Mitsubishi Eclipse Workshop Manual page 135

FUEL
-
On-vehicle Inspection
of
MPI
Components
13-69
-
>\
\r--r'>
-<-t >-
)y#
--
-
o
o
CRANK ANGLE SENSOR
(Vehicles built
up
to June 1992>
@
Equipment side
connector
Output characteristic
o
o
Engine control unit connector
njHtrl f-r_lsufl rl-__rHl_j_l
Hffiffiffi
ilft
o
o
7?UO873
OPERATION
o
The crank angle sensor senses the crank angle (piston position) of each cylinder, converts it into a pulse
signal and inputs it to the engine control unit. which then computes the engine speed and controls the
fuel
injection timing and ignition timing based on the input
signal.
o
Power
to the
crank angle sensor is supplied
from the control relay and is grounded
to the
body. The
crank angle sensor generates a pulse signal as
it
repeatedly connects and disconnects between 5V
voltage supplied from the engine control unit and earth.
TROUBLESHOONNG HINTS
Hint
1:
lf
unexpected shocks are
felt during driving or the
engine stalls suddenly during idling, shake the
crank angle sensor harness. lf this causes the engine to stall. poor contact of the sensor connector
is
suspected.
.
Hint
2:
lf the
crank angle sensor outputs a
pulse signal when the ignition switch
is turned ON (with rfie
engine not running), a faulty crank angle sensor or engine control unit is suspected.
Hint
3:
lf the
tachometer reads
0
r./min. when the engine that
has
failed
to
start is cranked, faufty crank
angle sensor
or
broken timing belt is suspecteä.
Hint
4:
lf the
tachometer reads
0
r,/min. when the engine that has
failed
to
start is cranked.
the primary
current of the ignition coil is not turned on and off.
Therefore,
troubles in the ignition circuit
and
ignition coil or faulty power transistor is
suspected.
Hint
5:
lf the engine can be run at idle even though the crank angle sensor reading is out of specification,
troubles are often
in
other than the crank angle sensor.
IExamples]
(1)
Faulty engine coolant temperature sensor
(21
Faulty idle speed control
servo
(3)
Poorly adjusted reference idle
speed
o
a
Control
relay
One
rotation of
crank angle sensor
O
Mirßrbidri moürtr
CorDorrtion
July 1992
PWUEqtl0.A