The logic module uses this sensor to determine the position of the camshaft. It sends a pulse when cylinder #1 is currently being "referenced" by the ignition reference sensor. This information is used to determine which pulse from the ignition reference sensor refers to which cylinder so that it knows which fuel injector bank to fire. The fuel injector sync pickup sensor uses a hall effect sensor that is located beneath the distributer cap which senses the presence of a permanent magnet on the other side of a rotating "shutter" that is attached to the rotor. The sensor has an open collector output that is pulled up to 8V by the logic module. Each time the hall effect sensor detects the magnet (when cylinder #1 is being referenced), the output is pulled down to 0V. The shutter has 1 opening, so there is one "low" pulse for each rotation of the distributer rotor and the camshaft, and 1 pulse for every 4 rotations of the crankshaft (for 2.2L and 2.5L).
If the logic module receives a signal from the ignition reference sensor without any signal from the fuel injector sync pickup sensor, a fault code 54 is stored. The 1985 logic module will turn on the power loss light and enter limp-in mode. The logic module will then guess at injector timing and any signal from the detonation sensor will apply to all cylinders. For all other model years, the engine will stall or not start.
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Copyright © 1996-2003 Russ W. Knize.