Crank Angle Sensors
On Prelude models (TBI), the crank angle sensor consists of a combination TDC/Crank sensor mounted in the distributor housing. The ECU uses input from the crank pick-up coil portion of this sensor to help determine ignition and fuel injector timing for each cylinder. This sensor also furnishes an engine speed (RPM) signal to the ECU. The ECU uses the TDC pick-up coil portion of this sensor to initialize ignition timing upon start-up (cranking) and when crank angle signal is abnormal. See Fig 1 and Fig 2 .
In addition to the TDC and Crank pick-up coils inside distributor housing, Prelude models also utilize a CYL pick-up coil. The CYL portion of this sensor is utilized to detect TDC No. 1 position for triggering of sequential fuel injection. On Prelude models, this sensor is mounted on end of camshaft. See Fig 1 and Fig 2 .