Datsun 1980 200SX Service Manual page 129

Trouble
Diagnoses
and
Corrections
ENGINE FUEL
Condition
Probable
cause
Problem
in the folloWing circuits
e
Throttle valve switch idle
contact
and
fulllhrottle
contact
Vacuum switch
e
Aidlow
meter
potentiometer
Air
temperature
sensor
e
Water
temperature
sensor
Altitude
sensor
e
Ignition
coil trigger input
circuit
e
Control
unit power
input circuit
e Injector
circuit
Afterfire
or
a
g
Problem in the
following circuits
Throttle valve switch idle
contact and
fulllhrottle
contact
Vacuum switch
e
Air
flow
meter
potentiometer
Air
temperature
sensor
Water
temperature
sensor
Injection
circuit
e
START
signal input
Check and corrective action
Check each
circuit
Then proceed
to
the
Component checks
Check each
circuit
Then
proceed
to
Component
checks
COMPONENT
CHECKS
To be
performed only
after circuit
tests
are
completed
Control
Air
flow
meter Fuel system
Problem
Injector Air
unit
Flap
Relay
Resist
sound regulator
replace
Fuel
pres
Injector
opera ance
leakage
ment
sure
test
tion
means
Engine
will
not start
X
X
I
X
X
X
X X X
Idle
too
high
or
too
rougli
X X
I
X
X
Engine
misfires
X
I
X
X X
X
Lack of
power
engine
X
X
X X X
will
not
rev
Hesitation
stumble
X X X
X
Poor
gas
mileage
or
X X X X
X
CO
too high
Engine
surgAs
I I
X X X X
X
Backfiring
I I
X X X
X
Afterbuming
I
I
X X
X X
X
EF 42