System Description

Fig. 1 Typical single point electronic fuel injection (EFI) system components. Front wheel drive with 2.2L engine:

Fig. 6 Logic module & automatic shutdown (ASD) relay replacement:

Fig. 7 Power module replacement:

This system, used on 1984-85 front wheel drive models with a 2.2L engine, is a computer-controlled, single-point fuel injection system which provides a precise air/fuel ratio under all driving conditions. The system utilizes a logic module, a digital pre-programmed computer, to regulate ignition timing, idle speed, emission devices and air/fuel ratio. The logic module is located on the right front kick panel.Fig. 6

Various sensors and switches located throughout the vehicle provide information to the logic module, Fig. 1. All inputs to the logic module are converted to signals sent to the [1][2]power module. The power module is located on the left front fender well.Fig. 7 According to these signals, the power module changes fuel flow at the injector and/or ignition timing.

The logic module tests many of its own input and output circuits. If a problem is detected in a major system, the information is stored in the logic module. This information can be displayed by a flashing light emitting diode (LED) located on the module, or by connecting a diagnostic readout and reading a numbered display which corresponds to a specific problem.

The following is a sequence of the system operation:

1. Turn the ignition switch to ON, battery voltage (J2) is supplied to the [1][2]power module. The power module sends 8 volts to the distributor pickup and the logic module. The logic module then sends 5 volts to the coolant temperature sensor, throttle sensor and the MAP sensor. The power module sends fused (J2) refer to Fig 1, to the logic module and the auto-shutdown relay.

2. Turn the ignition switch and "crank" the engine. The distributor sends pulses to the [1][2]power module and the logic module. Power module grounds ASD relay coil and pulls relay in. The ASD relay feeds battery voltage to the In-Tank fuel pump, logic module, ignition coil (positive) and the power module (injector and ignition coil drive). The logic module then receives information from the coolant temperature sensor, throttle sensor, MAP sensor and distributor pickup. The AIS motor is driven open by the logic module using fused J2. The logic module then sends information to the power module, ignition control and injector control. The power module must have the distributor pulse within one half of a second after cranking or ASD will not be grounded. The power module then receives the commands from the logic module and then it drives the injector to supply fuel and triggers the ignition coil (negative).

3. After releasing the key to "RUN" the following information must be available to the logic module and the [1][2]power module or the engine will stop.

a. The logic module inputs are system ground, 8 volts and distributor signal. The logic module outputs are sensor ground, sends 5 volts to the MAP sensor, throttle sensor and the coolant sensor. The injector control and ignition control.

b. The [1][2]power module inputs are J2 voltage, injector return, switched battery voltage, injector control, distributor signal and ignition control. The power module outputs are ignition coil (negative), fused J2, injector driver, ASD relay control and 8 volts.

c. Auto shutdown relay inputs are battery voltage, fused J2, relay control. The auto shutdown relay outputs are switched battery voltage.

d. The distributor pickup inputs are 8 volts and signal ground. The distributor pickup outputs are RPM signal.

Throughout the operation of the engine, sensors supply information to the logic module which in turn controls ignition (spark advance), fuel delivery, and idle speed.

4. Turn the ignition key to the "OFF" position, make sure the J2 is removed from the [1][2]power module, the fused J2 is removed from the auto shutdown relay, the ASD relay contacts are open and battery voltage is removed from the In-tank Pump, the logic module, the ignition coil (positive) side and the power module.