Service Training

Meeting Guide 712 SESV1712

November 1999

TECHNICAL PRESENTATION

3406E ENGINE CONTROLS

ELECTRONIC UNIT INJECTION (EUI)
3406E ENGINE CONTROLS
ELECTRONIC UNIT INJECTION (EUI)
MEETING GUIDE 712 SLIDES AND SCRIPT
AUDIENCE
Level II--Service personnel who understand the principles of engine systems operation, diagnostic
equipment, and procedures for testing and adjusting.

CONTENT
This presentation is designed to prepare a service technician to identify the components, explain their
function, and service the 3406E Electronic Unit Injection (EUI) engines in the D350E and D400E Series
II Articulated Trucks.

OBJECTIVES
After learning the information in this presentation, the serviceman will be able to:
1. locate and identify the major components in the 3406E EUI system;
2. explain the functions of the major components in the 3406E EUI system;
3. trace the flow of fuel through the fuel system; and
4. trace the flow of current through the engine electrical system.

PREREQUISITES
Interactive Video Course "Fundamentals of Electrical Systems" (CD ROM) TEMV9002
Electronic Technician (ET) Self Study Course (Included with ET Dealer Additions CD) JEBD3003
Caterpillar Machine Electronics Course (Five Modules) SEGV3001
through
SEGV3005

Prior training in systems operation and testing and adjusting procedures for the 3406E engines should
be completed before participating in this training session. Additionally, the participants should have PC
skills including training in Windows 95/98ª and the most current Electronic Technician (ET) software.

Estimated Time: 8 Hours

Visuals: 80 (2 X 2) Slides
Serviceman Handouts: 3 Line Drawings
Form: SESV1712
Date: 11/99

© 1999 Caterpillar Inc.

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SUPPLEMENTARY TRAINING MATERIAL

Brochure "Caterpillar Electronic Technician" NEHP5614

Wall Chart "3406E Engine" LEWH6740

Training Book "Easy PCs" (available through the Cat Literature System) LEBV5169
Also available from bookstores. Published by Qui Corporation

Training Books "Windows 95 for Dummies/Windows 98 for Dummies"

Published by IDG Books
IDG Books World Wide Website: http://www.idgbooks.com
Available from bookstores
Caterpillar EUI Fuel System (Interactive CD ROM) RENR1391-01

RECOMMENDED 3406E EUI TOOLING

Caterpillar Electronic Technician Software, Users Manual and Getting Started Book JEBD3003
Caterpillar Electronic Technician Single Use License JERD2124
Caterpillar Electronic Technician Annual Data Subscription (All Engines and Machines) NEXG5007

Communication Adapter 7X1700

PC to Communication Adapter Cable 7X1425
Communication Adapter to Machine Cable 139-4166
(combined ATA and CDL Data Link cable; replaces 7X1570 and 7X1412)
Digital Multimeter (Fluke 87) 9U7330
Cable Probes 7X1710
Timing Calibration Probe (Magnetic Pickup) 6V2197
Timing Calibration Probe Adapter Sleeve 7X1171
Timing Calibration Probe Cable 7X1695
Unit Injector Height Adjustment Tool 9U7227
Engine Turning Tool 9S9082

REFERENCES
Troubleshooting Manual "3406E Engine for Caterpillar Built Machines" RENR1366
Systems Operation Testing and Adjusting "3406E and 3456 Engines
for Caterpillar Built Machines" RENR1363
Disassembly and Assembly "3406E and 3456 Engines for Caterpillar Built Machines" RENR1364
Specifications Manual "3406E and 3456 Engines for Caterpillar Built Machines" RENR1362
Product Reference Guide "Jake Brake Retarders for Caterpillar Engines" RENR1370
Tool Operating Manual "Using the Communication Adapter" SEHS9264
Parts Manual "D400E Series II Articulated TrucksÓ SEBP2784
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TABLE OF CONTENTS

INTRODUCTION ..................................................................................................................5
Overview ..........................................................................................................................6
Major Components ...........................................................................................................7

ELECTRONIC CONTROL SYSTEM ................................................................................27

Introduction.....................................................................................................................27
Fuel Injection .................................................................................................................30
Fuel Injection Control System .......................................................................................32

SYSTEM CALIBRATIONS.................................................................................................45
Speed/Timing Sensor Calibration ..................................................................................45
Injector Calibration ........................................................................................................50
Pressure Sensor Calibration ...........................................................................................51

FUEL SUPPLY SYSTEM ...................................................................................................53

Introduction ....................................................................................................................53
System Fuel Flow ..........................................................................................................54

SYSTEM POWER SUPPLIES ............................................................................................61

Introduction ....................................................................................................................61
ECM Power Supply .......................................................................................................62
Injector Power Supplies .................................................................................................65
Analog Sensor Power Supply ........................................................................................66
Digital Sensor Power Supply .........................................................................................67

ELECTRONIC SENSORS AND SYSTEMS .....................................................................69

Introduction ....................................................................................................................69
Speed/Timing Sensors ....................................................................................................70
Analog Sensors and Circuits ..........................................................................................72
Digital Sensors and Circuits ...........................................................................................82
Engine Shutdown Systems .............................................................................................85
Ether Injection System ...................................................................................................87
CAT Data Link ...............................................................................................................88
Logged Events ................................................................................................................90
Caterpillar Monitoring System ......................................................................................91
Conclusion .....................................................................................................................92

SLIDE LIST .........................................................................................................................93

SERVICEMAN'S HANDOUTS ..........................................................................................94

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INTRODUCTION

This presentation discusses 3406E Electronic Unit Injection (EUI) Engine

Controls in D350E and D400E Series II Articulated Trucks.

The topics are sequenced as follows:

- Introduction and Major Components

¥ Major topics - Electronic Control System
- Fuel Supply System
- System Power Supplies
- Electronic Sensors and Systems

INSTRUCTOR NOTE: The presentation refers to and describes

Electronic Technician (ET) as the programming tool for the 3406E
engine. For this reason, it is essential that students demonstrate
competence in Windows 95/98/NTª and the Electronic Technician
(ET) program prior to starting this training session. Also,
competence in 3406E basic engine systems and maintenance must be
demonstrated.
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Overview

The 3406E engine equipped with the EUI fuel system is available in
construction equipment and other applications.

EUI engines have many features and benefits not possible with
¥ System features and mechanical fuel systems. These features include a very clean exhaust,
benefits
improved fuel consumption and cold starting, simplified maintenance,
fewer moving parts, improved diagnostics and reduced operating costs.

The system has additional advantages which will be covered later in this
presentation.
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FUEL GALLERY

EUI
EJECTORS

PRIMING PRESSURE
PUMP REGULATOR

ECM SECONDARY
FILTER FILTER BASE PRIMARY
(2 MICRON) FILTER
PRIMING PUMP TEMPERATURE
SENSOR RELIEF
CHECK VALVES VALVE
TRANSFER WATER
PUMP SEPARATOR

TANK

Major Components

This schematic shows the fuel flow through the various mechanical
¥ Fuel flow
components in the EUI fuel system. A detailed explanation of the system
and the various components follows later in this presentation.

The electronic components in the EUI fuel system are very similar to
¥ Components similar those used in the 3500B EUI engine. They are also similar to the
to 3500 EUI 3408E/3412E HEUI systems. However, in the EUI system the injectors
are actuated by a camshaft.

The injectors are mechanically actuated and electronically signalled to

¥ Injectors are start injection.
mechanically
actuated, electrically
signalled
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3 2 6 5

This slide shows the six major types of components in the EUI fuel
system.

¥ Six major system

- ECM (1)
components: - Throttle Position Sensor (2)
1. ECM
2. Throttle position - Speed/Timing Sensor (3)
sensor
3. Speed/timing - Injector (4)
sensor
- Temperature Sensor (5)
4. Injector
5. Temperature sensor - Pressure Sensor (6)
6. Pressure sensor
The data link (not shown) provides a two-way communication path
between the EUI system and the remaining electronic circuits or systems
on the machine. The CAT Data Link also allows the service tool to
communicate with the engine electronic system.

NOTE: Only one example of each sensor (pressure, temperature and

speed/timing) is shown in this view.
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¥ ECM (arrow) The principal component in the EUI system, the Electronic Control
Module (ECM), is mounted on the left side of the engine.

The ECM (arrow) is the "heart" of the engine. The ECM performs engine
governing, timing and fuel limiting. It also reads sensors and
communicates to the instrument display system through the CAT Data
Link.

This series of ECM can be recognized by the two 40 pin connectors.

Although similar in appearance to the 3408E/3412E HEUI ECM, they are
not interchangeable.

The Personality Module is used by the ECM to store all the rating
information for a particular application. The Personality Module cannot
¥ Personality module
be physically replaced, but must be flash programmed (reprogrammed)
not serviced
using a PC. This ECM has no Personality Module Access Panel.
¥ Flash programming
used for updates Among the visible components are the Wiring Harness and 40 Pin
Connectors to the ECM.
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3
4 2

¥ System components: Other components located on the left rear of the engine, starting from the
1. Injector connector top, are as follows:
2. Ground stud
3. Turbo outlet
pressure sensor
The Injector Connector (1) connects all the injectors to the ECM.
4. Inlet air temperature The Ground Stud (2) used to provide a ground for the ECM.
sensor
5. Timing calibration The Turbo Outlet (Boost) Pressure Sensor (3) used by the ECM to
connector provide fuel/air ratio control.
6. Fuel lines
The Inlet Air Temperature Sensor (4) used by the ECM to protect
the engine against excessive air inlet temperatures caused by a
plugged air to air aftercooler.
The Timing Calibration Connector (5) located just above the ECM
is used to connect the Timing Calibration Sensor to the ECM in order
to calibrate the (upper) Speed Timing Sensor. This process also
requires the use of ET.
The fuel lines (6) direct fuel through the ECM for cooling purposes.
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1. Secondary fuel filter The Secondary Fuel Filter (1) is mounted on the left side of the D400E
engine compartment, and can be serviced from the outside through an
2. Priming pump
access panel.

The Fuel Priming Pump (2) is mounted on the filter housing.

The filter should be installed dry. If it is necessary to fill the filter, this
should be performed using the priming pump. The filter should not be
filled using any other method, other than starting the engine. This engine
will normally purge the air from a new filter quite quickly.

The fuel manifold contains the fuel pressure regulator valve necessary to
maintain pressure between the transfer pump and the injectors and returns
excess fuel to the tank.

¥ Fuel temperature The Fuel Temperature Sensor is also located on the filter housing. The
sensor ECM uses the sensor's output to correct any power deficiencies due to
high fuel temperatures. The ECM maintains the same mass flow (within
certain limits) to the injectors, regardless of fuel density changes due to
temperature.
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¥ Coolant temperature The engine Coolant Temperature Sensor (arrow) is located on the front
sensor (arrow) of the engine, below the thermostat housing. This sensor is used with the
ECM to control various functions. The following systems or circuits use
the Temperature Sensor output to the ECM:

- The Caterpillar Monitoring System Coolant Temperature Gauge

¥ Sensor functions
and the High Coolant Temperature Warning Alert Indicator LED
on the Caterpillar Monitoring System panel.
(The information is transmitted over the CAT Data Link.)

- The Engine Demand Fan Control, if installed, uses the sensor

signal reference to provide the appropriate fan speed.

- The Cat Electronic Technician (ET) status screen shows the

coolant temperature indication.
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2
1

1. Atmospheric The Atmospheric Pressure Sensor (1) is installed in the cylinder block
pressure sensor and is vented to the atmosphere within the engine. This sensor has
various functions which are fully described later in the presentation.

Briefly, the sensor performs the following functions:

- Ambient pressure measurement for automatic altitude

¥ Sensor functions compensation, automatic air filter compensation and ET.

- Absolute pressure measurement for the fuel ratio control, and

also ET and Caterpillar Monitoring System panel (gauge) pressure
calculations.

Just to the right of the Atmospheric Pressure Sensor is the Timing

Calibration Connector (2). This connector is used in conjunction with a
2. Timing calibration
Timing Probe and wiring harness to calibrate the Speed/Timing Sensors.
connector
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3
2

10

¥ Speed/timing sensors: The Speed/Timing Sensors are located behind the timing gear cover, as
1. High speed shown here: high speed sensor, upper position (1), cranking speed sensor,
2. Cranking speed
lower position (2).

At the front of the engine on the left side of the cylinder head is the
3. Turbo outlet Turbo Outlet (Boost) Pressure Sensor (3). This sensor is used with the
pressure sensor ECM to control the air/fuel ratio electronically. This feature allows very
precise smoke control, which was not possible with mechanically
- Used for air/fuel ratio
governed engines.
control

The sensor also allows boost pressure to be read using the service tool.

NOTE: The Air Fuel Ratio Control cannot be manually adjusted on

the D350E or D400E Engines.
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11

¥ Machine interface The Machine Interface Connector (arrow) links the engine wiring harness
connector (arrow) to the machine wiring harness. Circuits such as the ECM power supply,
the throttle position sensor, the data links and the shutdown circuits are
routed through this connector.
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12

¥ Injector connector The injector connector is located in the valve cover and supplies current
to all six injectors.

In this 12 pin connector, nine pins are used for the injector solenoids and
three are used for the retarder solenoids. (The six injector return wires are
paired into three connectors.)

This injector circuit is described in detail later in the presentation (System

Power Supplies).
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13

¥ Oil pressure sensor The oil pressure sensor (arrow) is located above the engine oil cooler.
(arrow) This sensor is used to warn the operator of low oil pressure. The ECM
will log an event if the sensor registers low oil pressure under certain
conditions. These conditions are fully described later in the presentation.

¥ Six analog sensors This sensor is an analog type. Six analog sensors are installed on the
D350E/D400E Series II engines:

- Coolant
- Temperature
- Fuel Temperature
- Inlet Air Temperature
- Atmospheric Pressure
- Turbocharger Outlet Pressure
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14

¥ Inlet air temperature The Inlet (manifold) Air Temperature Sensor (arrow) is located on the left
sensor (arrow) side of the engine, above the ECM. This sensor is used to warn the
operator of potentially damaging conditions causing the air supply to be
overheated.

High air inlet temperatures can cause very high exhaust temperatures in a
ratio of three to one. For example: The air inlet temperature can rise
from 27 to 93¡C (100 to 200¡F). This condition can cause the exhaust
temperature to rise from 538 to 704¡C (1000 to 1300¡F), resulting in
possible exhaust valve or turbocharger damage.
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15

Timing Calibration Components

¥ Calibration plug When performing timing calibration, the Timing Calibration Probe is
(arrow) installed in the cylinder block by first removing the plug (arrow).

¥ Timing calibration A timing calibration jumper cable is installed into the timing calibration
sensor installation
connector just above the ECM.

The Timing Calibration Probe actually takes the place of the lower
(cranking) Speed Timing Sensor in the circuit as only the upper (high
speed) sensor is calibrated.
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16

¥ Crankshaft slot The crankshaft has a machined slot on the counterweight as shown
(arrow) (arrow). The slot is located just behind the No. 1 rod bearing.
¥ Timing calibration
probe installation
The Timing Calibration Probe is inserted through the block and generates
a signal from the crankshaft slot.

¥ Machined face used to A machined face (below the arrow) is used to set the clearance between
set clearance the probe and the crankshaft.

This process is explained in detail later in the presentation.

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17

Machine Mounted Components

The Throttle Position Sensor (arrow) is mounted on the throttle pedal and
¥ Throttle position
sensor (arrow)
is used to signal the desired engine speed from the operator to the ECM
electronically.

No mechanical connection exists between the pedal and the governor

(ECM).
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1 2

18

1. Ground level The Ground Level Shutdown Switch (1) is located below the cab door. In
shutdown switch an emergency, this switch permits shutting down the engine from outside
the cab.

This switch also provides a convenient way of electrically isolating the

injectors during cranking for maintenance purposes.

To the right of this switch is the Battery Disconnect Switch (2). The
2. Battery disconnect disconnect switch should always be used to isolate the ECM when electric
switch arc welding is performed on the machine.
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19

¥ Service tool The D350E/D400E Service Tool Connector (arrow) is located in the cab
connector (arrow) on the right side console.

The Service Tool Connector is used to connect the ET service tool to the
¥ Allows access to ET
machine electrical/electronic systems. The connector allows the service
service tool
tool to access the ECM's to read diagnostic and status screen information,
perform calibrations and other functions.
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3406E ENGINE SYSTEM BLOCK DIAGRAM (D400E)

ENGINE MOUNTED COMPONENTS

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR
GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)
INLET AIR TEMPERATURE SENSOR
OIL PRESSURE SENSOR
ATMOSPHERIC PRESSURE SENSOR

TURBO OUTLET PRESSURE SENSOR

20

¥ Engine component This schematic identifies the D400E Series II external EUI engine
identification electronic and electrical components.

The components shown on this diagram are mounted on the engine and
those on the following diagram are machine mounted.
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3406E SYSTEM BLOCK DIAGRAM (D400E)

MACHINE MOUNTED COMPONENTS

GROUND DISCONNECT SWITCH

BOLT
MACHINE INTERFACE CONNECTOR

24 V
UNSWITCHED POWER
ENGINE RETARDER SELECTOR SWITCH
1 15 AMP KEY
BREAKER MAIN SWITCH
2 LOW/MED/HIGH POWER
RELAY
3
4
MAIN POWER

2
3 MED THROTTLE SENSOR THROTTLE PEDAL
4 HIGH

GROUND LEVEL
SHUTDOWN SWITCH
ENGINE RETARDER LAMP

STARTING AID SWITCH + BATTERY RELAY ETHER START VALVE

CAT MONITORING SYSTEM
CYLINDER

10
15
20
AUT P ENGINE
5 25
R X100
MPH 44
0 km/h 30
24 V

ET SERVICE TOOL
CAT AND ATA DATA LINK

21

¥ Machine mounted This schematic identifies the machine mounted engine electronic and
component electrical components.
identification

INSTRUCTOR NOTE: At this time, it is recommended that each

component be located on the machine and the function of each
reviewed with the students. A list of the components follows.

If an engine is available out of a machine, component identification

will be easier because some components are difficult to see.

Some additional (used/defective) components available for

examination on a table will be helpful.

➥
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ENGINE COMPONENT LIST

Electrical Components

ECM 40 Pin Connectors (2)

Timing Calibration Installation Location
Timing Calibration Connector
Timing Sensor, High Speed
Timing Sensor, Cranking Speed
Coolant Temperature Sensor
Inlet Air Temperature Sensor
Atmospheric Pressure Sensor
Turbocharger Outlet Pressure Sensor
Oil Pressure Sensor
Fuel Temperature Sensor
Machine Interface Connector
Engine and Machine Ground Bolts
Service Tool Connector
Throttle Position Sensor
Shutdown Switches
Disconnect Switch

Mechanical (Fuel Delivery) Components

Primary Filter and Water Separator

Secondary Filter
Priming Pump
Transfer Pump
Pressure Regulator Valve
Injectors (6)
Cylinder Head Fuel Passage
ECM Fuel Cooling Passage and Connectors
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ELECTRONIC CONTROL
SYSTEM

22

ELECTRONIC CONTROL SYSTEM

Introduction

This section of the presentation explains the Electronic Control System

including the following components:

- ECM
- Personality Module
- Timing Wheel

Also covered are the following subsystems and related procedures:

- Timing Control
- Fuel Quantity Control
- Speed Control
- System Calibrations
- Cold Modes
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23

¥ ECM: The Electronic Control Module (ECM) functions as the governor and fuel
system computer. The ECM receives all the signals from the sensors and
- Governor
energizes the injector solenoids to control timing and engine speed.
- Fuel system
computer
- Injection timing The ECM is used in most 3406E, 3456, 3176B and 3196 engine
controller applications. The ECM can be moved from one application to another.
However, a password is required to activate the ECM when new software
¥ Same ECM used in is installed.
most 3406E
applications
The Personality Module contains the software with all the fuel setting
¥ Personality module information (such as horsepower, torque rise and air/fuel ratio rates)
contains software which determines how the engine will perform. The Personality Module
is wired into the ECM and no access panel is provided.

Flash Programming is the only method used to update the software on the
3406E. This method requires electronic reprogramming of the
Personality Module software.

¥ Upgrading personality Upgrading the software is not a routine task, but might be performed for
module software reasons of a product update, a performance improvement or a product
problem repair.

➥
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¥ ECM is sealed NOTE: The ECM is sealed and needs no routine adjustment or
maintenance. The Personality Module cannot be accessed other than
by Flash Programming. The ECM has an excellent record of
reliability. Therefore, any problems in the system are most likely to
be in the connectors and wiring harness. In other words, the ECM
should typically be the last item in troubleshooting.
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24

Fuel Injection

The 3400E EUI unit injector is electrically and mechanically similar to

¥ Unit injectors
the 3500 EUI electronic unit injector. The injector is controlled
¥ Electrically signalled, electrically by the ECM and is actuated mechanically. The signal from
mechanically actuated the ECM controls the opening and closing of the solenoid valve. The
solenoid valve controls the flow of high pressure fuel to the cylinder.
This system enables the ECM to control fuel volume and timing.
The 3400E injector has bar codes and numerical codes marked on the
¥ Injector codes
tappet. The numerical code must be entered into the ECM using ET. The
purpose of this code is to ensure that all injectors are matched as perfectly
as possible in performance, both in timing and fuel quantity.
If an injector is replaced, moved to another position on the engine, or if
two injectors are switched, then the injector codes must be reprogrammed.
¥ Programming injector The injector codes are programmed into the ECM using ET and the
codes
Calibrate Sensor Screen. Failure to enter the codes into a new ECM may
result in unequal timing and fuel delivery between cylinders.

WARNING

The injector solenoids operate on 105 Volts direct current. Always

remain clear of the injector area when the engine is running or
electrical shock may occur.
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EUI INJECTOR TESTING

METHODS

INJECTOR SOLENOID TEST

CYLINDER CUTOUT

AUTOMATIC INJECTOR TEST

25

Three tests can be used to determine which cylinder or injector is

malfunctioning:

INJECTOR SOLENOID TEST

¥ Injector testing
This test is performed while the engine is stopped. The injector solenoids
can be tested automatically with the service tool using the Injector
Solenoid Test. This function individually tests each solenoid in sequence
and indicates if a short or an open circuit is present.

CYLINDER CUTOUT (Manual test)

This test is performed while the engine is running at any speed.
The 105 Volt pulse can be individually cut out to aid in troubleshooting
misfire problems in the injector and the cylinder.

AUTOMATIC INJECTOR TEST

This test is performed with the service tool while the engine is running at
any speed. The test makes a comparative evaluation of all injectors and
numerically shows the results. The test enables an on-engine evaluation
of the injectors. (This test cannot be performed using the ECAP.)

When diagnosing a misfire problem, a satisfactory test of all injector

solenoids without any diagnostic messages indicates that a mechanical
problem in the cylinder probably exists. This problem could be caused by
a seized injector, a damaged inlet or exhaust valve.
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EUI CONTROL LOGIC

TIMING CONTROL
ENGINE SPEED TIMING DEGREES BTDC DESIRED
FUEL RPM TIMING FUEL INJECTION
FUEL QUANTITY BTDC CONVERT TIMING WAVE FORM
SELECT
TIMING DESIRED
TIMING
COOLANT COLD MODE
TEMPERATURE

26

Fuel Injection Control System

This diagram shows the timing control logic within the ECM.
¥ Fuel timing control

Engine speed and fuel quantity (which relates to load) input signals are
¥ Inputs to timing
control received by the timing control. The coolant temperature signal determines
when the Cold Mode should be activated. These combined input signals
determine the start of fuel injection.

¥ Benefits of a "smart" The timing control provides the optimum timing for all conditions. The
timing control
benefits of a "smart" timing control are:

- Reduced particulates and lower emissions

- Improved fuel consumption while still maintaining performance
- Extended engine life
- Improved cold starting
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3406E COOLANT
ELECTRONIC GOVERNOR SHUTDOWNS TEMPERATURE
SENSOR

ECM
ELECTRONIC
GOVERNOR
6
5 FUEL FRC TORQUE
SIGNALS ENGINE THROTTLE
INJECTION
TO FUEL 4 ENGINE RPM MAPS MAPS CONTROL
CONTROL
INJECTORS 3 LOGIC
2 TDC
1

SPEED/TIMING ENGINE RPM ENGINE RPM

SIGNAL

TURBO OUTLET AND

ATMOSPHERIC
TIMING PRESSURE SENSORS
WHEEL

SPEED/TIMING
SENSORS

27

Four input signals are used to control fuel quantity:

¥ Fuel quantity control
1. Engine speed
¥ Inputs to fuel quantity
2. Throttle position
control
3. Boost
4. Coolant temperature
These signals are received by the electronic governor portion of the ECM.
The governor then sends the desired fuel signal to the fuel injection and
injection actuation controls. The fuel quantity control logic also receives
signals from the fuel ratio and torque controls.
Two variables determine fuel quantity and timing:
- The start of injection determines engine timing.
¥ Start of injection
determines timing - The injection duration determines the quantity of fuel to be
injected.
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3406E (PASSIVE) SPEED/TIMING SENSORS

HIGH SPEED (UPPER)
SPEED/TIMING
SENSOR J44 P44
OR 1
BK 2

J1 P1

12 - HIGH SPEED S/T SENSOR

18 + HIGH SPEED S/T SENSOR
CRANKING (LOWER) TIMING CALIBRATION
SPEED/TIMING CONNECTOR ECM
SENSOR (3406E)
J20 P20 J26 P26
OR 1 2 723-PK 4 - CRANKING S/T/+TDC SENSORS
BK 2 1 724-PU 39 + CRANKING S/T/-TDC SENSORS

J2 P2

NOTE: P20/J26 POLARITY IS

TIMING CALIBRATION INTENTIONALLY REVERSED
PROBE

1 1 2
2 2 1

TIMING CALIBRATION
CABLE

28

¥ Speed/timing sensors Two Speed/Timing Sensors are installed in this 3406E: a high speed
(upper) and a cranking speed (lower) sensor. The Speed/Timing Sensors
serve four functions in the system:

¥ Four functions of the

1. Engine speed measurement
speed/timing sensor
2. Engine timing measurement
3. TDC location and cylinder number identification
4. Reverse rotation protection
The Speed/Timing Sensors, which are mounted on the rear of the front
¥ Sensor installation
housing, are installed with a clearance between the sensor and the timing
wheel. This clearance is not adjustable

NOTE: These sensors are not the same as those typically used on
¥ Passive sensors other EUI systems. They are the passive type which do not require a
require no power power supply. Furthermore, the high speed and cranking sensors are
supply
not interchangeable and each sensor has a different part number.
STMG 712 - 35 -
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TIMING WHEEL
TDC
TDC CYLINDER No. 1
REF 4 REF

CRANKING SPEED/TIMING
SENSOR EXTRA TOOTH
2
HIGH SPEED/TIMING
SENSOR
TDC

1 TIMING
CALIBRATION RANGE ± 4°
REF REF

TIMING WHEEL
ROTATION TDC
TDC
5

FIRING ORDER: 1 5 3 6 2 4

REF 3 REF

TDC

29

¥ High speed sensor The high speed (upper) Speed/Timing Sensor measures engine speed for
normal operations including governing and crankshaft position for timing
purposes and cylinder identification.

The cranking (lower) Speed/Timing Sensor is used during starting and

¥ Cranking speed allows continuous operation if the high speed sensor fails. A failure of the
sensor
high speed sensor will cause the ECM to automatically switch to the
cranking Speed/Timing Sensor. Also, the check engine lamp will turn
ON.
STMG 712 - 36 -
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30

¥ Timing wheel The Timing Wheel is a part of the drive gear for the camshaft. Timing
marks (arrow) are used to locate the wheel and the camshaft in the correct
¥ Timing marks (arrow)
position relative to the crankshaft which is pinned at TDC. This Timing
Wheel is used in all 3406E engines with passive Speed/Timing sensors.

¥ Tooth arrangement As previously stated, the Timing Wheel has a total of 25 teeth. One tooth
identifies TDC is positioned midway between the adjacent teeth. This configuration is
used by the ECM to locate TDC on the No. 1 cylinder (and subsequent
cylinders).

INSTRUCTOR NOTE: Reverse rotation protection is accomplished

¥ Sensor and tooth
by using the sequence in which the signals from the two sensors are
arrangements prevent
reverse rotation received by the ECM. The spacing between the two sensors on the
wheel is 90 degrees. If the interval between the signals is 270 degrees,
this information is interpreted by the ECM as reverse rotation. The
injectors will be disabled.
STMG 712 - 37 -
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31

¥ Speed/timing sensors The Speed/Timing Sensors are positioned horizontally on the engine, but
are positioned perpendicular to the timing wheel surface. In other words,
they face the side of the the timing wheel, similarly to the 3408/3412E
installation. However, the timing wheel is different as seen on the
previous page.

¥ Sensors generate a The teeth and sensors generate a signal which is converted by the ECM to
PWM signal from a Pulse Width Modulated (PWM) output signal for the purpose of timing
timing wheel teeth
and a frequency modulated output signal for speed measurement.

INSTRUCTOR NOTE: A description of PWM signals is provided

later in this presentation (Sensors and Systems).
STMG 712 - 38 -
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CRANKING
TIMING GEAR TOOTH TABLE
TABLE CRANKSHAFT CYLINDER
ENTRY ANGLE REFERENCE
A 30° NONE IDENTIFIED
B 30°
C 30°
D 30° HIGH
CRANKING
E 30° SPEED
SPEED CRANKSHAFT
F 30° SENSOR
SENSOR DEGREES
G 15°
H 15°
I 15°

30° 30° 30° 30° 30° 30° 15° 15° 15°

A B C D E F G H I

TIMING WHEEL ROTATION

32

¥ Cranking The Speed/Timing Sensors use the timing wheel with the teeth arranged
as shown to determine:
¥ Timing wheel teeth
and spacing
- Top Dead Center No. 1 (When found, the cylinders can be
identified.)

- Engine speed

The sequence of signals shown in the second column (duty cycle) is

analyzed by the ECM. At this point, no fuel will be injected until certain
conditions have been met.
STMG 712 - 39 -
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AFTER PATTERN RECOGNITION

TIMING GEAR TOOTH TABLE
TABLE CRANKSHAFT CYLINDER
ENTRY ANGLE REFERENCE
A 30° CYL NO 5 FIRING ORDER 153624
B 30°
C 30°
D 30° CYL NO 1
E 30°
F 30°
CRANKING HIGH
SPEED G 15° SPEED CRANKSHAFT
SENSOR H 15° SENSOR DEGREES
I 15°
TIMING WHEEL ROTATION

30° 30° 30° 30° 30° 30° 15° 15° 15°

A B C D E F G H I

CYL NO. 3 CYL NO. 5 CYL NO. 5 CYL NO. 1 CYL NO. 1
TDC REFERENCE TDC REFERENCE TDC
EDGE EDGE

33

¥ After pattern During start-up, the Cranking Speed Sensor initially monitors the pulses
recognition created by the passing teeth and identifies the sequence as shown. After a
complete rotation, the control can recognize the location of TDC from the
pattern in the above illustration.

During initial cranking, no fuel is injected until the following conditions

are met:

¥ Initial firing sequence The timing wheel has completed a full revolution.
TDC for all cylinders is identified by the control.
After the sensor has provided the necessary signals, the ECM is ready to
start injection.

NOTE: The reference points in the illustration are positions on the

timing wheel where the control measures the point of injection and
TDC.
STMG 712 - 40 -
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TIMING GEAR TOOTH TABLE

TABLE CRANKSHAFT CYLINDER
ENTRY ANGLE REFERENCE NORMAL OPERATION
A 30° CYL NO 5
B 30°
C 30°
D 30°
CRANKING E 30° CYL NO 1 HIGH
SPEED F 30° SPEED CRANKSHAFT
SENSOR G 15° SENSOR DEGREES
H 15°
I 15°
TIMING WHEEL ROTATION
30° 30° 30° 30° 30° 30° 15° 15° 15°

A B C D E F G H I

62° BTDC (EEPROM) 62° BTDC (EEPROM)

DES TIMING DES TIMING

DELAY NO. 5 DELAY NO. 1

INJECTION ASSUMED INJECTION
ASSUMED
TDC TDC
CYL NO. 3 CYL NO. 5 CYL NO. 5 CYL NO. 1 CYL NO. 1
TDC REFERENCE TDC REFERENCE TDC
EDGE (CALIBRATED) EDGE (CALIBRATED)

34

¥ Normal operation During normal operation, the ECM can determine timing from the
sequence reference point for each cylinder. The reference point is stored
by the ECM after calibration is performed.

Injection timing is calibrated by connecting a TDC probe to the service

¥ Signal pattern access connector on the engine harness, and by activating the calibration
identifies TDC sequence with the Caterpillar ET service tool. The ECM raises the engine
speed to 1100 rpm (to optimize measurement accuracy), compares the
¥ Conditions for
actual No. 1 TDC location to the assumed cylinder No. 1 TDC location,
injection
and saves the offset in the EEPROM (Electrically Erasable Programmable
Read Only Memory).

NOTE: The calibration offset range is limited to ± 4 crankshaft

degrees. If the range is exceeded, the offset is set to zero (no
calibration) and a calibration diagnostic message is generated.
STMG 712 - 41 -
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INJECTION CURRENT WAVEFORM

ONE CYCLE

PULL-IN PEAK CURRENT

CURRENT FLOW

HOLD-IN PEAK CURRENT

0 1 2 3 4 5
TIME (MILLISECONDS)

35

¥ Unit injector current This illustration shows how the current increases initially to pull in the
flow injection coil and close the poppet valve. Then, by rapidly chopping
(pulsing) the 105 Volts on and off, current flow is maintained. The end of
injection occurs when the current supply is cut; therefore, fuel pressure
drops rapidly in the injector.

INSTRUCTOR NOTE: This waveform may be demonstrated with a

131-4870 Scopemeter (or equivalent) and a current probe.
STMG 712 - 42 -
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FUEL SYSTEM LIMITS

• Maximum Horsepower
• Maximum Torque
• Fuel Ratio
• Cold Mode Limit
• Cranking Fuel Limit

36

System Controls

Just as mechanically controlled engines had mechanical limits to

determine maximum fuel delivery during full load, full torque and
acceleration, the EUI system also has electronic limits to protect the
engine. These limits are:

- Maximum Horsepower
¥ Fuel system limits
- Torque Limit (determines torque rise characteristics)
- Fuel Ratio Control (limits fuel until sufficient boost is available)
- Cold Mode Limit (limits fuel, controls white smoke when cold)
- Cranking Limit (limits fuel during cranking)
An acceleration delay during start-up holds the engine at LOW IDLE for
two seconds or until oil pressure reaches 140 kPa (20 psi).
STMG 712 - 43 -
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FUEL SYSTEM COLD MODES

• Speed Control
• Fuel Limiting
• Injection Timing
• Ether Injection

37

¥ Cold modes The EUI fuel system is designed to modify the operational characteristics
of the engine during cold operation. This modification is done to protect
the environment, the engine and to improve the operational characteristics
of the engine.

¥ Fuel system derates As the system limits fuel for every condition, derates are also built into
the system for protection. These derates are individually covered later in
the presentation, but are summarized here:

- Automatic Altitude Compensation (Altitude derate)

- Automatic Filter Compensation, derates for air filter restriction,

(not installed on Articulated Trucks)

- Engine Warning Derate, derates for low oil pressure and high
coolant temperature, (not installed on Articulated Trucks)

➥
STMG 712 - 44 -
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¥ Power correction If a loss of boost sensor output occurs, the ECM assumes zero boost
pressure. Although not strictly a derate, power is reduced by
approximately 50 to 60%.

- Fuel Temperature Compensation (Compensates up to 5% for

power loss caused by hot fuel)

NOTE: Fuel Temperature Compensation is not designed to correct

for excessive fuel overheating which could be caused by a variety of
reasons such as low fuel level combined with high ambient
temperature.

INSTRUCTOR NOTE: Discuss how these Cold Mode variations can

change the engine characteristics, particularly during diagnostic
operations. For example:

- Engine speed may be raised in Cold Mode.

- Engine power may be limited in Cold Mode.
- Engine fuel may be limited during cranking in Cold Mode.
STMG 712 - 45 -
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3406E SPEED/TIMING SENSOR CALIBRATION CIRCUIT

HIGH SPEED (UPPER)

SPEED/TIMING
SENSOR
J44 P44
OR 1
BK 2 P1 J1

12 - HIGH SPEED S/T SENSOR

18 + HIGH SPEED S/T SENSOR

TIMING CALIBRATION TIMING CALIBRATION ECM

PROBE CABLE (3406E)
P26
1 2 723-PK 4 - CRANKING S/T/+TDC SENSORS
2 1 724-PU 39 + CRANKING S/T/-TDC SENSORS

TIMING CALIBRATION P2 J2
CONNECTOR

CRANKING (LOWER)
SPEED/TIMING
SENSOR
J20 P20 J26
OR 1 2 NOTE: P20/J26 POLARITY IS
BK 2 1 INTENTIONALLY REVERSED

38

SYSTEM CALIBRATIONS

Speed/Timing Sensor Calibration

The Timing Calibration Probe (magnetic pickup) must be installed in the

¥ Timing calibration cylinder block for calibration.
sensor installation
The Timing Calibration Probe Cable is used to connect the probe to the
Timing Calibration Connector.
One end of the cable is connected to the Timing Calibration Probe. The
other end of the cable is connected to the P26 connector. The connector is
located above the ECM.
During calibration, the Timing Calibration Probe replaces the Cranking
Sensor in the circuit. Because the Cranking Sensor is disconnected during
calibration, only the upper (high speed) sensor is calibrated. Therefore,
both sensors must share the calibration data when the Cranking Sensor is
reconnected.
➥
STMG 712 - 46 -
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NOTE: For calibration, only the designated Timing Calibration

Connector (P26) just above the ECM can be used, not the
Speed/Timing Sensor Connector (P20) located at the front of the
engine.

As shown in the diagram, using the incorrect connector will cause the
wrong polarity and the wrong timing calibration value to be recorded
in the ECM. A timing error of approximately 4 degrees will result if
the wrong connector is used.
STMG 712 - 47 -
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TIMING CALIBRATION PROBE

INSTALLATION

TDC SLOT CRANKSHAFT

COUNTERWEIGHT

MACHINED FACE
DIRECTION OF
ROTATION

TIMING CALIBRATION ENGINE BLOCK

PROBE (SHOWN FROM REAR)

AIR GAP

39

¥ Timing calibration This view of the Timing Calibration Probe (magnetic pickup) shows how
probe installation and the air gap (clearance) is established between the probe and the face of the
adjustment crankshaft counterweight.

After top dead center (TDC) is located, rotate the engine clockwise
¥ Avoid damage to
approximately 60 degrees to prevent engaging the probe in the slot. The
probe
timing probe will be destroyed if the engine is rotated with the probe in
the slot. (The crankshaft is positioned at TDC initially to locate the
machined face on the counterweight.)

Insert the Timing Calibration Probe into the block until it touches the face
¥ Set probe clearance
of the crankshaft counterweight. Then, retract the probe 1 mm (.04 in.) to
provide a running clearance. A 2D6392 O-ring positioned on the probe
can be used to measure the clearance.

If the probe clearance is not set correctly, erratic performance or failure of

the timing calibration sequence can occur or the probe may be destroyed.

➥
STMG 712 - 48 -
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¥ Timing calibration Using ET, Timing Calibration is selected and the desired engine speed is
engine speed automatically set to 1100 rpm. (This speed varies between engines and is
automatically set
only specific to the 3406E.) This step is performed to prevent instability
and ensures that no backlash is present in the timing gears during the
calibration process.

Remove the calibration equipment, install the plug and connect all
harnesses. After the completing the procedure, the engine should be
retested to verify the correct operation. Active and logged fault screens
must also be checked.

NOTE: The 3406E engine in the D350/D400E Series II Articulated

Trucks has limited access in the flywheel housing for the 9S9082
Turning Tool. Therefore, the cab must be raised to gain access to the
timing pin and engine turning tool openings. (The TDC timing bolt is
also the turning tool upper access panel attachment bolt.)
STMG 712 - 49 -
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TIMING CALIBRATION

TIMING
WHEEL

REFERENCE EDGE TO TDC DISTANCE

REFERENCE
EDGE ASSUMED ACTUAL
CYL. NO. 1 TDC CYL. NO. 1 TDC

-4° +4°
±4° TIMING REFERENCE
TIMING CALIBRATION
OFFSET
SENSOR SIGNAL
(MAXIMUM RANGE
± 4 DEGREES)

25 ENGINE DEGREES

40

¥ Timing calibration The Speed/Timing Sensors use the timing wheel for a timing reference.
Timing calibration improves fuel injection accuracy by correcting for any
¥ Nulls small crankshaft slight tolerances between the crankshaft, timing gears, timing wheel and
to timing gear
Speed/Timing Sensor installations.
tolerances

During calibration, the offset is logged in the control module EEPROM

(Electrically Erasable Programmable Read Only Memory). The
calibration offset range is limited to ± 4 crankshaft degrees. If the timing
is out of range, calibration is aborted. The previous value will be retained
and a diagnostic message will be logged.

Timing calibration is normally performed after the following procedures:

1. ECM replacement
2. High Speed/Timing Sensor replacement
3. Timing Wheel replacement
STMG 712 - 50 -
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41

3406E Injector Calibration

The 3406E electronic unit injectors require calibration after installation or

after an ECM replacement. To access EUI Injector Calibration, use the
following pull down menu sequence:

Service / Calibrations / Injector Codes Calibration

¥ Injector calibration The purpose of Injector Calibration is to enable a more precise fuel flow
balances fuel flow balance between cylinders. The injectors are flow checked and calibrated
between cylinders
at the factory. Any minute fuel flow deviations are represented by a code
stamped on the top of the injector. These codes are programmed into the
ECM with the injector calibration function.
If for any reason injectors are changed or interchanged, calibration must
be performed for the affected injectors to avoid a power imbalance
between the cylinders.
INSTRUCTOR NOTE: A full description of this process is included
with the ET Self-Study Course. This course is included with the
current ET software CD ROM.
STMG 712 - 51 -
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42

Pressure Sensor Calibration

¥ Two methods to Two methods can be used to perform pressure sensor calibration: the key
calibrate pressure switch and the ET methods. Using the same calibration pulldown menu
sensors previously used, select the following pull down menu sequence:
Service / Calibrations / Pressure Sensor Calibration

The engine must not be running during Pressure Sensor calibration.

The atmospheric pressure sensor is used as the baseline to adjust the other
sensors. Other sensors with readings which do not agree with the
atmospheric sensor's output readings will be adjusted (within limits) to
agree with the atmospheric sensor.
Select Start or A to begin the sensor calibration.
¥ ET pressure sensor A diagnostic routine is built into the program which will identify a
calibration calibration problem. It could be that a sensor is out of the normal output
range for calibration. For example, the reason for calibration may be that
oil pressure reads +27.6 kPa (+4 psi) with the engine stopped. This
condition means that the oil pressure sensor absolute pressure reading is
130.9 kPa (19 psia) whereas the pressure at sea level is 119 kPa (14.7
psia).
As long as the error is within the calibration range, it will be corrected. If
not, a repair is necessary.
Once again, this process is more fully covered in the ET course. ➥
STMG 712 - 52 -
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INSTRUCTOR NOTE: This material will be reinforced if the

following ET tasks are demonstrated. Review the material with
questions following the tasks. The demonstration can be performed
on an engine, machine or a Training Aid with a laptop computer. The
suggested topics are:

Basic ET review (if required)

Status screens with throttle switch status, desired engine speed,
fuel position etc.
Active diagnostic codes
Logged diagnostic codes
Events screen
Configuration screen
Timing, injector and pressure sensor calibrations
Injector solenoid test
Cylinder cutout
Automatic injector test
This subject matter is covered in the ET training material which is
included with the current ET Dealer Additions CD ROM.
STMG 712 - 53 -
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FUEL SUPPLY SYSTEM

43

FUEL SUPPLY SYSTEM

Introduction

This portion of the presentation describes the operation of the EUI Fuel
Supply System as used on the 3406E engines in machine applications.

This description includes all components that transmit the fuel from the
tank and the primary filter to the injectors and return to the tank.
STMG 712 - 54 -
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FUEL GALLERY

EUI
EJECTORS

PRIMING PRESSURE
PUMP REGULATOR

ECM SECONDARY
FILTER FILTER BASE PRIMARY
(2 MICRON) FILTER
PRIMING PUMP TEMPERATURE
SENSOR RELIEF
CHECK VALVES VALVE
TRANSFER WATER
PUMP SEPARATOR

TANK

44

System Fuel Flow

Fuel is drawn from the tank through the primary filter by a gear-type
¥ Tracing the flow
transfer pump. The fuel then flows through the secondary fuel filter. The
through the fuel
supply system fuel is then directed through the Electronic Control Module (ECM)
housing fuel gallery for cooling purposes.
Next, the fuel enters the low pressure supply gallery located in the
cylinder head. Any excess fuel not injected leaves the cylinder head. The
flow then passes through the pressure regulating valve, which limits
pressure to 415 kPa (60 psi). Minimum pressure is 310 kPa (45 psi).
From the pressure regulating valve, the excess flow returns to the tank.
The ratio of fuel between combustion and fuel returned to the tank is
approximately 1:3 (i.e. four times the volume required for combustion is
supplied to the system for combustion and injector cooling purposes). A
fuel temperature sensor is installed in the filter base (shown above) to
compensate for power losses caused by varying fuel temperatures.
STMG 712 - 55 -
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45

¥ Primary fuel filter and Fuel is drawn from the tank through the Primary Filter (arrow). The
water separator Primary Fuel Filter contains a water separator which is a vital part of the
(arrow)
fuel system.

Any high pressure fuel system will deteriorate rapidly if water is allowed
¥ Water contamination
reduces injector life to circulate through the system. Water can cause early wear out or seizure
of the injectors due to a lack of lubricity and corrosion.

The normal expected fuel system life will not be achieved if

contaminated fuel is used. Use clean fuel and keep it clean.

The Primary Filter has a rating of 30 microns.

STMG 712 - 56 -
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2
1

46

1. Transfer pump The fuel flows from the Primary Filter, to the Transfer Pump (1) to the
Secondary Filter (2) partly hidden from view.
2. Secondary filter

The fuel transfer pump contains a bypass valve to protect the fuel system
¥ Bypass valve
components from excessive pressure. The bypass valve setting is higher
than the setting of the fuel pressure regulator (next view).

The fuel transfer pump is driven by the front gear train.

STMG 712 - 57 -
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47

¥ Secondary fuel filter Fuel flows from the Transfer Pump to the Secondary Fuel Filter shown
here. Return fuel from the injectors flows through the Fuel Pressure
Regulator in the Fuel Filter Base before returning to the fuel tank.

¥ Fuel pressure Fuel system pressure is controlled by the Fuel Pressure Regulator
regulator mounted in the Fuel Filter Base. This valve is set at 415 to 450 kPa
(60 to 65 psi).

The Fuel Pressure Regulator is positioned downstream of the injectors.

Fuel which passes through the valve is returned to the fuel tank.

Fuel pressure can be checked at the Fuel Pressure Regulator Valve by

removing a plug and connecting a gauge.

The Secondary Filter has a rating of 2 microns. It is vital to the life of the
injectors that the correct filter with the correct micron rating is used.

¥ Remote mounted NOTE: The Fuel Filter Base is remotely mounted (off the engine) on
secondary filter the D350E and D400E machines for improved accessibility.
STMG 712 - 58 -
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48

¥ ECM (arrow) Fuel flows from the Secondary Filter to the ECM (arrow) and then to the
front of the cylinder head and to the fuel injectors.

As in most applications, the ECM Fuel is cooled by fuel. This feature

prevents excessive heat coming from the injectors drivers from causing
damage.
STMG 712 - 59 -
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49

¥ Cylinder head fuel This view shows injectors, injector sleeves and the fuel supply passage.
supply passage A larger volume of fuel passes through the injector than is required for
injection and combustion. This extra flow is used to cool the injector
which is normally surrounded by hot coolant.

From the rear of the cylinder head, fuel flows to the return side of the
secondary filter base, which contains the Fuel Pressure Regulator.

From the Fuel Pressure Regulator, fuel returns to the tank.

STMG 712 - 60 -
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FUEL GALLERY

EUI
EJECTORS

PRIMING PRESSURE
PUMP REGULATOR

ECM SECONDARY
FILTER FILTER BASE PRIMARY
(2 MICRON) FILTER
PRIMING PUMP TEMPERATURE
SENSOR RELIEF
CHECK VALVES VALVE
TRANSFER WATER
PUMP SEPARATOR

TANK

50

¥ Chapter review INSTRUCTOR NOTE: To reinforce this presentation, the following

tasks may be demonstrated on an engine using the Service Manual
procedures:

Review the component functions using this slide.

Remove and install a unit injector.
Perform the necessary injector height adjustments.
Calibrate the injectors.
Prime the fuel system.
Using ET, perform Injector Solenoid and Cylinder Cutout Tests.
Check for active and logged faults.
STMG 712 - 61 -
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3406E EUI
SYSTEM POWER SUPPLIES

• ECM: 24 VOLTS
• INJECTORS: 105 VOLTS
• ANALOG SENSORS: 5 VOLTS
• DIGITAL SENSORS: 8 VOLTS

51

SYSTEM POWER SUPPLIES

Introduction

The EUI system has four power supplies with various voltages as shown.
¥ Four system power
supplies EXTERNAL POWER SUPPLY

ECM power supply 24 Volts

INTERNAL POWER SUPPLIES

Injector power supply 105 Volts

Analog Sensor power supply 5 Volts

Digital Sensor power supply 8 Volts

The power supplies are described in detail in the following section.

NOTE: This engine has no Speed/Timing Sensor power supply.

STMG 712 - 62 -
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3406E SYSTEM BLOCK DIAGRAM (D400E)

ECM POWER SUPPLY COMPONENTS

GROUND DISCONNECT SWITCH

MACHINE BOLT
CONNECTOR
24 V
UNSWITCHED POWER
ENGINE RETARDER SELECTOR SWITCH
15 AMP KEY
1
BREAKER MAIN SWITCH
2 LOW/MED/HIGH POWER
RELAY
3
MAIN POWER
4

3 MED THROTTLE SENSOR THROTTLE PEDAL

4 HIGH

GROUND LEVEL
SHUTDOWN SWITCH ENGINE RETARDER LAMP

STARTING AID SWITCH + BATTERY RELAY ETHER START VALVE

CAT MONITORING SYSTEM
CYLINDER
10
15
20
AUT P
ENGINE
5 25
X100
R
24 V 0 MPH
km/h
30 44

ET SERVICE TOOL
CAT AND ATA DATA LINK

52

ECM Power Supply

¥ 24 Volt power supply The power supply to the ECM and the system is provided by the 24 Volt
machine battery. The principle components in this circuit are:
¥ Power supply
components - Battery
- Key Start Switch
- Main Power Relay
- 15 Amp Breaker
- Ground Bolt
- ECM Connector (P1/JI)
- Machine Interface Connector (J3/P3)

If the supply voltage exceeds 32.5 Volts or is less than 9.0 Volts, a
diagnostic code is logged. (See the Troubleshooting Guide for complete
details on voltage event logging.)
STMG 712 - 63 -
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ECM POWER SUPPLY CIRCUIT

DISCONNECT ENGINE BLOCK

SWITCH GROUND BOLT
BATTERY
ECM (3406E)
P1 J1
(-)
24 VOLTS DC
229-BK-14 05 (-) BATTERY
(+) 15 A 1 150-OR-14 06 (+) BATTERY
CIRCUIT BREAKER
2 102-RD-16 04 UNSWITCHED PWR
P3 J3
10 AMP

C OFF
S ON
B ST

KEY SWITCH

53

¥ ECM power supply This schematic shows the principle components for a typical power
circuit supply circuit. Battery voltage is normally connected to the ECM.
However, an input from the key start switch turns the ECM on.

The machine wiring harness can be bypassed for troubleshooting

purposes. These steps are described in the Troubleshooting Procedure.

The supply Voltage may be checked using the ET Status Screen display.
STMG 712 - 64 -
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ECM CONNECTORS
40 PINS, WIRE SIDE
P2 P1
1 2 3 4 5 6 1 2 3 4 5 6

7 12 7 12

13 18 13 18

19 22 19 22

23 28 23 28

29 34 29 34

35 36 37 38 39 40 35 36 37 38 39 40

MACHINE INTERFACE CONNECTOR

40 PINS, WIRE SIDE
P3
1 2 3 4 5 6 7 8 9 10

11 15 16 20

21 25 26 30

31 32 33 34 35 36 37 38 39 40

54

Vital parts of all the power supplies (and sensor circuits) are the 40 pin
connectors.
¥ P1/P2 40 pin ECM This illustration shows the two ECM 40 pin connectors, P1 and P2,
connectors
looking from the harness side. The pins highlighted in the P1 connector
are for the ECM power supply circuit.

¥ J3 40 pin connector The slide also shows the P3 Machine Interface Connector. This 40 pin
connector transmits the power supply from the machine wiring to the
engine wiring harnesses.

The Troubleshooting Guide identifies the relevant pins for each circuit in
this manner. The P3 connector is identified in the same way and is a part
of the system power supply.
STMG 712 - 65 -
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INJECTOR WIRING SCHEMATIC

ECM
J91 P91 P2 J2 (3406E)
12 L983-WH 5 INJECTOR RETURN 1 & 2
10 L984-OR 17 INJECTOR RETURN 3 & 4
8 L985-YL 27 INJECTOR RETURN 5 & 6
6 A706-GY 34 INJECTOR 6 POWER
5 A705-BU 28 INJECTOR 5 POWER
4 A704-GN 22 INJECTOR 4 POWER
3 A703-BR 18 INJECTOR 3 POWER
2 A702-PU 12 INJECTOR 2 POWER
1 A701-GY 6 INJECTOR 1 POWER
11
9
7

55

Injector Power Supplies

The injectors are supplied with power from the ECM at 105 Volts. For
this reason, precautions must be observed when performing maintenance
around the valve covers.

If an open or a short occurs in the injector circuit, the ECM will disable
that injector. The ECM will periodically try to actuate that injector to
determine if the fault is still present and will disconnect or reconnect the
injector as appropriate.

NOTE: If an injector is replaced, it must be calibrated. Also if an

ECM is replaced and injector calibration is not performed, a fault
message will be generated.
STMG 712 - 66 -
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J21 P21 P2 J2
ECM (3406E EUI)
+V ANALOG A 36 +V ANALOG SUPPLY
ENGINE COOLANT ANALOG RETURN B 30 - ANALOG RETURN
TEMPERATURE SENSOR SIGNAL C

P22 J22
+V ANALOG A
ENGINE OIL ANALOG RETURN B
PRESSURE SENSOR SIGNAL C

P23 J23
+V ANALOG A
TURBO OUTLET ANALOG RETURN B
PRESSURE SENSOR SIGNAL C

TURBO INLET
P25 J25 ANALOG SENSOR
+V ANALOG A
PRESSURE SENSOR
(IF INSTALLED)
ANALOG RETURN
SIGNAL
B
C
POWER SUPPLY
P27 J27 5 ± 0.2 VOLTS
+V ANALOG A
ATMOSPHERIC ANALOG RETURN B
PRESSURE SENSOR SIGNAL C

P88 J88
+V ANALOG A
INLET AIR ANALOG RETURN B
TEMPERATURE SENSOR SIGNAL C

P43 J43
+V ANALOG A
FUEL TEMPERATURE ANALOG RETURN B
SENSOR SIGNAL C

56

Analog Sensor Power Supply

The Analog Sensor Power Supply provides power to all the analog
sensors (pressure and temperature sensors).

¥ Analog power supply The ECM supplies 5.0 ± 0.2 Volts DC (Analog Supply) through the J2/P2
connector to each sensor.

A power supply failure will cause all analog sensors to fail. This failure
could be caused by a short in a sensor or an open circuit in the common
lines close to the P2 J2 connector.

The Analog Sensor power supply is protected against short circuits. A

short in a sensor or a wiring harness will not cause damage to the ECM.

¥ Analog return NOTE: When checking the analog power supply voltage, always use
the analog return for the measurement and not the frame ground. A
difference can occur between the measurements of analog power
supply and system voltage. The analog power supply is held to close
tolerances.
STMG 712 - 67 -
11/99

DIGITAL SENSOR
POWER SUPPLY
8 ± 0.5 VOLTS

THROTTLE
POSITION SENSOR J35 P35 P1 J1 ECM (3406E EUI)
+V DIGITAL A 29 + V DIGITAL SUPPLY
DIGITAL RETURN B 35 - V DIGITAL RETURN
SIGNAL C

57

Digital Sensor Power Supply

¥ Digital power supply The ECM supplies power at 8 ± 0.5 Volts through the J1/P1 connector to
the Throttle Position Sensor circuit.

Like the Analog power supply, this circuit is protected against short
circuits, which means that a short in the sensor will not cause damage to
the ECM.

Some other 3406E applications may use this power supply to power, for
example, fan speed or exhaust temperature sensors.

¥ Digital power supply NOTE: It is necessary when checking this system power supply
voltage check Voltage to use the digital return for the measurement and not the
frame ground. A difference between these values can occur if an
incorrect ground is used.
➥
STMG 712 - 68 -
11/99

INSTRUCTOR NOTE: The following exercise will reinforce the

material introduced in the preceding slides and will allow questions to
be answered.

During this exercise, a demonstration on an engine or a Training Aid

should be performed showing:

Open circuit in the ECM power supply

Opens and shorts in the Analog and Digital power supplies
Status screen pressure and temperature readings with a fault in
the sensor power supply
STMG 712 - 69 -
11/99

ELECTRONIC SENSORS
AND
SYSTEMS

58

ELECTRONIC SENSORS AND SYSTEMS

Introduction

This section of the presentation covers the electronic sensors and related
circuits in the 3406E EUI fuel system.

Most of the diagrams used in this section are based on the D400E.
STMG 712 - 70 -
11/99

59

Speed/Timing Sensors

Two passive Speed/Timing Sensors are installed: a high speed and a

cranking (low speed) sensor. The Speed/Timing Sensors serve four basic
functions in the system:

¥ Four functions of the - Engine speed detection

speed/timing sensor
- Engine timing detection
- TDC and cylinder number identification
- Reverse rotation protection

The Speed/Timing Sensors are mounted on the rear of the front housing
below the timing gear wheel, and must be installed in accordance with the
Service Manual procedures.

This type of sensor (passive), unlike other Speed/Timing Sensors, has an

air gap. The sensor is not in direct contact with the timing wheel and runs
with a specified clearance.

¥ No power supply Additionally, these sensors do not require a power supply.

required for passive
speed/timing sensors
STMG 712 - 71 -
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SPEED/TIMING SENSORS

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR GROUND BOLT

MACHINE INTERFACE
CONNECTOR

60

¥ Speed/timing sensor If a high speed sensor failure occurs, the cranking speed sensor will
failure modes automatically provide the back-up. A momentary change of engine sound
will be noticed as the changeover occurs.

If the fault in the high speed sensor is corrected, the ECM will continue to
use the cranking speed sensor until the engine is shut down and restarted.
A subsequent Speed/Timing Sensor failure will cause an engine
shutdown.

The sensor may be functionally checked by cranking the engine and

observing the service tool status screen for engine rpm.

A failure of either sensor will be indicated by the active fault screen on

the service tool. An intermittent failure will be shown in the logged fault
screen.

Refer to the Service Manual for the correct installation procedure.

STMG 712 - 72 -
11/99

ANALOG SENSORS
Coolant temperature

Atmospheric pressure

Turbocharger outlet pressure

Lubrication oil pressure

Fuel temperature

Inlet air temperature

61

Analog Sensors and Circuits

The following analog sensors and circuits may be used in various

applications:

- Coolant Temperature Sensor

- Atmospheric Pressure Sensor
- Turbocharger Inlet Pressure Sensor
- Turbocharger Outlet (Boost) Sensor
- Lubrication Oil Pressure Sensor
- Fuel Temperature Sensor
- Inlet Air Temperature Sensor

NOTE: The Turbocharger Inlet Pressure Sensor is not used in the

D350E/D400E Series II Articulated Trucks.
STMG 712 - 73 -
11/99

COOLANT TEMPERATURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

62

¥ Coolant temperature The Coolant Temperature Sensor supplies the temperature signal for the
sensor following functions:

- Caterpillar Monitoring System

- Demand Control Fan (if equipped)
- ET or ECAP coolant temperature display
- High coolant temperature event logged above 107¡C (225¡F)
- Engine Warning Derate when 107¡C (225¡F) is exceeded or
low oil pressure occurs (if equipped)
- Temperature sensor for ether aid operation

NOTE: All the analog sensors share the common analog power
supply of 5.0 ± 0.2 Volts.
STMG 712 - 74 -
11/99

FUEL TEMPERATURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)

63

¥ Fuel temperature The ECM uses fuel temperature measurement to make corrections to the
sensor fuel rate to maintain power regardless of fuel temperature (within certain
parameters). This feature is called "Fuel Temperature Compensation."
¥ Enables fuel
temperature
compensation The sensor output should be between 0.4 and 4.6 Volts.
STMG 712 - 75 -
11/99

INLET AIR TEMPERATURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)
INLET AIR TEMPERATURE SENSOR

64

¥ Inlet air temperature The Inlet Air Temperature Sensor is used by the ECM to prevent
sensor excessive inlet temperatures from damaging the engine.

High inlet air temperature leads to high exhaust temperatures which can
cause damage to exhaust components (such as turbochargers and exhaust
valves).
STMG 712 - 76 -
11/99

ATMOSPHERIC PRESSURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR
GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)
INLET AIR TEMPERATURE SENSOR

ATMOSPHERIC PRESSURE SENSOR

65

¥ Atmospheric pressure All pressure sensors in the system measure absolute pressure and,
sensor therefore, require the atmospheric sensor to calculate gauge pressure. The
sensors are used both individually (absolute pressure) in the case of
¥ Used to calculate atmospheric pressure, and as a pair to calculate oil and boost pressures
gauge pressure (gauge pressures).

¥ Two methods used to All the pressure sensor outputs are matched to the Atmospheric Pressure
calibrate sensors Sensor output during calibration. Calibration can be accomplished using
the ET service tool or by turning on the key start switch without starting
the engine for five seconds to automatically calibrate the sensors. The
Atmospheric Pressure Sensor performs four main functions:

¥ Four main functions 1. Automatic Altitude Compensation (maximum derate 24%)

2. Automatic Filter Compensation (maximum derate 20%) if
equipped
3. Part of pressure calculation for gauge pressure readings
4. Reference sensor for pressure sensor calibration
STMG 712 - 77 -
11/99

ENGINE POWER DERATING MAP

ACCORDING TO ATMOSPHERIC PRESSURE
100% 7,500

98% 8,210
PERCENT OF FULL LOAD POWER

96% 8,920

94% 9,630

92% 10,340

ALTITUDE IN FEET
90% 11,050

88% 11,760

86% 12,470

84% 13,180

82% 13,890

80% 14,600

78% 15,310

76% 16,020

74% 16,730

72% 17,440

77 76 75 74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53

ATMOSPHERIC PRESSURE IN kPa

66

¥ Automatic altitude Atmospheric pressure measurement by the sensor provides an altitude

compensation reference for the purpose of Automatic Altitude Compensation.
The graph shown here describes how derating on a typical 3406E starts at
7500 ft. and continues linearly to a maximum of 17000 ft. Other 3406E
engines may start as low as 4000 ft. depending on the application.
The advantage of the EUI system is that the engine always operates at the
¥ System continually
correct derating setting at all altitudes. The system continually adjusts to
adjusts to optimum
power setting the optimum setting regardless of altitude, so the engine will not exhibit a
lack of power or have smoke problems during climbs or descents to
different altitudes.
NOTE: The EUI system has an advantage over a mechanical fuel
system which is derated in "altitude blocks" (i.e. 7500 ft., 10000 ft.,
12500 ft.). EUI derating is continuous and automatic. Therefore, a
machine operating in the lower half of the block is not penalized with
low power. Conversely, a machine operating in the upper half of the
block will not overfuel with the EUI system.
STMG 712 - 78 -
11/99

OIL PRESSURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR
GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)
INLET AIR TEMPERATURE SENSOR
OIL PRESSURE SENSOR
ATMOSPHERIC PRESSURE SENSOR

67

¥ Oil pressure Two pressure sensors are used for the measurement of oil (gauge)
pressure:

- Oil Pressure Sensor

- Atmospheric Pressure Sensor

PRESSURE CALCULATIONS
¥ Calculations are used MEASUREMENT MEASURED BY RESULT
to determine gauge
pressure
Oil pressure [oil press (A) - atmospheric (A)] = oil pressure (GP)

These measurements are used to determine oil pressure for the ET service
tool, Caterpillar Monitoring System and to alert the operator that an
abnormal condition exists. The sensor operating range is 0 to 690 kPa
(0 to 100 psi) (A).

NOTE: (A) = absolute pressure

(GP) = gauge pressure
STMG 712 - 79 -
11/99

OIL PRESSURE MAP

340 49.3

320 46.4

300 43.5

280 40.6
OIL PRESSURE IN kPa

OIL PRESSURE IN PSI

260 37.7

240 34.8

220 31.9

200 29

180 26.1

160 23.2

140 20.3

120 17.4

100 14.5

80 11.6

60 8.7
600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
ENGINE RPM
kPa x 0.145 = PSI

68

¥ Oil pressure map Engine oil pressure varies with engine speed. As long as oil pressure
increases above the upper line after the engine has been started and is
¥ Determines correct running at low idle, the ECM reads adequate oil pressure. No faults are
pressure for all rpm indicated and no logged event is generated.

If the engine oil pressure decreases below the lower line, the following
occurs:

¥ Low oil pressure

- An event is generated and logged in the permanent ECM memory.
indications - A Category 3 Warning (alert indicator, action lamp and alarm) is
generated on the Caterpillar Monitoring System (if so equipped).
- The engine is derated (if so equipped) to alert the operator.
The two lines are sufficiently separated to prevent multiple alarms and
events or a flickering lamp. This pressure separation is referred to as
"hysteresis."
STMG 712 - 80 -
11/99

TURBOCHARGER OUTLET PRESSURE SENSOR

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR
GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

FUEL TEMP SENSOR EXTENSION TO REMOTE

FILTER (D400E)
INLET AIR TEMPERATURE SENSOR
OIL PRESSURE SENSOR
ATMOSPHERIC PRESSURE SENSOR

TURBO OUTLET PRESSURE SENSOR

69

¥ Turbo outlet pressure The Turbocharger Outlet Pressure Sensor measures absolute pressure
sensor downstream of the aftercooler. Boost (gauge) pressure can be read with
the service tools. This measurement is a calculation using the
¥ Boost pressure
calculation Atmospheric Pressure and the Turbocharger Outlet Pressure Sensors.
A failure of this sensor can cause the ECM to reduce power by as much as
60% when the ECM defaults to a zero boost condition.
The primary function of the sensor is to enable the Air/Fuel Ratio Control
which reduces smoke, emissions and maintains engine response during
¥ Air/fuel ratio control
acceleration. The system utilizes boost pressure, atmospheric pressure
and engine speed to control the air/fuel ratio. Engine fuel delivery is
limited according to a map of gauge turbo outlet (boost) pressure and
engine speed. The Air/Fuel Ratio Control setting is not adjustable in
3406E machine applications.
INSTRUCTOR NOTE: The pressure calculations and purposes of
these calculations for all sensors are tabulated on the next page.

➥
STMG 712 - 81 -
11/99

PRESSURE CALCULATIONS

MEASUREMENT MEASURED BY RESULT

¥ Calculations 1. Atmospheric pressure atmospheric sensor = ambient press (absolute)

determine gauge
pressure 2. Air filter differential Atmospheric - turbo inlet = filter ∆ pressure

3. Boost turbo outlet - atmospheric = boost (gauge press)

4. Manifold press. absolute turbo outlet sensor = boost (absolute press)

5. Oil pressure oil press - atmospheric = oil press (gauge press)

These measurements are used to determine:

1. Automatic Altitude Compensation

2. Automatic Air Filter Compensation and Restriction Indication

(if so equipped)

3. ET Boost Measurement

4. Caterpillar Monitoring System Oil Pressure Indication

(Lubrication)

5. Altitude

NOTE: ∆ pressure = differential pressure

STMG 712 - 82 -
11/99

DIGITAL SENSORS AND CIRCUITS

• Throttle Position Sensor

70

Digital Sensors and Circuits

The following digital sensors and circuits are used in the 3406E fuel
system:

- Throttle Position Sensor

- Speed/Timing Sensors (covered separately)
STMG 712 - 83 -
11/99

ENGINE SPEED CONTROL SYSTEM COMPONENTS

GROUND DISCONNECT SWITCH
BOLT
MACHINE INTERFACE CONNECTOR

24 V
UNSWITCHED POWER
ENGINE RETARDER SELECTOR SWITCH
1 15 AMP KEY
MAIN SWITCH
BREAKER
2 LOW/MED/HIGH POWER
3
RELAY
4
MAIN POWER

2
3 THROTTLE SENSOR THROTTLE PEDAL
4

GROUND LEVEL
SHUTDOWN SWITCH ENGINE RETARDER LAMP

STARTING AID SWITCH + BATTERY RELAY ETHER START VALVE

CAT MONITORING SYSTEM
CYLINDER
ENGINE
15 AUT P
10 20
5
25
X100
R 0 MPH 30
44
24 V km/h

ET SERVICE TOOL
CAT AND ATA DATA LINK

71

¥ Throttle position The Throttle Position Sensor provides engine speed control for the
sensor operator.

At engine start-up, the engine rpm is set to LOW IDLE for two seconds to
allow an increase of oil pressure before the engine is accelerated.

The Throttle Position Sensor receives 8 Volts from the Digital Sensor
¥ 8-Volt digital sensor
Power Supply at the ECM.
power supply
A functional check of the throttle control system can be performed by
¥ Throttle functional
connecting ET and monitoring the throttle position on the status screen as
check
the throttle is moved slowly in both directions. The status screen will
show between 0 and 100% of throttle position. (This reading should not
be confused with the duty cycle percentage.) Also a check of the Active
Faults screen will verify the status of the circuit.

A failure of this circuit will allow the engine to run at LOW IDLE only.

NOTE: This system eliminates all mechanical linkage between the

operator's engine speed controls and the governor (ECM).
STMG 712 - 84 -
11/99

PULSE WIDTH MODULATED SIGNALS

10%
ON

DUTY = 10%
CYCLE

OFF

50%
ON

DUTY = 50%
CYCLE

OFF
1 CYCLE
90%
ON

DUTY = 90%
CYCLE

OFF
DUTY CYCLE = PERCENT OF TIME ON VS PERCENT OF TIME OFF

72

¥ Throttle position A Pulse Width Modulated (PWM) signal output is sent from the Throttle
sensor signal Position Sensor to the ECM. A PWM signal eliminates the possibility of
an erroneous throttle signal due to a short causing a possible "run-away."
¥ Control defaults to If a signal problem occurs, the control defaults to a desired engine speed
low idle
of low idle. If the ECM detects an out-of-normal range signal, the ECM
ignores the Throttle Position Sensor signal and defaults to LOW IDLE.
The sensor output is a constant frequency Pulse Width Modulated (PWM)
signal to the ECM. For example, the D400E Articulated Dump Truck
sensor produces a duty cycle of 10 to 22% at the low idle position and 75
to 90% at the high idle position. The duty cycle can be read by the ECAP
Service Tool and some digital multimeters. The percent of duty cycle is
translated into a throttle position of 0 to 100% by the ECM, which can be
read on the ET status screen. Other applications differ in PWM values for
low and high idle. These values can be seen in the Troubleshooting Guide
for the appropriate application.
NOTE: Percentage of duty cycle and throttle position percentage are
different and should not be confused.
STMG 712 - 85 -
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GROUND LEVEL SHUTDOWN SWITCH CIRCUIT

ECM (3406E EUI)

GROUND LEVEL
SHUTDOWN SWITCH P1 J1
1
2 GND LVL SHUTDOWN (NO)
2
8 GND LVL SHUTDOWN (NC)
3 DIGITAL RETURN
29

73

Engine Shutdown Systems

The switch signals the ECM to cut electrical power to the injectors, but
¥ Ground level
shutdown switch
maintains power to the ECM. This feature also enables the engine to be
cranked without starting for maintenance purposes.

The Ground Level Shutdown Switch is connected to the ECM through the
machine and engine wiring harnesses. No other circuits may be
connected to this system. The User Defined Shutdown may be used in
conjunction with other circuits.

The circuit works by grounding either of two wires. By reversing the

status of these wires, the engine will either run or be shut down. If the
switch is operated, it is necessary to turn the key start switch off for at
least five seconds before attempting to restart. Otherwise, the engine will
¥ Turn key switch off crank but not start.
before restarting
This feature is installed on D350E/D400E; however, not all machines
have this feature.
STMG 712 - 86 -
11/99

USER DEFINED SHUTDOWN CIRCUIT

ECM (3406E EUI)

J3 P2 J2

USER SHUTDOWN 12 1 USER SHUTDOWN

DEVICE

74

¥ User defined The User Defined Shutdown feature (if installed) may be used to connect
shutdown input another device to the system to shut down the engine (such as a customer
installed fire suppression system). When the shutdown input is grounded
for one second, the engine will stop running. The input must be pulled
down below 0.5 Volts before the ECM will recognize the shutdown signal.

Operation of the User Defined Shutdown is logged as an event and can be

shown on the ET status screen.

When installed on a D400E Articulated Dump Truck, this feature is

¥ Safety feature
programmed to function only during the following conditions for safety
reasons:

- Parking brake is ENGAGED

- Transmission is in NEUTRAL
- Machine ground speed is at zero

Other machines may not have this feature installed.

STMG 712 - 87 -
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ETHER INJECTION SYSTEM ECM (3406E)

P2 J2

ETHER SWITCH J3 P3 P1 J1

9 998-BR 29 DIGITAL RETURN

38 25 ETHER SWITCH
720-GY
21 710-BR 40 ETHER ON

+ P37 J37 FROM

1
CYLINDER
2
+24V
RELAY
ETHER
START VALVE TO ENGINE

75

Ether Injection System

The ECM controls the use of ether for cold starting. The ECM uses inputs
from the Speed/Timing and Coolant Temperature Sensors to determine the
need for ether.

The ECM cycles the ether for three seconds on and three seconds off.
¥ Ether injection Actual flow is determined by engine speed and temperature. Automatic
parameters ether injection is injected when the coolant temperature is below 0¡C
(32¡F) and engine speed is below 500 rpm.

A Manual Mode allows ether injection when the coolant temperature is

below 10¡C (50¡F) and engine speed is below 1200 rpm. In the Manual
Mode, a precise quantity of ether is injected. The ether injection status
can be read on the ET status screen.
STMG 712 - 88 -
11/99

SERVICE CAT DATA LINK

TOOL
CONNECTOR
ADEM II
ELECTRONIC
CONTROL LAPTOP
COMPUTER
MODULE
(ECM) CONTROL SERVICE TOOL

CAT
ELECTRONIC TECHNICIAN
7X1701
COMMUNICATION
ADAPTER

15 AUT P
10 20
5
25
X100
R 44
TRANSMISSION 24 V
0 MPH
km/h
30

ELECTRONIC
CONTROL
MODULE

CATERPILLAR MONITORING SYSTEM

DISPLAY UNIT

76

CAT Data Link

¥ CAT Data Link The CAT Data Link is the communication link between the ECM,
transmission control, Caterpillar Monitoring System, ET Service Tool, PC
¥ Link between various based software and other onboard/offboard microprocessor based systems.
systems The CAT Data Link allows the various onboard systems to communicate
through a two wire connection. Up to 10 systems can be connected on a
machine.

The CAT Data Link is used for programming and troubleshooting the
electronic modules used with Caterpillar service tools through the Service
¥ Service tool Tool Connector. The ET Service Tool is connected through the Service
connector Tool Connector.

If a Personality Module is not installed in the ECM, the service tool will
not be able to communicate with the ECM.
STMG 712 - 89 -
11/99

CAT DATA LINK CIRCUIT

TRANSMISSION CONTROL CATERPILLAR

MODULE MONITORING SYSTEM

Cat Data Link + 9 5 Cat Data Link +

Cat Data Link - 3 14 Cat Data Link -

ENGINE ECM

J42 P3 J3 P1 J1
D 7 893-GN 9 Cat Data Link +
E 6 892-BR 3 Cat Data Link -
SERVICE TOOL
H 31 E794-YL 7 ATA Data Link +
CONNECTOR
J 32 E-793-BU 1 ATA Data Link -
MACHINE INTERFACE
CONNECTOR

77

¥ Data link wires twisted The CAT Data Link is a two wire (twisted pair) electrical connection used
to reduce RFI for communication between electronic modules that use the CAT Data
Link. The cables are twisted to reduce RFI (Radio Frequency
Interference).

Typical systems connected by the data link are:

- ECM
- Caterpillar Monitoring System Modules
- Caterpillar ET Service Tools
- Transmission Control Module
The ECM communicates with the Caterpillar Monitoring System to share
engine information such as engine speed, engine oil pressure, coolant
temperature, filter restriction, and electronic system faults.

¥ Two data link systems Two Data Link systems are used. The CAT Data Link circuit is used for
normal diagnostic and programming functions, and the ATA Data Link is
used for flash programming.
STMG 712 - 90 -
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LOGGED EVENTS
• High coolant temperature
• Loss of coolant flow
• Low (lube) oil pressure
• User defined shutdown
• Air inlet restriction
• Engine overspeed

78

Logged Events

¥ Logged events
Logged events as listed on the appropriate ET screen are conditions which
are abnormal to the operation of the engine (for example: high
temperature, low pressure or excessive engine speed). These conditions
would not normally be caused by an electronic problem.

Some of the parameters listed in this presentation are used in the ET

events list. They are:

- High coolant temperature above 107¡C (225¡F)

¥ Event list - Loss of coolant flow (if installed)
- Low (lubrication) oil pressure (according to the oil pressure map)
- User defined shutdown (if installed)
- Air inlet restriction (if installed)
- Engine overspeed histogram
All the parameters listed (except engine overspeed) can be read on the ET
status screens. Overspeed can be read on the Status Flag Indicator.

Events are not logged if an electronic fault is detected.

Passwords are required to clear events. This process would normally be

performed during an engine overhaul. At other times, the events would
be left as a record of the engine history prior to overhaul time.
STMG 712 - 91 -
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CATERPILLAR MONITORING SYSTEM

P
15 AUT

10 20

5
25
X100
R
24 V
0 MPH 30 44
km/h

79

Caterpillar Monitoring System

¥ Caterpillar monitoring The Caterpillar Monitoring System is used on various Caterpillar

system
machines. It has a similar look to the Vital Information Management
System (VIMS) and includes the following:

- Message Center Module

- Speedometer/Tachometer Module
- Four Gauge Cluster Module
- Action Lamp and Action Alarm

This system receives information over the CAT Data Link. The display
components show the operator the condition of machine systems and
system diagnostic information.
STMG 712 - 92 -
11/99

80

Conclusion

The Caterpillar EUI Engine control is a sophisticated system. However,

like many modern electronic controls, it is easier to service than previous
pump and line systems.

INSTRUCTOR NOTE: To reinforce this presentation, review the

various sensor and component functions.

The following tasks can be demonstrated:

Opens and shorts in analog and digital sensors

Status screens with pressure and temperature readings
Check switch status for all system switches
Opens and shorts in throttle sensor (check operation with ET)
Identify connectors, trace sensor circuits and perform continuity
checks
Check for active and logged faults
Check events and overspeed histogram
STMG 712 - 93 -
11/99

SLIDE LIST
1. Title slide 41. Injector calibration
2. Engine overview 42. Pressure sensor calibration
3. Fuel delivery system 43. Fuel supply system, text
4. Major components 44. Fuel delivery system
5. Engine view 45. Primary fuel filter and water separator
6. Engine view 46. Transfer pump
7. Secondary fuel filter 47. Secondary fuel filter
8. Coolant temperature sensor 48. ECM cooling lines
9. Atmospheric pressure sensor 49. Cylinder head fuel passages
10. Turbocharger pressure sensor 50. Fuel delivery system, review
11. Machine interface connector 51. System power supplies, text
12. Injector connector 52. ECM power supply
13. Oil pressure sensor 53. ECM power supply circuit
14. Aftercooler temperature sensor 54. ECM power connectors
15. Timing calibration sensor 55. Injector wiring schematic
16. Timing calibration sensor installation 56. Analog power supply
17. Throttle position sensor 57. Digital power supply
18. Ground level shutdown switch 58. Electronic sensors and systems
19. Service tool connector 59. Speed timing sensors
20. Engine mounted components diagram 60. Speed timing sensor diagram
21. Machine mounted components diagram 61. Analog sensors, text
22. Electronic control system, text 62. Coolant temperature sensor
23. ECM 63. Fuel temperature sensor
24. Unit injector 64. Inlet air temperature sensor
25. EUI injector testing methods, text 65. Atmospheric pressure sensor
26. EUI control logic 66. Engine power derating map
27. Fuel quantity control 67. Oil pressure sensor
28. Speed timing sensors 68. Oil pressure map
29. Timing wheel diagram 69. Turbocharger outlet pressure sensor
30. Timing wheel 70. Digital sensors and circuits
31. Speed timing sensors 71. Throttle position sensor
32. Cranking 72. Pulse width modulated signals
33. After pattern recognition 73. Ground level shutdown switch circuit
34. Normal operation 74. User defined shutdown circuit
35. Injection current waveform 75. Ether injection system
36. Fuel system limits, text 76. Cat data link
37. Fuel system cold modes, text 77. Cat data link circuit
38. Timing calibration circuit 78. Logged events, text
39. Timing calibration sensor adjustment 79. Caterpillar monitoring system
40. Timing calibration 80. Conclusion
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STMG 712
FUEL GALLERY

EUI
EJECTORS

PRIMING PRESSURE
PUMP REGULATOR

- 94 -
ECM SECONDARY
FILTER FILTER BASE PRIMARY
(2 MICRON) FILTER
PRIMING PUMP TEMPERATURE
SENSOR RELIEF

Serviceman's Handout No. 1

CHECK VALVES VALVE
TRANSFER WATER
PUMP SEPARATOR

TANK
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STMG 712
3406E ENGINE SYSTEM BLOCK DIAGRAM (D400E)
ENGINE MOUNTED COMPONENTS

6 DRIVERS
ENGINE
HARNESS

3 RETURNS

J2
ENGINE RETARDER
SOLENOIDS ECM
J1

- 95 -
HIGH SPEED/TIMING SENSOR

CRANKING TIMING CALIBRATION

SPEED/TIMING SENSOR CONNECTOR
GROUND BOLT
COOLANT TEMPERATURE SENSOR
MACHINE INTERFACE
CONNECTOR

Serviceman's Handout No. 2

FUEL TEMP SENSOR EXTENSION TO REMOTE
FILTER (D400E)
INLET AIR TEMPERATURE SENSOR
OIL PRESSURE SENSOR
ATMOSPHERIC PRESSURE SENSOR

TURBO OUTLET PRESSURE SENSOR

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STMG 712
3406E SYSTEM BLOCK DIAGRAM (D400E)
MACHINE MOUNTED COMPONENTS

GROUND DISCONNECT SWITCH

BOLT
MACHINE INTERFACE CONNECTOR

24 V
UNSWITCHED POWER
ENGINE RETARDER SELECTOR SWITCH
1 15 AMP KEY
BREAKER MAIN SWITCH
2 LOW/MED/HIGH POWER
RELAY
3
4
MAIN POWER

- 96 -
1

2
3 MED THROTTLE SENSOR THROTTLE PEDAL
4 HIGH

GROUND LEVEL
SHUTDOWN SWITCH
ENGINE RETARDER LAMP

Serviceman's Handout No. 3

STARTING AID SWITCH + BATTERY RELAY ETHER START VALVE
CAT MONITORING SYSTEM
CYLINDER

10
15
20
AUT P ENGINE
5 25
R X100
MPH 44
0 km/h 30
24 V

ET SERVICE TOOL
CAT AND ATA DATA LINK
STMG 712 - 97 -
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INSTRUCTOR NOTES
STMG 712 - 98 -
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INSTRUCTOR NOTES
STMG 712 - 99 -
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INSTRUCTOR NOTES
SESV1712 Printed in U.S.A.
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