not
Programmable Programmable Programmable This should display "Programmable" when the correct security code & secret code
are programmed.
34 Security Code Okay/ Not Okay Okay Okay This should display "Okay" when the security code is correctly accepted.
35 Immobilizer
System Normal /
Abnormal Normal Normal This should display "Normal" when the immobilizer is correctly operated.
36 Malfunction
Indicator Lamp On/Off Off Off This displays operating status for the Check Engine Lamp.
This should display "On" when the Check Engine Lamp is turned on.
37 Time From Start   This displays the engine time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to 00:00:00

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -83

MISCELLANEOUS TEST
The state of each circuit can be tested by using
miscellaneous test menus. Especially when DTC cannot
be detected, a faulty circuit can be diagnosed by testing
each circuit by means of these menus.
Even DTC has been detected, the circuit tests using
these menus could help discriminate between a
mechanical trouble and an electrical trouble.
Connect Tech 2 and select "Powertrain", "3.5L V6 6VE1
Hitachi" & "Miscellaneous Test".

F0: Lamps
F0: Malfunction Indicator Lamp
When the Tech 2 is operated, "Malfunction Indicato
r
Lamp (Check Engine Lamp)" is turned on or off.
The circuit is normal if the "Malfunction Indicator Lamp
(Check Engine Lamp)" in the instrument panel is turned
on or off in accordance with this operation.

F1: Relays
F0: Fuel Pump Relay
When the Tech 2 is operated, fuel pump relay signal
turns ON or OFF.
The circuit is normal if fuel pump sound is generated in
accordance with this operation when key switch is
turned ON.

"F1: A/C Clutch Relay"
When the Tech 2 is operated, A/C clutch relay signal
turns ON or OFF.
The circuit is normal if A/C compressor clutch is
energized in accordance with this operation when the
engine is running.

F2: EVAP
F0: Purge Solenoid
When the Tech 2 is operated, duty ratio of EVAP purge
solenoid is changed 10%-by-10%.

Purge Solenoid
Engine Speed 800 RPM
Desired Idle Speed 762 RPM
Engine Coolant Temperature 80

C
Start Up ECT 50

C
Intake Air Temperature 30

C
Throttle Position 0 %
EVAP Purge Solenoid 10 %



Press "Increase" key.

Then, EVAP Purge Solenoid increases

10%-by-10%.


Press "Quit" Key.

F3: IAC System
F0: RPM Control
When the Tech 2 is operated, "Desired Idle Speed"
increases 50rpm-by-50rpm up to 1550rpm.
The circuit is normal if engine speed is changed in
accordance with this operation.
RPM Control
Engine Speed 850 RPM
Desired Idle Speed 850 RPM
Engine Coolant Temperature 80

C
Start Up ECT 50

C
Intake Air Temperature 30

C
Throttle Position 0 %
Desired Idle Speed 850 RPM



Press "Increase" key.

Then, Desired Idle speed increases

50rpm-by-50rpm up to 1550rpm. Engine speed is
also changed by this operation.


Press "Quit" Key.

F0: IAC Control
When the Tech 2 is operated, "Idle Air Control"
increases or decreases 10steps-by-10steps up to
160steps.
The circuit is normal if idle engine speed is changed in
accordance with this operation.
IAC Control
Engine Speed 875 RPM
Desired Idle Speed 762 RPM
Engine Coolant Temperature 80

Start Up ECT 50

Intake Air Temperature 30

Throttle Position 0 %
Idle Air Control 30 Steps



Press "Increase" key.

Then, Idle Air Control increases 10steps-by-
10steps up to 160steps.

Engine speed is also changed by this operation.


Press "Quit" Key.