Mitsubishi Eclipse 1990-1998 Repair Guide

General Information

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See Figure 1

The ignition system found on the 2.0L and 2.4L engines is a distributorless type. The advance of this system, like the distributor type ignition system on the 1.8L engine, is controlled by the Engine Control Unit (ECU) or Powertrain Control Module (PCM). The distributorless ignition system contains a crank angle/position sensor which detects the crank angle or position to each cylinder and converts this data into pulse signals. These signals are sent to the ECU/PCM, which will calculate the engine rpm and regulate the fuel injection and ignition timing accordingly. The system also contains a top dead center sensor which detects the top dead center position of each cylinder and converts this data into pulse signals. These signals are then sent to the ECU/PCM, which will calculate the sequence of fuel injection and engine rpm. Both sensors are located in a common housing on the cylinder head opposite the timing belt side. The power and ground for both sensors is supplied by the ECU/PCM.



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Fig. Fig. 1: Distributorless ignition system components found on 1990-94 2.0L engines; others similar

When the ignition switch is turned ON , battery voltage is applied to the ignition coil primary winding. As the crank angle sensor shaft rotates, ignition signals are transmitted from the multi port injection control unit to the power transistor. These signals activate the power transistor to cause ignition coil primary winding current to flow from the ignition coil negative terminal through the power transistor to ground or be interrupted, repeatedly. This action induces high voltage in the secondary winding of the ignition coil. From the ignition coil, the secondary winding current produced flows through the spark plug to ground, thus causing ignition in each cylinder.

 
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