Mitsubishi Stealth 1994 Import Service Manual page 540

MULTIPORT FUEL INJECTION -
CRANKSHAFT POSITION SENSOR <SOHC>
5
OPERATION
The crankshaft position sensor senses the crank angle (piston position) of each cylinder, converts it into a
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pulse signal and inputs it to the engine control module, which then controls the engine speed and controls
the fuel injection timing and ignition timing based on the input signal.
Power to the crankshaft position sensor is supplied from the MFI relay and is grounded to the body. The
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crankshaft position sensor generates a pulse signal as it repeatedly connects and disconnects between 5
V voltage supplied from the engine control module and ground.
TROUBLESHOOTING HINTS
Hint 1: If unexpected shocks are felt during driving or the engine stalls suddenly during idling, shake the
crankshaft position sensor harness. If this causes the engine to stall, poor contact of the sensor
connector is suspected.
Hint 2: If the crankshaft position sensor outputs a pulse signal when the ignition switch is turned ON (with
the engine not running), a faulty crankshaft position sensor or engine control module is suspected.
Hint 3: If the tachometer reads 0 rpm when the engine that has failed to start is cranked, faulty crankshaft
position sensor or broken timing belt is suspected.
Hint 4: If the tachometer reads 0 rpm 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 ignition power transistor is suspected.
Hint 5: If the engine can be run at idle even though the crankshaft position sensor reading is out of
specification, troubles are often in other than the crankshaft position sensor.
[Examples]
(1) Faulty engine coolant temperature sensor
(2) Faulty idle air control motor
(3) Poorly adjusted reference idle speed
1
Output characteristic
On-Vehicle Inspection of
MFI relav