Models With EFI & Turbocharger

Fig. 2 Ignition system wiring schematic. 1987 - 88 Sprint w/EFI & turbocharger:

The electronic ignition system used on 1987 - 88 models with EFI and turbocharger, Fig. 2, incorporate the same components as the ignition system used on carbureted models but also incorporate an igniter, with a knock controller which electrically controls ignition timing, a knock sensor and an Electronic Control Module (ECM) to extend engine performance and /or protect the engine.
The igniter with knock controller type system, operates in the same manner as an ordinary electronic ignition system when no engine knock is present. When knocking occurs, the system controls the ignition timing according to to the degree of knock based on the signals from the knock sensor, up to 12° of crank angle. In other words when knocking occurs, the system retards the ignition timing to suppress knocking.



Distributor
The distributor incorporates a rotor, signal generator, vacuum advance unit and a centrifugal advancer which controls ignition timing. The throttle body bore and surge tank internal pressure is delivered into the vacuum advance unit through hoses. When the pressure is negative (vacuum), it moves the breaker clockwise (reverse of rotor rotation) thus advancing ignition timing. Positive pressures cause the breaker to move counterclockwise, retarding ignition timing.

Igniter With Knock Controller
The igniter knock controller is installed in the left side of the engine compartment. It has two main circuits. One serving as a full transistorized igniter and the other as a knock controller. Based on the engine speed and signals from the ECM and knock sensor, the knock controller gives the igniter an instruction to retard the ignition timing to suppress engine knock. Engine speed is automatically detected by the detection circuit in the controller. The controller also has a built-in failsafe circuit which gives instructions to retard ignition timing by a certain degree for the suppression of engine knock should the knock sensor fail or a short or open occur in the output leads.

Electronic Control Module (ECM)
When the ECM detects that the turbocharger is operating and the knock control system is in effect, the ECM lights the ``Turbo'' lamp.
Knock Sensor
The knock sensor is located on the intake manifold side of the cylinder block. This sensor detects engine vibrations, then converts these vibrations into an electrical signal and transmits this signal to the igniter with knock controller. The tightening torque of the knock sensor affects its performance. Ensure knock sensor is torqued to 15.5 - 18 ft. lbs.