DeVille V8-4.6L VIN Y (1998)
Crankshaft Position Sensor: Description and Operation
Description
Crankshaft Sensors
The two crankshaft sensors are located on the front bank (BANK 2) of the engine block between cylinders 4 and 6. Crankshaft position A sensor is
located in the upper crankcase and crankshaft position B sensor is located in the lower crankcase. Both sensors extend into the crankcase and are sealed
to the engine block with O-rings. The crankshaft position sensors are not adjustable. The magnetic crankshaft position sensors operate similar to the
pickup coil in a distributor. When a piece of steel (called a reluctor) is repeatedly moved over the sensor, a voltage will be created by the sensor that
appears to go On-Off-On-Off-On-Off. This On-Off signal is also similar to the signal that a set of breaker points in a distributor would generate as the
distributor shaft turned and the points opened and closed.
Reluctor Ring
The reluctor ring is cast onto the crankshaft between the #3 and #4 main bearing journals. The reluctor ring has 24 evenly spaced notches or air gaps and
an additional 8 unevenly spaced notches for a total of 32.
Operation
As the crankshaft makes one complete revolution, both the A and B sensors will produce 32 On-Off pulses per revolution. In addition, the A sensor is
positioned 27 degrees of crankshaft revolution before the B sensor. This creates a unique pattern of On-Off pulses sent to the ignition control module so
that it can recognize crankshaft position.
