G424F(FE) Service Manual
Chapter 5. Engine Management System (EMS)
142
There are multiple limp-home modes available with
electronic throttle control:
1.
If the throttle itself is suspected of being
inoperable, the SECM will remove the power to
the throttle motor. When the power is removed,
the throttle blade returns to its “default” position,
approximately 7% open.
2.
If the SECM can still control the throttle but some
other part of the system is suspected of failure,
the SECM will enter a “Reduced Power” mode. In
this mode, the power output of the engine is
limited by reducing the maximum throttle position
allowed.
3
. In some cases, the SECM will shut the engine
down. This is accomplished by stopping ignition,
turning off the fuel, and disabling the throttle.
Picture courtesy of Robert Bosch GmbH
Figure 15. Throttle Body Assembly Exploded View
Ignition System
Spark-ignited engines require accurate control of
spark timing and spark energy for efficient
combustion. The MI-07 ignition system provides this
control. The system consists of the following
components:
• SECM
• Ignition coil drivers *
• Ignition coil(s) *
• Crankshaft position sensor *
• Crankshaft timing wheel *
• Cam position sensor *
(sequential ignition or fuel injection only)
• Cam timing wheel *
(sequential ignition or fuel injection only)
• Spark plugs *
The SECM, through use of embedded control
algorithms and calibration variables, determines the
proper time to start energizing the coil and fire the
spark plug. This requires accurate crank/camshaft
position information, an engine speed calculation,
coil energy information, and target spark timing. The
SECM provides a TTL compatible signal for spark
control. The coil must contain the driver circuitry
necessary to energize the primary spark coil
otherwise an intermediary coil driver device must be
provided. The SECM controls spark energy (dwell
time) and spark discharge timing.
Wasted Spark DIS Ignition System
The G424F and G424FE engine has a wasted spark
ignition system (2 cylinders per coil).
Wasted spark ignition is a type of distributor-less
ignition system where a pair of multi tower coils is
mounted near the spark plugs. The DIS system
eliminates the wear associated with most distributor
type ignition systems. The wasted spark ignition
fires pairs of cylinders at each ignition event. One
cylinder fires on the compression stroke as is normal.
However, the complementary pair in the firing order
is fired simultaneously while that particular cylinder
is on the exhaust stroke. Since the ionized exhaust
gases require little spark energy, the majority of the
ignition energy from the coil goes to the spark plug
in the cylinder on the compression stroke.
The DIS coil pack can be mounted close to the
spark plugs, thereby improving ignition lead routing
Summary of Contents for D20G
Page 2: ......
Page 5: ...Specifications TORQUE SPECIFICATIONS SB2004E00 D e c 1 9 9 8 ...
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Page 138: ...Diesel Engine Engine System 124 NOTE The crankshaft must rotate freely by hand 02900058 ...
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Page 341: ...4TNV98 4TNE98 Diesel Engine Section 3 Engine 87 4TNE98 Engine Figure 6 1 ...
Page 423: ...4TNV98 4TNE98 Diesel Engine Section 4 Fuel System 169 Fuel System Components Figure 7 1 ...
Page 477: ...4TNV98 4TNE98 Diesel Engine Section 7 Starter Motor 223 Starter Motor Troubleshooting ...
Page 494: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 240 Troubleshooting Charts ...
Page 495: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 241 ...
Page 496: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 242 ...
Page 498: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 244 4TNE98 Engine ...
Page 499: ...Service Manual G424FE LP Engine G424F LP Gasoline Engine G20G G25G G30G SB4320E00 Jan 2008 ...
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Page 529: ...G424F FE Service Manual Chapter 2 Recommended Maintenance 29 ...
Page 534: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 34 MAIN BEARINGS 0 50 UNDERSIZE ...
Page 584: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 84 ...
Page 729: ...G424F FE Service Manual 229 Chapter 8 Basic Troubleshooting ...
Page 731: ...G424F FE Service Manual 231 Chapter 8 Basic Troubleshooting ...
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Page 820: ...Power Train System Operation 14 Hydraulic System ...
Page 822: ...Power Train System Operation 16 Hydraulic System ...
Page 824: ...Power Train System Operation 18 Hydraulic System ...
Page 826: ...Power Train System Operation 20 Hydraulic System ...
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Page 1023: ...A374081 01 ELECTRIC SCHEMATIC MODEL D20 25 30G EM0K2 EM0K3 Cummins B3 3 ...
Page 1024: ...A654030 00 ELECTRIC SCHEMATIC MODEL D20 25 30G EM0QM EM0QN Yanmar 4TNE98 Tier 3 ...
Page 1025: ...A604500 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QF EM0QG GM G424F Non Certi LP ...
Page 1026: ...A604510 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QH EM0QJ GM G424F Non Certi GAS ...
Page 1027: ...A604516 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QY EM0QZ GM G424FE Tier 3 LP ...
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Page 1059: ...Safety Section 29 Lean away from the direction of fall Lean forward ...
Page 1071: ...General Section 41 Typical Example Side Shifter Serial Number If Equipped ...