Cherokee 2WD L4-150 2.5L VIN P MFI (1991)
Camshaft Position Sensor: Description and Operation
Sync Signal Generator and Pulse Ring
Sync Signal Generator Operation
The sync signal generator is located in the distributor housing under the ignition rotor and pulse ring. The sync signal generator is used to reference
number 1 and 4 cylinders, it sends voltage to the engine controller and works in conjunction with the Crankshaft Position Sensor (CPS) so that the engine
controller can establish and maintain the correct injector firing order.
The sync signal generator consists of a hall effect switch and a pulse ring that is mounted to the distributor shaft. As the leading edge of the pulse ring
passes the hall effect switch, the change in the magnetic field induces a voltage rise of 5 volts. This 5 volt signal indicates to the engine controller that
the next piston to come to TDC is number 4. When the trailing edge of the pulse ring leaves the sync signal generator, the collapse of the magnetic field
causes the voltage to drop to 0 volts. A signal of 0 volts indicates to the engine controller that piston number 1 is the next piston to reach TDC.
The signal from the sync signal generator combined with the input signal from the Crankshaft Position Sensor (CPS), are what the engine controller uses
to properly synchronize injection.
