Prelude L4-2.2L SOHC (1994)
Crankshaft Position Sensor: Description and Operation
Top Dead Center/Crankshaft Position/Cylinder Position Sensors
PURPOSE
The TDC/CKP/CYP Sensor is used to determine ignition timing at start-up, position of #1 cylinder for sequential fuel injection, normal timing for
fuel injection and ignition of each cylinder and also detects engine RPM.
OPERATION
The unit is made up of three separate sensors mounted inside the distributor. The Top Dead Center (TDC) Sensor, the Crankshaft Position (CKP)
Sensor, and the Cylinder Position (CYP) Sensor. All three sensors are pickup coil and reluctor construction. The Programmed Fuel Injection
Electronic Control Module (PGM-FI ECM) uses these signals to determine fuel injector and ignition timing and to calculate engine RPM.
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The TDC sensor signal is used to determine ignition timing at engine start-up. This signal is also used as a backup signal in the event the CYP
sensor signal becomes abnormal.
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The CYP sensor generates a signal based on the position of the number #1 cylinder for proper timing of the sequential fuel injection system for
each cylinder.
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The CKP sensor determines timing for fuel injection and ignition of each cylinder and also detects engine speed.
