Ignition

Ignition System And Components:

This ignition is based on the fully electronically controlled Bosch hall-effect ignition system with knock control (EZ-K). The ECU, located under instrument panel (above gas pedal to the right), 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 (hall-effect) signal.
^ Knock signal.
^ Air mass meter signal from fuel injection control unit.
^ Throttle position signal.
^ A/C control signal from climate control panel.
^ A/C pressure sensor signal.

Output devices (The ECU controls):

^ Power stage.
^ Engine speed (RPM) signal to the fuel injection control unit (fuel injection ECU input device).
^ Knock signal to the fuel injection control unit (fuel injection ECU input device).
^ Crankshaft position and speed (hall-effect) sensor power supply (12V).

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 first retard the timing in approx. 2.8° increments (to a maximum of 9.8°) to reduce knock. If knock persists, the fuel injection system will provide a richer air/fuel mixture to eliminate the knocking problem.
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 excess RPM the ignition is interrupted to keep the engine from overrevving.

OVERHEAT PROTECTION PROGRAM:
When the engine coolant rises above safe operation temperature, the ignition ECU will advance the timing by 13° if at idle.

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.