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G643(E) Service Manual
Chapter 5. Engine Management System (EMS)
166
Ignition Management
In the normal course of events, with the engine
operating at the correct temperature in defined
conditions, the SECM will use load and engine
speed to derive the correct ignition timing. In
addition to load and speed there are other
circumstances under which the SECM may need to
vary the ignition timing, including low engine coolant
temperature, air temperature, start-up, and idle
speed control.
SECM Electrical Mounting
Recommendations
In order to prevent the possibility of any SECM
malfunctions due to EMI/RFI emissions, the SECM
mounting and harness recommendations listed
below:
• The SECM should be mounted in a location that
minimizes the amount of EMI the module is
exposed to by locating it as far as practical from
all high tension components, such as ignition coils,
distributors, spark plug wires, etc. It is
recommended that the SECM be mounted at least
29.5” (749 mm) away from the distributor and
ignition coil, and at least 20” (508 mm) from the
nearest plug wire.
• All wiring harnesses should be routed to minimize
coupling (both radiated and conducted), and be
securely fastened to minimize movement and
maintain proper clearance between the SECM
and all ignition system components.
• The OEM must ensure that a high-quality ground
connection between the SECM and battery
negative (–) is provided and can be maintained for
the useful life of the vehicle. This may require the
use of star-type washers on all ground lug
connections between the SECM and the battery
and/or special preparation of all mating surfaces
that complete the ground connection in order to
ensure that the connection is sound.
SECM Wiring Diagrams for G643E
CAUTION—PROPER WIRING
To prevent system faults be sure to follow good
wiring practices. Poor wiring may cause unexpe-
cted or intermittent failures not related to MI-07
components.
Содержание G643
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Страница 43: ...G643 E Service Manual Chapter 3 Engine Mechanical System 41 Engine Exploded View...
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Страница 132: ...G643 E Service Manual Chapter 4 Engine Electrical System 130 2 Alternator and outer terminal connection inspection...
Страница 181: ...G643 E Service Manual Chapter 5 Engine Management System EMS 179 SECM Wiring Diagrams for G643 LP Engine...
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