FUEL INJECTORS
PRESSURE REGULATOR ASSEMBLY
The EFI injector assembly is a solenoid-operated de-
vice, controlled by the ECM, that meters pressurized
fuel to a single engine cylinder. The ECM grounds the
injector solenoid, which opens a pintle valve, allow-
ing fuel to flow past the pintle valve. The injector tip
has holes that control the fuel flow, generating a coni-
cal spray pattern of finely atomized fuel at the injector
tip. Fuel is directed at the intake valve, causing it to
become further atomized and vaporized before en-
tering the combustion chamber.
The pressure regulator is a diaphragm-operated re-
lief valve with fuel pump pressure on one side, and
regulator spring pressure and intake manifold vacu-
um on the other. The regulator’s function is to main-
tain a constant pressure differential across the injec-
tors
at
all
times.
The
pressure
regulator
compensates for engine load by increasing fuel pres-
sure as engine vacuum drops.
An injector that is stuck partly open will cause loss of
pressure after engine shutdown. This can result in
long cranking times. Dieseling can also occur, be-
cause some fuel might be delivered to the engine af-
ter the ignition is turned OFF.
71716
s
r
q
Throttle Body Assembly
p
The throttle body assembly is attached to the ple-
num, and is used to control air flow into the engine,
thereby controlling engine output. The throttle valves
within the throttle body are opened by the operator
through the accelerator controls. During engine idle,
the throttle valves are almost closed, and air flow
control is handled by the Idle Air Control (IAC) valve,
described below.
o
n
l
m
k
J
i
The throttle body also provides the location for
mounting the Throttle Position (TP) sensor for sens-
ing throttle valve position.
g
h
f
d
c
e
a
b
a
72970
a - Needle Valve
b - Nozzle
c - Cap
d - O-Ring
e - Valve Stopper
f - Core
b
g - O-Ring
h - Spring
c
72800
i - Housing
j - Solenoid Coil
k - Tape
l - Bobbin
m- O-Ring
n - Inner Collar
o - Sleeve
p - Terminal
q - Connector
r - Filter
a - Throttle Body
b - Idle Air Control (IAC) Valve
c - Throttle Position Sensor
s - O-Ring
Index
90-823224--2 796
ELECTRONIC FUEL INJECTION (MULTI-PORT AND THROTTLE BODY) - 5C-27
| 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