Federal Spec. Vehicles

PURPOSE
The engine rpm signal is produced by the NE pickup coil located in the distributor. The G pickup coil, also located in the distributor though separate, works in conjunction with NE pickup coil and produces an output pulse to the engine control module (ECM). The ECM uses this signal to determine engine speed and relative top dead center for each cylinder.

OPERATION
The NE coil detects the engine rpm and the G coil detects the camshaft position. Whenever the engine is rotating, a pulsed signal is returned to the ECM. As engine speed increases the frequency of the signal increases as well. Using the NE signal coupled with the signal of the G pickup coil, exact piston position can be determined by the ECM.