Ignition

Ignition System Components:

This ignition is based on the fully electronically controlled Bosch ignition system with knock control (EZ-K). The ECU (located under instrument panel above pedal assembly to the left) uses electrical input signals from various devices and sensors to calculate the engine load and condition. With this information the ECU will adjust the ignition timing to provide optimal performance, driveability and emissions output.

Input devices (the ECU receives):

^ Ignition switch signal.
^ Crankshaft position and speed signal.
^ Knock signal.
^ Coolant temperature signal.
^ Air mass meter signal from fuel injection control unit.
^ Throttle position signal.
^ No. 1 cylinder signal.

Output devices (The ECU controls):

^ Power stage.
^ Engine speed signal to the fuel injection control unit (fuel injection ECU input device).

Three-Dimensional Ignition Map:

TIMING PROGRAM:
The control unit is programmed with a series of specific settings for a number of defined speeds and engine loads. These settings are stored in the ECU as an "ignition map". This means the timing can be controlled to the accuracy of a fraction of a degree. The ignition ECU will adjust the timing according to this "ignition map" at all times under all engine loads (except engine knock).

ANTI-KNOCK PROGRAM:
Knock causes high and dangerous combustion temperatures. The ignition system will retard the timing in approx. 3° increments (to a maximum of 15°) to reduce knock.
When the knock problem has been eliminated, the ignition ECU will advance the timing in 0.37° steps until the normal setting has been restored or knock reoccurs.

RPM LIMITER PROGRAM:
At approx. 6300 RPM the ignition is interrupted to keep the engine from overrevving.

STANDING CURRENT PROTECTION FUNCTION:
To avoid overheating the coil when the ignition is ON and the engine off, a separate circuit interrupts the current to the coil. The ECU uses the engine speed and position signal to determine if the engine is running or at rest.