Datsun 1980 200SX Service Manual page 91

EFI
System
Openltion
ENGINE FUEL
EFI
SYSTEM
operating conditions
into electronic
signals
These
signals
are
sent to the
control unit where the optimum in
jector open
valve time period is
com
puted according
to
the infonnation
stored in the
memorY
for control of
fuel injection quantity
The Electronic Fuel Injection EFI
system
is
used
to
control fuel
supply
electrically
in
place
of
the
conven
tional carburetor system
The EFl system
employs
various
types
of
sensors
to convert the
engine
Various
sensors
I
For
detecting engine operation
1
Electrical signal
Control
unit
I
For calculating optimum
fuel
injecti
on
Electrical
signal
Injector
I
For
injecting
fuel
EFISYSTEM OPERATION
FUEL FLOW SYSTEM
Fuel
is
sucked from the fuel tank
into the fuel pump from which it is
discharged
under pressure
As it flows
through
the
mechanical fuel
damper
pulsation
in
the fuel flow
is damped
Then the fuel
is
filtered
in the
fuel
filter goes through
the fuel line and is
injected
into
the intake manifold cyl
inder
branch
from
the
injector
Surplus
fuel
is
led through the pres
sure
regulator
and
is
returned
to
the
fuel tank The pressure
regulator
con
trois the injection
pressure
in such
a
manner
that
the pressure difference
between the fuel pressure and the in
take manifold
vacuum
is
always 250
kPa 2 5 5
kg
cm
36 3
psi
J
D
EF 4
FEATURES
The EFl system utilizes electronic
elements such
as
integrated
circuits
ICs resistors thennistors etc
for
electrically controlling the
amount
of
fuel
injected corresponding
to
changes
in
engine operations
Because of this
use
of electronic
components
this
system
is
able
to
provide
a
quick
response
to
changes
in
operating
con
ditions
and
serves
to
improve
the
engine
perfonnance and
to
reduce
fuel consumption and hannful gases
J
r
n
L
SEFQ83