Injection Pump Cam Signal (4X)

The injection 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 rotor. The pulse is used to locate the start of the 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 in order to adjust the idle fuel and timing. The injection pump cam signal is used in the diagnostics of the crankshaft position sensor, and to identify cylinder misfires.