Injection Pump Cam Signal (4X)

The pump cam signal is an optical device which generates one pulse per cylinder combustion stroke from a slotted disc mounted on the injection pump timing cam ring. The pulse is used to locate the start of injection event for each cylinder (i.e. timing) with respect to the crankshaft position sensor. The number one cylinder is identified with a wider pulse (larger slot in disc). The PCM uses this information to adjust idle fuel, timing, trigger real time events and is used in the diagnostics of the crankshaft position sensor and the high resolution circuit.