Mirage L4-1597cc 1.6L DOHC Turbo (1989)
Top Dead Center (TDC) Sensor: Description and Operation
Crank-Angle And Top Dead Center Sensor
The Crank Angle Sensor and the Top Dead Center Sensor are located within the housing. These sensors are incorporated into one unit, being a disc and a
pick-up unit. The disc is affixed to the main shaft and the light-transmitting unit is mounted stationary to the housing.
Crank Angle And #1 TDC Sensor
The disc contains 4 large slits around its circumference to indicate the crankshaft angle. An additional light-transmission slit located inward from the
edge is used to indicate number one cylinder's top dead center position. The pick-up unit assembly uses two luminous diodes and two photo diodes, in
order to detect the two different slits. There is a very slight clearance between the luminous diodes and the photo diodes, and the disc rotates within this
space.
Crank Angle And #1 TDC Sensor Circuit
As the distributor shaft rotates the slits at the discs edge pass between the light and the optical reading part of the unit. The light emitted from the
luminous diodes pass through the slits to the photo sensing diodes. When the photo diodes receive the light, they become conductive and generate a
signal, which is sent to the Control Unit.
The Control Unit is able to detect number one cylinder TDC by the signal generated through the single inner slit on the disc. The sequence of the fuel
