CLEAR FLOOD MODE
POWER REDUCTION MODE
AND OLDER MODELS)
(1996
If the engine floods, it can be cleared by opening the
throttle half way (50%). (Open throttle handle until re-
sistance from secondary throttle [Multi-Port only] is
felt.) The ECM discontinues fuel injector pulsation as
long as the throttle is between 50 to 75 % and the en-
gine RPM is below 300. If the throttle position be-
comes more than 75% or less than 50%, the ECM re-
turns to the starting mode.
The ECM will go into power reduction mode when the
following conditions are met:
1.
Low oil pressure
2. Engine overheat
3.
4.
Low I/O fluid level (MCM)
High transmission temperature (MIE)
RUN MODE
The ECM recognizes change of state in a discrete
switch input that identifies an abnormal condition that
may affect proper drive train operation.
When the engine is started and RPM is above 300,
the system operates in the run mode. The ECM will
calculate the desired air/fuel ratio based on these
ECM inputs: RPM, Manifold Absolute Pressure
(MAP) sensor, Intake Air Temperature (IAT) sensor
and Engine Coolant Temperature (ECT) sensor .
Higher engine load (from MAP) and colder engine
temperature (from ECT) requires more fuel, or a rich-
er air/fuel ratio.
As an engine protection feature, power reduction
mode allows normal fuel injection up to 2800 RPM.
Above 2800 RPM, fuel delivery is limited to half of the
injectors until RPM lowers to 1200 RPM when normal
fuel injection resumes.
This feature maintains maneuverability of the vessel
while removing the possibility of high RPM operation
until the problem is corrected.
ACCELERATION MODE
The ECM looks at rapid changes in Throttle Position
(TP)andprovidesextrafuelbyincreasingtheinjector
pulse width.
DECELERATION MODE
The IAC is similar to a carburetor dashpot. It provides
additional air when the throttle is rapidly moved to the
idle position to prevent the engine from dying.
FUEL CUTOFF MODE
No fuel is delivered by the injectors when the ignition
is OFF, to prevent dieseling. Also, fuel pulses are not
deliverediftheECMreceivesnodistributorreference
pulses, which means the engine is not running. The
fuel cutoff mode is also enabled at high engine RPM,
as an overspeed protection for the engine. When cut-
off is in effect due to high RPM, injection pulses will
resume after engine RPM drops slightly.
Index
90-823224--2 796
ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY) - 5C-21
| Categories | Mercury MerCruiser Manuals |
|---|---|
| Tags | Mercury MerCruiser 454 CID, Mercury MerCruiser 502 CID |
| Model Year | 1993, 1994, 1995, 1996, 1997 |
| Download File |
|
| Document File Type | |
| Copyright | Attribution Non-commercial |
(4 votes, average: 4.5 out of 5)
Marine readers have rated 1993 1997 Mercury-MerCruiser GM V8 454 CID 7.4L and 502 CID 8.2L Marine Engines Service Manual Number 16 4.5 out of 5.0 based on 4 product reviews. Hugely helpful service manual! Perfect. Thank you!
Manuals are all Important for Technician
This book is invaluable if you do your own repairs. Great book.
Could not find a copy until a search brought me here.
Excellent print.
Thank you