EPA 2004 Fuel System

1
EPA 2004 Fuel System Mike Michalski April
2004
2
The session which I am about to start will be an
introduction to the EPA 2004 , Woodward MI-04
fuel system. Since many of the parts used are so
similar to any prior LPG fuel systems, I am not
going to go into the operational sequences of
components such as the mixer and the regulator ,
which have been used for years in LPG systems,.
Instead I will attempt to spend as much time as
possible talking about the components which have
not been common as well as the symptoms and
faults we have experienced to date with this
system.
3
The U.S. Environmental Protection Agency (EPA)
has adopted emission standards for several types
of previously unregulated non-road engines and
vehicles. The new standard that applies to our
forklifts is regulated by the section which
pertains to spark ignition non-road engines
powered by gasoline , liquid propane or
compressed natural gas and is rated over 25
horsepower. This presentation will be an overview
of the system CLARK has implemented to meet these
requirements
4
This regulation will be implemented In two
stages. The first stage was implemented into
engines manufactured in 2004. We identify this
as EPA 2004.
The second stage will take effect in 2007 and is
based on transient testing in the laboratory, and
will insure the engines will control emissions
when they operate under changing speed and loads
5

• The second level or Tier of emission standards
  required by the EPA (Environmental Protection
  Agency) Requires that
• The system meets all of the 2004 emission
  requirements
• The system must have the capability of
  maintaining a constant emission level at
  steady state operation
• The system must be able to compensate for
  component wear and for fuel variations
• The system must also be able to alert the
  operator if the emission levels exceed the
  required levels

6
The MI-04 fuel control system chosen by Clark is
designed to provide a complete, fully integrated
solution that meets or exceeds the EPA and CARB
requirements for 2004
7

• System Strengths
• Simplicity
• Only one additional fuel system component, the
  Trim Valve all remaining fuel parts are
  conventional
• Trim valve meters vacuum, not fuel
• Service with fault codes and manual-expensive
  tools not required
• Proven ECM
• Over 100,000 in use erratic behavior, failures
  identified
• Manufactured by Motorola quality, consistency
  excellent
• Self-Correcting
• Adaptive Learn allows adjusting for wear, fuel
  deposits
• Adapts to specific application-truck
  configuration, altitude, operation

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Emission Standards
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General Description
The MI-04 system is basically a closed loop
system. However, the system operates in an open
loop condition until the engine has done a
certain amount of work insuring that both the
engine and the O2 Sensor are sufficiently warmed
up to stay in control.
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General Description
During open loop operation, that is prior to the
HEGO (O2 Sensor) reaching its operating
temperature (Approximately 600 º F) the FTV
(Fuel Trim Valve) duty cycle is based upon a
programmed engine speed and load value. Once the
O2 Sensor is at operating temperature, the system
is in closed loop and the FTV duty cycle is
controlled by the feed back from the O2 Sensor.
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General Description
Now that we have established the base parameters
of the system operation, lets start into the
system cycle.
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General Description
The MI-04 is a closed loop system utilizing a
catalytic muffler to reduce the emissions level
in the exhaust gas
O2 Sensor
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General Description
In order to obtain the maximum effect from the
catalyst, an accurate control of the air / fuel
ratio is required. In this system, an SECM (Small
Engine Control Module) along with the O2 Sensor
is used to monitor exhaust gas content.
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General Description
The SECM controls the air / fuel ratio by
modulating the Fuel Trim Valve. The Fuel Trim
Valve in turn controls the secondary diaphragm
to vary the fuel mixture
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General Description
The MI-04 System also uses a Drive By Wire System
connecting the electronic accelerator pedal to an
electronic throttle control. There are no cables.
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General Description
The SECM uses several different sensors to gain
the information about the engine performance.
O2 Sensor
Engine Speed - VR Sensor Intake Manifold Air
Temperature and Absolute Pressure - TMAP Throttle
Position - TPS Engine Coolant Temperature
-ECT Accelerator Position - APP Oil Pressure
Switch Exhaust Gas - O2 Sensor
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The Rest of the MI-04 Components
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CA 55 Mixer
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CA 55 Mixer
The Model N- CA-55 -500TR mixer uses a piston
type air valve assembly to operate a gas metering
valve inside the mixer. The gas metering valve is
normally closed (spring loaded), requiring a
negative pressure (vacuum) signal, from a
cranking or running engine to open. The gas
metering valve controls the amount of fuel to be
mixed with the incoming air at the proper ratio.
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CA 55 Mixer
The only adjustment that can be made to the
N-CA55-500 TR mixer is the idle adjustment
setting The idle mixture screw is an air bypass
port, adjusting the screw inward blocks off the
port and enriches the idle mixture

• There are 2 ways to set the idle mixture
  adjustment. The first is with a Multi-Meter which
  has a duty cycle feature.
• The second is with a cable and a laptop.

This is the only adjustment required on the
entire system and should only be required if the
mixer is changed.
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This page is found in the EPA 2004 Manual located
in Parts PRO/pdf/Truck Troubleshooting/ EPA 2004
Service
22
Fuel Lock Off

• This Fuel Lockoff is a spring loaded electric
  solenoid in a normally closed position.
• 12 VDC power is supplied to the lockoff when the
  key is activated with the SECM providing the
  ground connection.
• It has a stall safety shutoff feature built into
  the system, closing the lockoff if the SECM
  detects a STALL condition.
• The SECM actually monitors 3 engine conditions
• CRANK When any engines are detected
• STALL Key on but no engines revolutions after 5
  seconds
• RUN When pre idle RPM is reached (700 RPM)

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Electronic Throttle

• The Bosch DV-E5 electronic throttle is an
  automotive based unit consisting of
• Throttle valve
• Throttle Valve Activator (DC Motor)
• Throttle Position Sensor (TPS)
• The throttle valve position is determined by the
  SECM based on engine load and input from the
  Accelerator Pedal.

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Electronic Throttle
TPS Gear Drive Pick up
TPS Potentiometer Contacts
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Electronic Throttle
The SECM calculates the correct throttle opening
that corresponds to the accelerator input. It
then makes adjustments needed for adjusting to
the engines current operating condition and then
generates an electrical signal to the throttle
valve activator. Feed back from the TPS
continually informs the SECM of the throttle
valve position. The default position for the
throttle plate is approximately 7 open if power
is removed for any reason.
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Fuel Trim Valve
The Fuel Trim Valve is a Bosch 2-way electric
solenoid valve and is controlled by a pulse width
modulated signal provided by the SECM. It meters
air valve vacuum into the atmospheric side of the
regulator secondary diaphragm.
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Fuel Trim Valve
The MI-04 System is calibrated to run rich
without the FTV. By increasing the amount of
times the FTV opens, (Modulation or Duty Cycle)
causes the air / fuel mixture to become leaner,
decreasing the duty cycle enriches the air fuel
mixture. When the pressure is reduced on the
regulators secondary side the secondary valve
will close and reduce the fuel flow which leans
out the air / fuel mixture
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Temperature / Manifold Air Pressure
Temperature Manifold Air Pressure
The SECM self-calibration and cross checking of
the TPS is accomplished by comparing the TPS
signal to a calculated throttle position in the
SECM software (Predicted TPS) In addition to the
throttle position sensor, a Temperature /
Manifold Absolute Pressure Sensor (TMAP) is used
to monitor intake manifold temperature and
pressure.
29
Heated Exhaust Gas Oxygen Sensor ( HEGO)
The zirconium type oxygen sensor has a hollow
internal element made of a ceramic material
(zirconium dioxide, ZrO2) which is also coated
with a layer of micro-porous platinum The outer
layer is exposed to the exhaust gas stream The
inner layer is vented to atmosphere and attached
to a wire that connects to the SECM.
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Heated Exhaust Gas Oxygen Sensor ( HEGO)
The O2 Sensor (SECM) generates a voltage signal
proportional to the amount of oxygen is the
exhaust. If the exhaust mixture is lean, the O2
voltage is below the set point and the FTV duty
cycle decreases to allow more fuel. If the
mixture is rich , the sensor voltage is above the
set point and the FTV duty cycle increases to
allow less fuel.
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Heated Exhaust Gas Oxygen Sensor ( HEGO)
OK ..lets get technical for a moment. The HEGO
(O2 Sensor) target voltage is 500 mVolts and
changes as a function of speed and load. When it
sends a voltage slightly less than 500mVolts, the
SECM interprets the air/fuel ration to be lean
and it decreases the FTV duty cycle which lowers
the amount of vacuum to the regulator which will
then richen the air/fuel mixture. Conversely, if
the SECM receives a higher than 500mVolts from
the HEGO, it interprets the mixture as too rich
and increases duty cycle of the FTV and leans out
the mixture.
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Catalytic Muffler
All exhaust gases pass through a catalyst inside
the muffler. The catalyst is a dense honeycomb
structure coated with precious metals.(Platinum,
Palladium Rhodium) the chemical reaction
converts pollutants into less harmful gases.
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Catalytic Muffler
In a nutshell. The catalytic muffler has a
reduction cycle and a oxidation cycle. Reduction
Catalyst reduces NOx to nitrogen and carbon
dioxide (NOx gt N2 CO2) Oxidation Catalyst
reduces the unburned hydrocarbons and carbon
monoxide by oxidizing (burning) them over
platinum and palladium which reduces them to
water and carbon dioxide. (HC CO gt H2O CO2)
34
Catalytic Muffler
In Summary,by using the signal from the O2 Sensor
the SECM can increase or decrease the amount of
oxygen in the exhaust by modulating the FTV. This
makes sure the engine is running close to
stoichiometric. Stoichiometric Mixture
Definition is .just enough air to theoretically
burn all of the fuel , with no oxygen or unburned
fuel left after combustion. Also commonly
referred to as Stoich.
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SECM (Small Engine Control Module)
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SECM
While in open loop, the FTV duty cycle is based
on tables using engine speed, load and
temperature. Once the O2 Sensor is at operating
temperature , the fuel management goes to closed
loop for all steady state conditions, from idle
through full throttle. In closed loop, the FTV
duty cycle is based on feed back from the O2
Sensor.
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Accelerator Control
The accelerator pedal uses 2 potentiometers (APP1
APP2) to detect pedal position. The SECM uses
these inputs to calculate the throttle position
required.
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Ignition Control
The MI-04 System uses a distributor based system
for the Mitsubishi 2.0 2.4 Liter engine along
with a 30-5 Variable Reluctance signal. (The GM
engines use the GM EST System) The distributor
does not use any internal advance mechanism. The
timing is calculated by the SECM based on RPM
,TPS TMAP
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Ignition Control
The SECM can read RPM as low as 50 RPM with the
30-5 system. This allows the SECM to synchronize
the input faster creating shorter crank time,
more accurate timing and better cold starting
The VR Sensor is mounted on a crank case bracket.
The set up gap is adjustable and it provides all
of the speed (RPM) feedback to the SECM.
7
40
Ignition Control
The MI-04 system for 2.0L/2.4L engines use a
single coil which incorporates the ignition
driver circuitry inside the coil itself. The
SECM signals the smart coil when to begin its
dwell cycle then the coil waits for the trigger
signal from the SECM. The smart coil
eliminates the need for a driver circuit inside
the SECM or externally from the coil. Using a
single VR sensor and smart coil eliminates
multiple sensors and coil packs used in more
complex ignition systems.
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Ignition Timing
Using the timing indicator on the crankshaft
pulley, set the engine on 0 (zero) degrees Top
Dead Center (TDC) of number 1 cylinder
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Ignition Timing
Verify that the distributor rotor is lined up
with number 1 cylinder on the distributor
cap. Remove the distributor rotor and dust cover
so that the internal VR sensor and signal rotor
gear are visible.
43
Ignition Timing
The internal VR sensor inside the distributor is
not used by the SECM for a speed reference with
the 2.0L/2.4L engine and its wiring harness does
not connect to the system. The distributors
internal VR sensor is only used as an alignment
reference point for setting the correct
distributor position. Loosen the distributor,
hold down nut and rotate the distributor so that
the signal rotor gear tooth of the 1 cylinder
(tooth opposite the flat side of the distributor
shaft) lines up with the sensor pickup.
44
Ignition Timing
To correctly set the distributor, align the
center of the 1 cylinder tooth with the leading
edge of the VR sensor pickup. Keep in mind that
the distributor rotates in a clockwise direction.
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Ignition Timing
Once the proper alignment is obtained, lock the
distributor in place by tightening the hold down
nut to the specified torque value and re-install
the rotor, dust cover and rotor cap. Lock the
distributor in place by tightening the hold down
nut to the specified torque value. After you
have completed setting the distributor alignment
you will need to adjust the VR sensor used by the
SECM for speed reference.
46
Ignition Timing
Rotate the crankshaft pulley so that one of the
gear teeth on the timing wheel aligns in the
center of the VR sensor. Using a feeler gauge
loosen the sensor retaining bolts and adjust the
gap between the sensor and the gear tooth from
1.25mm to 1.5mm. Rotate the crankshaft pulley
180 degrees and align a timing gear tooth in the
center of the VR sensor pickup. Verify that the
sensor gap is still within 1.25mm to 1.5mm.
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MI-04 Fault Action Descriptions
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Fault Action Description
Each fault detected by the SECM is stored in
memory FIFO (First In First Out) and has a
specific action or result that takes place.
ENGINE SHUTDOWN The most severe action is an
Engine Shutdown. The MIL will light and the
engine will immediately shutdown, stopping spark
with the fuel lock-off closing.
LIMP HOME MODE ( POWER LIMITING) The Limp Home
Mode reduces the lift truck power, but will
provide to enable the operator to move the truck
safely , but not use for normal operation.
MIL ONLY ( STORED CODE) The MIL will light by an
active signal provided by the SECM indicating a
fault condition but no further action will take
place.
The following are some examples of these action
modes
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Fault Action Description ENGINE SHUTDOWN
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Fault Action Description Low Oil Pressure
Shutdown
On the Clark Gen2 trucks, this is a function of
the Instrument Panel not the fuel system and is
evident by a dash icon for the oil pressure being
illuminated and the flashing along with the dash
alarm. However, on the CMP Models this becomes a
function of the fuel system. This will be an
engine shutdown displaying a 52 code in the MIL
system.
51
Fault Action Description High Water Temperature
Shutdown
On the Clark Gen2 trucks, this is also a
function of the Instrument Panel not the fuel
system and is evident by the over temperature
sequence and the flashing along with the dash
alarm. ( Remember , the Gen 2 series does not
have a 16 code in the MIL system) However, on
the CMP Models this becomes a function of the
fuel system. This will be an engine shutdown
displaying a 16 code in the MIL system.
52
Fault Action Description LIMP HOME (POWER LIMIT)
53
Fault Action Description STORED CODE
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MI-04 Basic Troubleshooting
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Basic Troubleshooting
The MI-04 Systems are equipped with built in
fault diagnostics.
Note Older units may have the Air Restriction
symbol as the MIL
Items such as fuel level, plugged fuel lines,
clogged fuel filters and malfunctioning pressure
regulators may not set a fault code by the Small
Engine Control Module (SECM). Methods for
troubleshooting plugged fuel lines, fuel filters,
vapor lines and cylinder tank problems apply to
the MI-04 system as they did with a Tier I
system.
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Basic Troubleshooting
Detected system faults can be displayed by the
Malfunction Indicator Lamp (MIL) as Diagnostic
Fault Codes (DFC) or flash codes, or viewed in
detail with the use of the service tool
software. When the ignition key is turned ON the
MIL will perform a self-test, illuminate once and
then go OFF. If a detected fault condition
exists, the fault or faults will be stored in the
memory of the small engine control module
(SECM). If an Active Fault occurs while the
engine is running the MIL will illuminate and
remain ON. This signals the operator that a
fault has been detected by the SECM.
57
Basic Troubleshooting
Turn the key on without cranking the
engine Depress the accelerator to the floor 3
times within 5 seconds This will begin the fault
display process
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Basic Troubleshooting
Reading Diagnostic Fault Codes All fault codes
are 2 digit When the fault codes are retrieved
(displayed) the MIL will flash for each digit
with a short pause ( .5 seconds) between digits
and a long pause (1.2 seconds) between fault
codes There will be a 12 code to start and a 12
code will indicate the end or that it restarting
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Basic Troubleshooting
Turn the key on without cranking the
engine Depress the accelerator to the floor 10
times within 5 seconds This will the clear the
faults
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MI-04 Basic Troubleshooting What have we found
so far..
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31 Code The 31 code only is found on units with
an SECM with RBAE Software or newer The unit will
set a 31 code anytime the truck cuts out with the
key on. This includes running out of fuel or
turning the key back to off before the truck
starts. This can also be the result of a SECM
reset due to electrical interference. In order to
verify this fault, a cable and crypt token is
required. The MotoViewer will record occurrences
in the test screen/ SECM / Reset Counter
62
This is the page from the latest Service Manual
which is still in Draft form.
63
31 Code If you are experiencing a symptom of
intermittent shutdown or, an extreme fluctuation
of RPM, maybe described as stuttering, it could
be a 31 code . First verify that you have a good
chassis ground. If you do not have a Cable set,
temporarily relocate the SECM from its current
location on the chassis to a loose mount (wire
tie) under the floor board. If the shutdowns
stop, contact us for instructions. If you have a
cable set, download RBAE or newer software into
the SECM. It will then record 31 codes if that is
what the the problem is.
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31 Code If a 31 code is verified , either by
elimination of the shutdown or by use of a cable
which allows you to see the number of SECM resets
in the Test Screen. A new SECM part number is
available and incorporates a capacitor to
eliminate the voltage spikes causing the
shutdown.
65
Smelly Exhaust We have found that out of the few
complaints we have had, they were the result of
the mixer washer cracking and causing the mixer
piston to operate too slow. This causes the
mixer to remain rich too long and thus creating
either an ammonia or rotten egg smell The
checkout is..
66
It is not necessary to remove the air horn. You
only need to remove the fuel lines and air inlet,
disconnect the elec. plug, then the 4 mounting 5
mm bolts to access the bottom of the mixer. Then
remove the 4 torx screws to remove the piston..
Requires torx t-25 security bit to remove the 4
screws to access the mixer piston
5MM ball end Metric Allen required 4 bolts
Use extreme caution to not damage this o ring
when removing and reinstalling the mixer. Hold
the throttle assembly as it does not need to be
lifted up. Only the mixer and adapter.
See Page 2 for inspection
67
Remove Mixer
Remove the piston
Inspect disc for cracks
68
68 Code C152 Cushion only Accelerator pedal
assembly will slip past the stop under certain
conditions and throw a 68 code momentarily . It
does not affect the truck operation after the
pedal is returned to the up position. While the
code is active, the truck will experience reduced
performance because it is an error in the pedal
input. Fix is a rework of the pedal until a
redesign is completed by the vendor
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Pedal 8033089 will cause a 68 code due to
incorrect voltage. This apparently is caused when
the pedal is depressed with a left to right
depression effort, the pedal misses the stop and
slides to the right and travels beyond the stop
allowing the voltage to go beyond limits.
Rework consists of removing the rubber stop and
drilling through and inserting a bolt to stop
pedal travel at same height as the stop rim..
Pedal in up position
Pedal depressed but,missed stop
Pedal depressed against the stop
70
No Code Complaint of slow starting. We have
observed the following items If you start
cranking before the fuel lock off opens and the
throttle plate test cycles, the truck will not
start until these cycles are completed. You can
hear the 2 clicks. Crank time appears to range
between 1 1/2 to 4 seconds depending on several
factors. If battery voltage drops below 9.0
volts, the lockoff will not open and the truck
will not start. If it does not start in about 5
seconds , recycle the key switch.
We are presently working with the vendor to
reduce the crank time.
71
No Code Complaint of intermittently truck will
not accelerate after initial start up. Insure
that the operator is not stepping on accelerator
while cranking, it will default the pedal .
Pedal will have to be recycled prior to initial
acceleration.
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Installing Laptop System Software
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934427
USB - Can Converter Cable Dealer Net 645.00
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934428
Tier 2 Software Package Dealer Net 405.00
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The Mototron CD included with part number 934428,
has instructions for loading onto your laptop,
however, the CD also is self guided through the
installation process. Just follow the guide
instructions.
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If you are unsure, cancel the installation , go
to the file pull down and click open. From the
menu, click on MotoService Install Info.pdf, it
will give you the information regarding the
installation
NOTE Once this CD is loaded to your laptop, it
will not be required again. Place it in a safe
storage place. ALSO. If it has been loaded for
Either Clark or Daewoo, it is not necessary to
load it again,
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Once the installation is complete, you will
need to download the necessary program files from
Clark Intranet. These files are in PartsPro /
Truck Troubleshooting/ EPA 2004 System
Service/EPA 2004 Program Files.
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pdf
Now you will need to down load the files from
Clark PartsPRO. These files are found in pdf.Files
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First, open and read the EPA 2004 Program
Instructions
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Now , open the EPA 2004 Program Files
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These files will have to be downloaded for
installation in your laptop
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File transfer from the Parts PRO system will vary
depending on the capability of your laptop and
the operating systems available to you.
Therefore I will not cover this but if you
experience any problem in the downloading of your
files please feel free to call me Mike Michalski
_at_ 859-422-6423
89
The MotoViewer requires a display file to
operate. These are labeled as MI_4
Diagnostic_Display_revxx.dis. You will only need
the latest revision level of this file. This file
needs to be placed into the directory
C\ECUFiles\Displays.
90
Display files to Displays folder
ECU Files
91
The next file is VARSPEED????.dll with the
question marks being replaced by the versions of
software available. There is a .dll file for each
version of the software. You should load all the
.dll files in the directory. These files need to
be placed into the directory C\ECUFiles\Tdbdll.
NOTE You must have a .dll file for every
software version used. Do Not delete any of these
files.
92
dll files to TDBDLL folder
ECU Files
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The next file is VARSPEED????_??_?_???_?_???.mfu,
again with the question marks replaced with the
versions of the software. These files are
required only if a newer version of software is
required for trucks already in the field. These
fles are used by Moto-Update to bring the SECM in
a field truck update to the latest factory
standards. The structure of these files ,
VARSPEEDXXXX, the letters replaced by the Xs is
the software version. It will match the .dll
files. The rest of the numbers and letters
designate the software for each truck model. All
of these files need to be placed into the
directory C\ECYFiles\Updates
94
mfu files to Updates folder
ECU Files
95
NOW we are ready to use the cable
96
You may have already created a shortcut to your
MotoUpdate and MotoViewer as described in the
Instructions found on the CD. If not you will
need to click on the Start Icon and then enter
the Program Files and then select MotoService/
MotoViewer
97
After clicking on the MotoViewer Icon, With the
Ignition Key on, you will get this screen. Note
that it says (Clark Service Dept) at the
top. Click on File and then on Open If it says
Unlicensed, You are not properly connected or do
not have the correct crypt token. Back up and
verify all connections , insure key is on etc.
98
Now you will click on the newest Rev Level, which
in this case is Rev F
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MI-04 Troubleshooting Downloading new Software
101
There may be occasions when new software will be
installed into your existing SECM. The following
is the procedure to do this using a cable and
crypt token with your laptop.
102
You may have already created a shortcut to your
MotoUpdate and MotoViewer as described in the
Instructions found on the CD. If not you will
need to click on the Start Icon and then enter
the Program Files and then select MotoService/
MotoUpdate
103
This is the first screen you will get.click on
Nextgt
104
Then you will get this screen which will advise
what software is in the SECM.First highlight the
software to install, in this case it is
VARSPEEDRBAG_01_2.5 cnf_000. Then click Next
gt
105
Next you will get this advisory, insure your
laptop is not in low battery warning when you
click OK to start the download.
106
You will get the download screen ..
107
Successful download! Click Finish
108
MI-04 Troubleshooting Using the Chart Function
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I usually rename the RUN SCREEN.log to either the
truck serial number or the reason I am charting.
Then Click OK
112
Right click on selected function to chart
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3
1
2
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Repeat for all items to be monitored
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Chart is running
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This is an example of the data we can retrieve
with a chart
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This is an example of the data we can retrieve
with a chart
127
We have had some preset charts developed by
Woodward for examination of a specific
check. For example Cold Start Cold Running