Operation CHARM: Car repair manuals for everyone.

Inputs and Outputs

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 6 cylinders, it sends voltage signals to the ECU so that it 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 ECU that the next piston to come to TDC is number 1. 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 ECU that piston number 6 is the next piston to reach TDC.

The signal from the sync signal generator combined with the input signal from the engine speed sensor (CPS), are what the ECU uses to properly synchronize injection.