Section 07
ENGINE MANAGEMENT (4-TEC)
Subsection 02
(OVERVIEW)
SMR2002-077_07-02A.FM
07-02-9
This engine management system controls both
the fuel injection and the ignition timing.
As shown in the 1503 4-TEC CONTROL SYSTEM
illustration, the EMS ECU is the central point of the
fuel injection system. It reads the inputs, makes
computations, uses pre-determined parameters
and sends the proper signals to the outputs for
proper engine management.
The EMS ECU also stores the fault codes and gen-
eral information such as: operating conditions, ve-
hicle hours, serial numbers, customer and mainte-
nance information.
Electronic Fuel Injection
The EMS ECU reads the signals from different sen-
sors which indicate engine operating conditions at
milli-second intervals.
Signals from sensors are used by the EMS ECU to
determine the injection parameters (fuel maps) re-
quired for optimum air-fuel ratio.
The CPS, the MATS, the MAPS and the TPS are
the primary sensors used to control the injection
and ignition timing. Other sensors (like tempera-
ture sensors, etc.) are used for secondary input.
NOTE:
The EGT, OPS and OSPS sensors does not
provide control inputs to the EMS ECU. Their sole
purpose is to protect the engine components by
emitting a warning signal and/or a fault code in the
event of overheating or low oil pressure or TOPS
valve fault.
Ignition System
The ignition system is a digital inductive type. The
EMS ECU control the ignition system parameters,
such as spark timing, duration and firing in order
to achieve the proper engine requirements.
Ignition Coils
Three separate ignition coils induce voltage to a
high level in the secondary windings to produce a
spark at the spark plug.
The ignition coils receive input from the EMS ECU.
Each coil provides high voltage to its correspond-
ing spark plug.
This ignition system allows spark plugs to spark
independently.
NOTE:
Ignition coil cables are not interchangeable
due to different lengths.
All three ignition coils are located on the cylinder
head directly on the spark plugs.
1. Ignition coils
Ignition Timing
The EMS ECU is programmed with data (it con-
tains ignition mappings) for optimum ignition tim-
ing under all operating conditions. Using engine
operating conditions provided by the sensors, the
EMS ECU controls the ignition timing for optimum
engine operation.There is no mechanical adjust-
ment to perform.
Knock Sensor
A knock sensor is mounted on the engine block
behind the air intake manifold. It detects specific
vibration that would be typically generated by en-
gine detonation. If detonation occurs, the knock
sensor detects it and the EMS ECU retards the
ignition advance temporarily (it goes in a specific
mode) until detonation stops. The EMS ECU is
able to evaluate the knocking cylinder and modi-
fies the ignition advance just on the detonating
one.
Engine Modes of Operation
The EMS ECU controls different operation modes
of the engine to allow proper operation for all pos-
sible conditions: Cranking, start-up, idle, warm up,
part load, full load, Sea-Doo LK™ (learning key, lim-
ited vehicle speed), engine speed limiter, drowned
engine and limp home (see below).
1
R1503motr213A
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Содержание GTX 4-TEC 5573 2002
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