Cutlass Supreme V6-3100 3.1L MFI VIN M (1994)
Crankshaft Position Sensor: Description and Operation
GENERAL INFORMATION
This engine uses two crankshaft position sensors. One sensor, mounted on the side of the engine block (3X crankshaft sensor), and another (24X
sensor) mounted on the front of the engine behind the harmonic balancer.
3X Sensor
Crankshaft Position Sensor Installation
PURPOSE
The 3X crankshaft sensor provides crankshaft position and engine speed information to the ignition module and control unit. The signal indicates
the exact position of the crankshaft once each revolution, and the relative position every 60° thereafter. This signal is used as a reference for fuel
injection, ignition timing, and engine speed calculations.
OPERATION
This 3X crankshaft sensor is hall-effect sensor mounted on the side of the engine block. This sensor protrudes into the block, within approximately
.050" of the engine crankshaft reluctor wheel. The reluctor is a special wheel cast into the crankshaft with seven slots machined into it, six of
which are evenly spaced 60~ apart. A seventh slot is spaced 10° from one of the other slots and serves to generate a "sync pulse," indicating the
exact position of the crankshaft once each revolution. As the crankshaft rotates, the slots in the reluctor wheel cause changes in the magnetic field
of the sensor, turning the switch "OFF" and "ON" to produce a pulse that is easily measured.
By measuring the time between pulses, the DIS module can recognize the pulse representing the seventh slot or "sync pulse." Based on this "sync
pulse," the DIS module sends a reference signal to the ECM to calculate crankshaft position (used to fire the ignition coils in correct sequence) and
engine speed.
24X Sensor
24X Crankshaft Sensor Installation