Datsun 1980 200SX Service Manual page 126

Condition
Engine idles
too
fast
cannot be
adjust
ed with idle speed
adjusting
screw or en
gine
idle is unstable
Engine
misfIres
ENGINE
EUEL
Trouble
Dia9nosessnd
Corrections
Probable
cause
Improper
wate temperature
sensor
circuit
iI
Malfunctioning air regulator
Improper intaJ
e an
exhaust
valve clearance
Malfunctioning
throttle valve
Malfunctioning
air
regulator
rJ
r
l
Improper ignition
circuit
Improper
EFI harness connectors
Improper
fuel line
Check and corrective action
Then proceed
to the
following checks
Fuel
pump
Alternator
L
tenninal
Oil
pressure
switch
Fuel
pump
relays
I
and 2
Check
circuit
Check
air regulator
and replace
if
necessary
Note If these
tests
are
satisfactory prOceed
to
Engine will
not start
Adjust
valve clearance
Check that
plate
is
closing
when throttle
is
released
and replace if
necessary
To
check
air
regulator proceed
to
the
following
steps
Start
engine
Pinch offhose
to air
regulator
Results
al Ifidle speed drops
perfonn
circuit test
If
no
fault
is
found
replace air regulator
b If idle
speed
remains
high
or
unstable
perfonn
the
following
checks
Check for manifold
vacuum
leaks includ
ing
at P
CV valve
V
C valve
dipstick
nd oil f1ller
cap
seals
If
no
problem is
found
perfonn
the fol
lowing
circuit tests
Throttle valve switch idle contact
and
full throttle
contact
Va 9u
urp
switch
Air
temperature
sensor
Water
temperature sensor
Control
Jtit
ground
circuit
Air flow
meter
potentiometer
Air regwator and fuel
pump
circuit
Ignition coil trigger input
circuit
Control unit
power
input
circuit
1
Inj
ctor
circuit
Then proceed
to
Component checks
Check ignition circuit
Pull EFI harness
connectors
apart
and check
for looseness and corrosion
including
groimd
circuits
Do
not forget
ignition
in
put
lead
Check fuel line for
blockage
Tank strainer
Fuel filter
Injectors
Fuel
pipes
EF 39