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777D
Service TrainingMALAGA
ELECT. ENG. CONTROL
ThorbenMARCH 1998
IV. 3500B EUI
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CHAPTER : 3500B
AIR INTAKE AND EXHAUST
ELECT. ENG. CONTROL
2Page:
This sectional view of the engine shows the injector installation and the pushrod arrangement in
relation to the upper portion of the engine.
This sectional view is similar to the original 3500 EUI engine. Major differences are the spring
loaded injector push rods and the larger diameter camshaft.
Each cylinder has three corresponding camshaft lobes. The center lobe is is used to actuate the
unit injector. The 3500B has a larger diameter camshaft to accommodate the higher injection
pressures generated in the unit injector pumps.
The cylinder block has a larger camshaft bore to accommodate the larger camshaft. (All 3500
engines are now being manufactured to this standard.)
The 3500B injector pushrod spring, which maintains contact between the lifter roller and the
camshaft lobe. This spring is designed to maintain cam follower and camshaft contact andprotect the mechanism during a possible overspeed
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CHAPTER : 3500B
CYLINDER HEADS
ELECT. ENG. CONTROL
3Page:
MUI EUI
This picture shows the difference between the Mechanical Unit Injection (MUI) and current Electronic
Unit Injection (EUI) installation in the cylinder head.
Notice the Helper Spring on the injector pushrod. This arrangement is designed to keep the follower in
constant contact with the camshaft. The helper spring is required due to the increased injection pressures
of 151 MPa (22000 psi) and the steeper, high lift camshaft lobe profile.
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4
P a g e:
FUELTANK
PRIMARYFUEL
FILTER
FUEL
PRESSUREREGULATOR
FUELTRANSFER
PUMP
ECM
CYLINDERHEAD
PRIMING PUMP SUPPLY
DIFFERENTIALPRESSURE
SWITCH
RETURN FUEL
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CHAPTER : 3500B
FUEL SUPPLY SYSTEM
ELECT. ENG. CONTROL
5Page:
PRIMARYFILTER
TRANSFERPUMP
SECONDARYFILTER
FUEL TANK
ECM
FUEL TANK
FUELPRESSURE
REGULATOR
This view shows the injector and its fuel supply circuit. A larger volume of fuel passes through the
injector than is required for injection. This extra flow is used to cool the injector, which is also
surrounded by coolant.
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CHAPTER : 3500B
COMPONENT DIAGRAM - 777D
ELECT. ENG. CONTROL
6Page:
T O
P R E L U B R I C A T I O N
P U M P
+ B A T T E R Y G
R O
U N D
B O
L T
1 5 A M P
B R E A K E R
K E Y S T A R
T
S W I T C H
2 4 V
P 2 0 / J 2 0
S P E E D / T I M I N G
S E N S O R
J 3 / P 3 M A C H I N E
I N T E R F A C E
C O N N E C T O R
C O O L A N T
T E M P E R A T U
R E
S E N S O R
8 / 1 2 / 1 6
I N J E C T O R S
G R O
U N D B O L T
P 2 6 T / C
C O N N E C T O R
J 4 / P 4 T H R O U G H
J 1 9 / P 1 9
J 2
J 1
E C M
U N F I L T E R E D O I L
P R E S S U R E
S E N S O R
A F T E R C O O L E
R
T E M P E R A T U R
E
S E N S O R
C R A N K C A S E
P R E S S U R E
S E N S O R
J
2 9 / P 2 9
R I G H T
T U R B O C H A R G E R
I N L E T P R E S S U R E
S E N S O R
J
2 5 / P 2 5
L O W O
I L
L E V E L
S W I T C H
A T M O S P H E R I C
P R E S S U R E
S E N S O R
F U E L F I L T E
R
D I F F E R E N T I A L
P R E S S U R E S W
I T C H
T U R B O C H A R G E R
O U T L E T
P R E S S U R E S E N S O R
J
2 3 / P 2 3
C O O L A N T
F L O W
S W I T C H
F I L T E R E D O I L
P R E S S U R E
S E N S O R
J 2 2 / P 2 2
L E F T
T U R B O C H A R G
E R
E X H A U S T
T E M P E R A T U R E
S E N S O R
R I G H T
T U R B O C H A R G
E R
E X H A U S T
T E M P E R A T U R E
S E N S O R
L E F T
T U R B O C H A R G E R
I N L E T P R E S S U R E
S E N S O R
J 2 8 / P 2 8
J 3 5 / P 3 5
T H R O T T L E
P O S I T I O N
S E N S O R
T H R O T T L E
B A C K - U P
S W I T C H
U S E R D E F I N E D S H U T D O W
N
G R O U N D
L E V E L
S H U T D O W
N
S W I T C H
B A T T E R Y
E N G I N E F A N
C O N T R O
L
S O L E N O I
D
A / C
O N
S W I T
C H
F A N S P E E D S E N S O R
+ B A T T E R Y
R E L A Y
C Y L I N D
E R
E N G I N E
E T H E R S T A R T V A L V E
S T A R T I N G
A I D S W I T C H
J 2 1 / P 2 1
J 3 2 / P 3 2
J 1 0 5 / P 1 0 5
J 1 0 6 / P 1 0 6
J 4 7 / P 4 7
P 3 0 / J 3 0
J 2 7 / P 2 7
J 4 8 / P 4 8
P 8 4 / J 8 4
P 4 1 / J 4 1
3 0 8 - Y L
1 1 3 - O R
B A S I C E N G I N E B L O C K D I A G R A M
A P P L I C A T I O N
B L O C K D I A G R A M
E L E C T R O N I C S E R V I C E
T O O L C O N N E C T O R
M O N
I T O R I N G S Y S T E M
D I S C O N N E C T
S W I T C H
1 5 A M P
B R E A K E R
C O O L A N T
T E M P E R A T U
R E
S E N S O R
J 4 / P 4 T H R O U G H
J 1 9 / P 1 9
R E L A Y
J 2 1 / P 2 1
J 4 7 / P 4 7
P 3 1 / J 3 1
0 5
1 0
1 5
2 0
2 5
3 0
X 1 0 0
2 4 V
M P H
k m
/ h
4 4
A U T
P
R
C A T D a t a
L i m k
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CHAPTER : 3500B
ANALOG SENSOR POWER SUPPLY
ELECT. ENG. CONTROL
7Page:
P22 J22
ENGINE COOLANTTEMPERATURE SENSOR
FILTERED OILPRESSURE SENSOR
+V ANALOGANALOG RETURNSIGNAL
+V ANALOGANALOG RETURNSIGNAL
P23 J23
TURBO OUTLETPRESSURE SENSOR
+V ANALOGANALOG RETURNSIGNAL
P25 J25
RIGHT TURBO INLET PRESSURE SENSOR
+V ANALOGANALOG RETURNSIGNAL
P27 J27
ATMOSPHERICPRESSURE SENSOR
+V ANALOGANALOG RETURNSIGNAL
P28 J28
LEFT TURBO INLETPRESSURE SENSOR
+V ANALOGANALOG RETURNSIGNAL
3630
P1 J1
P43 J43
+V ANALOGANALOG RETURNSIGNAL
CRANKCASEPRESSURE SENSOR
P48 J48
+V ANALOGANALOG RETURNSIGNAL
UNFILTERED OILPRESSURE SENSOR
ABC
ABC
ABC
ABC
ABC
ABC
ABC
ABC
J21 P21
5 ± 0.5 VOLTS
+V ANALOG SUPPLYANALOG RETURN
ECM
The Analog Sensor Power Supply provides power to all the analog sensors (pressure and temperature).
The ECM supplies 5.0 ± 0.5 Volts DC (Analog Supply) through the J1/P1 connector to each sensor.
A power supply failure will cause all analog sensors to appear to fail.
The power supply is protected against short circuits, which means that a short in a sensor or a wiring
harness will not cause damage to the ECM.
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CHAPTER : 3500B
DIGITAL SENSOR POWER SUPPLY
ELECT. ENG. CONTROL
8Page:
+ V DIGITAL SUPPLY- V DIGITAL RETURN
2935
P1 J1
ABC
J31 P31
+V DIGITALDIGITAL RETURN
SIGNAL
RIGHT EXHAUST TEMPERATURE SENSOR
ABC
J35 P35
THROTTLEPOSITION SENSOR
+V DIGITALDIGITAL RETURN
SIGNAL
8 ± 0.5 VOLTS
ABC
J30 P30
+V DIGITALDIGITAL RETURN
SIGNAL
LEFT EXHAUST TEMPERATURE SENSOR
AB
C
J84 P84
+V DIGITALDIGITAL RETURN
SIGNAL
FAN SPEED SENSOR
ECM
The ECM supplies power at 8 ± 0.5 Volts through the J1/P1 connector to the following circuits:
- Throttle Position Sensor
- Fan Speed Sensor (if installed)
- Exhaust Temperature Sensors
The power supply is protected against short circuits, which means that a short in a sensor will not cause
damage to the ECM
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
9Page:
SYSTEM POWER SUPPLIES
The 3500B EUI system has one external and five internal power supplies with various voltages as shown.
EXTERNAL POWER SUPPLIES
ECM power supply 24 Volts
INTERNAL POWER SUPPLIES
Speed/Timing Sensor power supply 12.5 Volts
Injector power supply 105 Volts
Analog Sensor power supply 5 Volts
Digital Sensor power supply 8 Volts
Wastegate Control Solenoid power supply 0 - 24 Volts
ECM Power Supply
The power supply to the ECM and the system is drawn from the 24-Volt machine battery. The principle
components in this circuit are:
- 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.)
NOTE: The Ground Bolt and the Machine Interface Connector are the only power supply
components mounted on the engine.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
10Page:
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.
On the 3512B and 3516B, two of the internal power supplies are used for the injectors. If a failure
occurs, only one bank of injectors could have failed. On the 3508B, only one of the internal power
supplies is used. As previously mentioned, the same ECM is used on all three configurations.
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 orreconnect the injector as appropriate.
Speed/Timing Sensor
One Speed/Timing Sensor is installed and it serves four basic functions in the system:
- Engine speed detection
- Engine timing detection
- Cylinder and TDC identification
- Reverse rotation protection
The ECM supplies 12.5 ± 1 Volts to the Speed/Timing Sensor.
Connector pins A and B transmit the common power supply to the sensor. The C connector pin transmits
the signals from the sensor to the ECM.
This power supply is not battery voltage, but is generated and regulated within 1.0 Volt by the ECM.
This power supply and the Speed/Timing Sensor are vital parts of the EUI system. A failure of the sensor
will result in an engine shutdown.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
11Page:
The Speed/Timing Sensor is mounted on the rear housing and is
self-adjusting during installation.
This type of sensor does not have a typical fixed air gap. However, the sensor is not in direct contact with
the timing wheel, but does run with zero clearance. A 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 sensor failure will be indicated by the active fault screen on the service tool. An intermittent failurewill be shown in the logged fault screen.
The sensor has a dedicated power supply. A power supply failure at the ECM will cause the sensor to
fail.
The sensor head is extended prior to installation. The action of screwing in the sensor pushes the head
back into the body after the head contacts the timing wheel.
During installation, it is essential to check that the sensor head is not aligned with a wide slot in the
timing wheel. If this condition occurs, the head will be severed when the engine is started, and somedisassembly may be necessary to remove the debris.
Timing calibration is normally performed after the following procedures:
1. ECM replacement
2. Speed/timing sensor replacement
3. Engine timing adjustment
4. Camshaft, crankshaft or gear train replacement
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
12Page:
The engine Coolant Temperature Sensor is located at the front of the engine on 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 Vital Information Management System (VIMS) or Caterpillar Monitoring System Coolant
Temperature Gauge over the CAT Data Link.
The High Coolant Temperature Warning Alert Indicator and Gauge on the VIMS or 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 for coolant temperature indication.
The Cold Mode engine control (i.e. elevated low idle and timing reference for cold mode operation).
The Ether Aid control as a reference for Ether Aid operation.
The sensor supplies the temperature signal for the following functions:
- Caterpillar Monitoring System or VIMS instrument display, warning lamps and alarm
- Demand Control Fan (if so 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 so
equipped)
- Reference temperature for Cold Mode operation
NOTE: All analog sensors use the common analog power supply of 5.0 ± 0.2 Volts.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
13Page:
The Aftercooler Temperature Sensor is mounted at the rear of the block (Off-highway Truck) and
measures coolant temperature in the aftercooler circuit.
The ECM uses the sensor signal as a reference for the fan control. When high aftercooler temperatures
are reached, the cooling fan speed is increased. Very high aftercooler temperatures will cause a VIMS
warning event to be logged.
NOTE: This sensor measures the ability of the aftercooler to cool the air sufficiently for
combustion. As a general rule, for every 1 degree that the combustion air is reduced in
temperature, the exhaust will be reduced by approximately 3 degrees. High inlet manifold
temperatures can significantly shorten the life of exhaust system components (i.e. exhaustmanifolds, valves, turbochargers and pistons).
Three pressure sensors are used for the measurement of oil pressure:
- Two Oil Pressure Sensors (filtered and unfiltered)
- Atmospheric Pressure Sensor
The filtered and unfiltered pressure sensors are used together to measure oil filter restriction.
The filtered oil pressure sensor is used to measure lubrication oil pressure for the operator on the dash
panel and for the technician on ET. The atmospheric pressure sensor is used with this oil pressure sensorto calculate the gauge pressure reading.
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CHAPTER : 3500B
OIL PRESSURE MAP
ELECT. ENG. CONTROL
14Page:
O I L P R E S S
U R E I N k P a
600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 180060
80
100
120
140
160
180
200
220
240
260
280
300
ENGINE RPM
1900
320
340
8.7
11.6
14.5
17.4
20.3
23.2
26.1
29
31.9
34.8
37.7
40.6
43.5
46.4
49.3
O I L P R E S S
U R E I N P S I
kPa x 0.145 = PSI
2000
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 running at low idle, the ECM reads adequate oil pressure. No faults are
indicated and no logged event is generated. A delay built into the system prevents false events from
being logged after start-up or after a filter change.
If the engine oil pressure decreases below the lower line, the following occurs:
- An event is generated and logged in the permanent ECM memory.
- A Category 3 Warning (alert indicator, action lamp and alarm) is generated on the VIMS and
Caterpillar Monitoring System.
- The engine is derated (if so equipped) to alert the operator.
The width of the pressure band between the two lines is sufficient to prevent multiple alarms and events
or a flickering warning lamp. (This pressure separation is referred to as hysteresis).
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
15Page:
The Atmospheric Pressure Sensor is installed on the ECM mounting adapter and is vented to the
atmosphere. This sensor has various functions which are fully described later in the presentation.
Briefly, it performs the following functions:
Ambient pressure measurement for automatic altitude compensation and automatic air filter
compensation.
Absolute pressure measurement for the fuel ratio control, ET, filter restriction, and Caterpillar
Monitoring System panel (gauge) pressure calculations.
All pressure measurements require the atmospheric pressure sensor to calculate gauge pressure. All
pressure sensors in the system measure absolute pressure. The sensors are used individually in the case
of atmospheric pressure (absolute pressure measurement). They are used in pairs to calculate gauge
pressures (oil and boost) and filter restriction.
All the pressure sensor outputs are matched to the Atmospheric Pressure Sensor output during
calibration. Calibration can be accomplished automatically using the ET service tool or by turning on the
key start switch without starting the engine for five seconds. The Atmospheric Pressure Sensor performs
four main functions:
1. Automatic Altitude Compensation (Maximum derate 24%)
2. Automatic Filter Compensation (Maximum derate 20%)
3. Part of the pressure calculation for gauge pressure readings
4. Reference sensor for pressure sensor calibration
A foam filter is installed below the sensor to prevent the entry of dirt.
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CHAPTER : 3500B
ENGINE POWER DERATING MAP
ELECT. ENG. CONTROL
16Page:
100%
98%
96%
94%
92%
90%
88%
86%
84%
82%
80%
78%
76%
74%
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
8,210
8,920
9,630
10,340
11,050
11,760
12,470
13,890
14,600
15,310
16,020
16,730
17,440
13,180
7,500
72%
ACCORDING TO ATMOSPHERIC PRESSURE
ATMOSPHERIC PRESSURE IN kPa
P E R C E N T O F F U L L L O A D P O W E R
A L T I T U D E I N F E E T
Atmospheric pressure measurement by the sensor provides an altitude reference for the purpose of
Automatic Altitude Compensation.
The graph shown here describes how derating on a typical 3500B starts at 7500 ft. and continues linearlyto a maximum of 17000 ft. Other engines may start between 4000 and 12000 ft. depending on theapplication.
The advantage of the EUI system is that the engine always operates at the correct derating setting at allaltitudes. The system continually adjusts to 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 EUIsystem.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
17Page:
The Turbocharger Inlet Pressure Sensor is mounted between the air filter and the turbocharger.
This sensor is used in conjunction with the atmospheric pressure sensor to measure air filter restriction for
engine protection purposes. The difference between the two pressure measurements is used as the filter
differential pressure. The engine ECM uses this calculation to determine whether derating is necessary to
protect the engine against the effects of excessive filter restriction.
This function is referred to as Automatic Air Filter Compensation.
Depending on the application and air intake system configuration, either one or two Turbocharger Inlet
Pressure Sensors may be used.
If the machine is equipped with an ether start system, the ECM will automatically inject ether from the
ether cylinders) during cranking. The operator can also inject ether manually with the ether switch in the
cab. Ether will only be injected if the engine coolant temperature is below 10°C (50°F) and engine speed
is below 1200 rpm.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
18Page:
Automatic Filter Compensation means that the engine is protected against the effects of plugged filters.Derating is automatic as follows:
- Air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water)
- Engine power derating starts at the rate of 2% per 1 kPa of ∆P
- Maximum derate 20%
- Event is logged when air filter restriction (∆P) exceeds 6.25 kPa (30 in. of water)
These ∆P specifications are typical examples. The actual values may vary depending on the application.
Derating is retained at the maximum ∆P until the key start switch is cycled off and on.
NOTE: If only one filter is plugged, the ET service tool and Caterpillar Monitoring System will
display the highest ∆P of the two. Derating is also based on the highest ∆P of the two.
The Turbocharger Outlet Pressure Sensor measures absolute pressure downstream of the aftercooler.
Boost (gauge) pressure can be read with the service tools. This measurement is a calculation using the
Atmospheric Pressure and the Turbocharger Outlet Pressure Sensors.
A failure of this sensor will cause the ECM to default to a zero boost condition. This failure can result in
a 60% loss in engine power.
The function of the sensor is to enable the Air/Fuel Ratio Control which reduces smoke, emissions and
maintains engine response during acceleration. The system utilizes manifold pressure and engine speed
to control the air/fuel ratio. Engine fuel delivery is limited according to a map of gauge turbo outlet
pressure and engine speed.
The Air/Fuel Ratio Control setting is adjustable on 3500B machine applications using the service tool.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
19Page:
The ECM uses gauge pressure measured from the Crankcase Pressure Sensor and the Atmospheric
Pressure Sensor to determine whether crankcase pressure is excessive (i.e. a piston allowing excessive
blowby which could soon cause considerable damage).
The ECM will warn the operator of possible damaging conditions and record adverse conditions in the
memory.
A possible cause of excessive crankcase pressure could be piston damage or a piston ring failure. An
early warning means that the engine can be shut down without catastrophic secondary damage.
Crankcase pressure is compared with atmospheric pressure. The result is crankcase (gauge) pressure (i.e.
pressure above ambient).
The trip points are:
WARNING 2 kPa (10 in. of water)
EVENT 3.5 kPa (17in. of water)
A Crankcase Pressure Sensor is mounted on the right side of the engine.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
20Page:
Two Exhaust Temperature Sensors are installed on the 793C. The sensors are mounted between the
exhaust manifold and the turbocharger.
The ECM uses the sensors to warn the operator of possibly damaging conditions and logs an event in the
memory.
An engine derate occurs on Off-highway Trucks if excessive exhaust temperatures are reached.
The Throttle Position Sensor provides engine speed control for the 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 Power Supply at the ECM.
The Throttle Position Sensor is shown on the machine wiring side of the diagram.
NOTE: This system eliminates all mechanical linkage between the operator's engine speed controls
and the governor (ECM).
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
21Page:
Demand Fan Controls
Two types of thermostatic fans are used in 3500B machine applications. Some Off-highway Trucks and
Track-type Tractors are equipped with a variable speed fan drive clutch. Some Wheel Loaders are
equipped with a hydraulic fan drive.
Both systems use the ECM and the temperature sensor as the engine coolant temperature reference, and
both are controlled by the ECM. If an electrical failure of the system occurs, the fan will go to maximum
(100%) speed.
The advantages of the systems are:
- Reduced fuel consumption in most conditions
- Reduced engine overcooling at low ambient temperatures
- Faster engine warm-up
- More engine power available at the flywheel
- Reduced noise
Engine Mounted Switches
Three EUI circuit switches are mounted on the engine:
The Low Oil Level Switch signals the ECM if the engine oil level decreases below a predetermined
level. The ECM then warns the operator of possible damaging conditions and logs an event.
The Filter Differential Pressure Switch signals the ECM if the pressure across engine fuel filter is
excessive and the filter needs to be changed.
The Coolant Flow Switch provides the operator with a warning if a failure in the coolant circuit causing
no flow occurs. The switch contacts are normally open with no flow.
The Coolant Flow Switch, like the Oil Level Switch, is a passive sensor (i.e. no power supply) which
means that the ECM cannot determine if the switch or associated circuit has failed. A system problem
could be determined if coolant flow is indicated with the engine stopped or if no coolant flow is indicated
with the engine running.
The functions of these switches may be checked using the status screen. The Coolant Flow Switch
should indicate if flow is present. This function should be checked both with the engine running and
stopped.
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
22Page:
The Throttle Back-up Switch provides a "limp home" mode in the event that the Throttle Position
Sensor becomes inoperative.
If the ECM detects either an invalid or no signal, the Throttle Back-up Switch is automatically activated.
When activated, the operator may operate the switch to raise the engine speed to 1200 rpm for as long as
the switch is operated. If the Throttle Position Sensor signal is received again, the switch is deactivated.
Engine Shutdown Systems
The Ground Level Shutdown Switch is connected to the ECM through the machine and engine wiring
harnesses.
The switch signals the ECM to cut electrical power to the injectors, but maintains power to the ECM.
This feature also enables the engine to be cranked without starting for maintenance purposes.
No other circuits may be connected to this system. The user defined shutdown feature may be used in
conjunction with other circuits.
The User Defined Shutdown feature (if installed) may be used to connect 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 also be shown on the ET status
screen.
For example, when installed on an Off-highway Truck, this feature is programmed to function only
during the following conditions:
Parking brake is ENGAGED
Transmission is in NEUTRAL
Machine ground speed is at zero
Not all machines will have this feature installed
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CHAPTER : 3500B
COMPONENT DIAGRAM
ELECT. ENG. CONTROL
23Page:
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. Actual flow is determined by
engine speed and temperature. Ether injection is disabled when the coolant temperature exceeds 10°C
(50°F) or engine speed exceeds 1200 rpm.
A manual mode allows ether injection when the above parameters permit. In the manual mode, a
continuous flow of ether is injected. The ether injection status can be read on the ET status screen.
Prelubrication System
The ECM controls the prelubrication system. This system uses the coolant temperature, engine speed and
oil pressure as its references to determine the need for prelubrication.
The system is activated when the key start switch is turned to the start position. The system prevents
starter motor engagement until the oil pressure increases.
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CHAPTER : 3500B
LOGGED EVENTS
ELECT. ENG. CONTROL
24Page:
Logged events listed on the appropriate ET screen are conditions which are abnormal to the operation of
the engine. For example:
- High coolant temperature
- Low oil pressure
- Filter restriction
- Excessive engine speed
These events are not normally electronic problems, but might be conditions caused by a plugged radiator,
low oil level, maintenance or operator deficiencies.
A list of possible events for the 3500B engine is included on the next page.
Some of the parameters listed in this presentation are used in the ET events list. They are as follows:
- High coolant temperature
- High exhaust temperature
- High aftercooler temperature
- Crankcase pressure
- Loss of coolant flow
- Low (lubrication) oil pressure (according to the oil pressure map)
- User defined shutdown
- Air filter restriction
- Fuel filter restriction
- Oil filter restriction
- Engine oil level
- Engine overspeed histogram
- High boost
- Low boost
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2 5
P a g e:
IMPLEMENTCONTROL MODULE
VIMS
3F
SERVICE TOOLCONNECTORS CAT DATA
ENGINE ELECTRONICCONTROL MODULE
(ECM)
CAT
ELECTRONIC TECCOMMUNICATION
ADAPTER
LAPTOPCOMPUTE
POWERTRAINCONTROL MODULE
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2 6
P a g e:
TRANSMISSIONCONTROL ECM
ADEM I
CONTRO
SERVICELAMP
MESSAGE CENTERMODULE
GAUGE CLUSTERMODULE
KEMO
SENSORS
VIMS/VIDSINTERFACE
MODULE
VIMS ONLYINTERFACE
MODULE
SENSORS
VIMSSERVICE TOOL
ANDSOFTWARE
CAT DATA LINK
SERVICEKEYSWITCH
ACTIONLAMP
ACTIONALARM
VIMS MAIN MODULE
DISPLAY DATA LINK
VIMS
RS-232PORT
CAT DATA LINK
VITAL INFORMATION
MANAGEMENT SYSTEM(VIMS)
SPEEDOMETER/TACHOMETER
MODULE
3F
KEYPADDATA LINK
IMPLEMENTCONTROL ECM
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CHAPTER : 3500B
TIMING CALIBRATION
ELECT. ENG. CONTROL
27Page:
REFERENCE EDGE TO TDC DISTANCE
REFERENCEEDGE ASSUMED
CYL. NO. 1 TDCACTUAL
CYL. NO. 1 TDC
TIMINGREFERENCE
OFFSET
MAXIMUM TIMING REFERENCE OFFSET ± 7 DEGREES
TIMING CALIBRATIONSENSOR SIGNAL
TIMINGWHEEL
± 7 °
-7° +7°
As the Speed/Timing Sensor uses the timing wheel for a timing reference, timing calibration improves
fuel injection accuracy by correcting for any slight tolerances between the crankshaft, timing gears and
timing wheel.
During calibration, the offset is saved in the ECM EEPROM (Electrically Erasable Programmable Read
Only Memory). The calibration offset range is limited to ± 7 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.
The timing must be calibrated after performing the following procedures:
1. ECM replacement
2. Speed/timing sensor replacement
3. Timing wheel replacement
4. Camshaft, crankshaft or gear train replacement
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CHAPTER : 3500B
E -TRIM CODE READING
ELECT. ENG. CONTROL
28Page:
PART No.
TRADE MARK
SERIAL No.
TRIM CODE SERIAL No. BAR CODE
The code identifies the discharge and timing characteristics of the injector and is programmed into the
ECM.
If the injector is replaced, the new code must be entered via ET’s calibration menu.
Old injectors are not coded, the default code 1100 must be entered.
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CHAPTER : 3500B
E-TRIM FEATURE
ELECT. ENG. CONTROL
29Page:
ALL ENGINES BUILD STARTING MAY 15, 1996 HAVE THE E-TRIM FEATURE ON THEIRPERSONALITY MODULE AND INJECTORS CODED WITH AN E-TRIM CODE
THE SOFTWARE COMPENSATES FOR INJECTOR VARIATION IN TIMING AND DISCHARGE.
THE E-TRIM IS A 4 DIDGIT CODE ETCHED ON THE INJECTOR TAPPET
IF IT IS NOT POSSIBLE TO REPROGRAM AN INJECTOR CODE IMMEDIATELY THE ENGINE
WILL NOT BE SEVERELY HARMED , ALTHOUGH IT SHOULD BE REPROGRAMMED AS SOONAS POSSIBLE TO OPTIMIZE ENGINE PERFORMANCE AND PREVENT ANY LONG TERMDETRIMENTAL EFFECTS
CAT Electronic technician - CalibrationsCAT Electronic technician - Calibrations
Select Calibration
ENGINE 3508B
Pressure Sensor Calibration
Timing CalibrationInjector Code calibration
Injector 1 1100Injector 2 1100Injector 3 1100Injector 4 1100Injector 5 1100Injector 6 1100Injector 7 1100Injector 8 1100
Injector Code
Change
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CHAPTER : 3500B
COLD MODE TIMING
ELECT. ENG. CONTROL
30Page:
30° C 50° C 60° C
COOLANT TEMPERATURE IN DEGREES FAHRENHEIT
LOW ENGINE SPEEDFIXED TIMING
HIGH ENGINE SPEED
TOWARMMODE
TIMINGADVANCE
BTDC
Cold Mode
The desired timing is retarded during Cold Mode operation based on coolant temperature and engine
speed.
1. For coolant temperatures at or below 86°F:
Timing will be retarded to protect the engine against high cylinder pressures. Idle is elevated to 1300
rpm (with parking brake ON and transmission in NEUTRAL).
2. For coolant temperatures above 86°F and below 140°F, the timing will advance. For engine speeds
below 1200 rpm, timing will vary according to the low engine speed line.
NOTE: Neither fuel nor engine speed is limited during Cold Mode operation. When cold mode
operation is deactivated, the desired timing returns to normal operation.
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CHAPTER : 3500B
FRC OFFSET
ELECT. ENG. CONTROL
31Page:
VALID NUMBERS -25 to +25
-25 +25
LESS SMOKESLOWER RESPONSE
MORE SMOKE
FASTER RESPONSE
0AcceptableresponseClean exhaust
©1994 DenebaSystems,Inc. ©1994 DenebaSystems,Inc.
The Fuel Ratio Control has been optimized to provide excellent performance and black smoke control
without any need for adjustment. There should be no need to use the “Fuel Ratio Control Offset” except
for special circumstances.
Changing the Fuel Ratio Control Offset parameter allows the customer tailoring of the fuel to air ratio in
order to compensate for winter blend fuel, individual costumer preference etc.
Use of the Fuel Ratio Control Offset parameter will NOT affect overall power output of the engine. The
parameter should NOT be used to mask possible engine performance which may exist.
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CHAPTER : 3500B
COLD START LOGIC
ELECT. ENG. CONTROL
The ECM cuts out each cylinder for a brief amount of time to see if that injec-tor is contributing to power. If not injec-
tion will be stopped to that cylinder.TheECM will retest any cutout cylinder(injector) every so often to see if it start-ed to fire or not.
HELPS REDUCE WHITE SMOKE DURING
ENGINE WARM UP
In cold mode the ECM stops injection
to non-firing injectors until the enginehas reached a certain temperature (coolanttemperature).
Recommended