C 3500 Truck 2WD V8-454 7.4L VIN J SFI (1999)
Crankshaft Position Sensor: Description and Operation
Crankshaft Position Sensor-1
The Crankshaft Position Sensor (CKP) is located in the front engine cover and is perpendicular to the crankshaft target wheel. The air gap between the
sensor and the wheel is preset and not adjustable. The target wheel has 4 slots 60 degrees apart and is keyed to the crankshaft. As the target wheel
rotates, the slots passing by the sensor create a change in the magnetic field of the sensor which results in an induced voltage pulse. One revolution of the
crankshaft results in four pulses (4x signal). Based on these pulses, the VCM is able to determine crankshaft position and engine speed. The VCM then
activates the fuel injector and provides a spark to the distributor. The relation between the crankshaft position sensor and the target wheel is crucial. The
sensor must be exactly perpendicular to the target wheel with the correct air gap.
