CIS-Eiii

Ignition timing is determined according to values which are programmed in the ignition control unit.
The ignition timing is basically determined according to:

ENGINE SPEED - From the Hall sender
ENGINE LOAD - From the air sensor potentiometer

The ignition timing will be advanced as engine speed increases. The amount of advance will be reduced, however, as engine load increases.
Two separate ignition maps are programmed into the control unit's memory. One map is designed for operation with regular fuel and the other with premium fuel.
The engine will develop the same horsepower when operated with either ignition map. However, when the premium fuel ignition map together with premium fuel is used, the engine will develop greater torque at a lower engine speed.

REGULAR FUEL
IGNITION MAP





ENGINE OUTPUT WITH REGULAR FUEL
- 130 hp at 5600 RPM
- 138 ft./lbs. at 4500 RPM

PREMIUM FUEL
IGNITION MAP





ENGINE OUTPUT WITH PREMIUM FUEL
- 130 hp at 5600 RPM
- 140 ft. /lbs. at 4000 RPM





IGNITION MAP SELECTION
The ignition control unit switches automatically to the premium fuel ignition map whenever the engine coolant temperature is above 149°F (65°C). This map has ignition timing values that are slightly more advanced in some areas of operation than the ignition map for regular fuel. If ignition knock (detonation) occurs repeatedly, the ignition control unit will then switch to the ignition map for regular fuel.
The ignition control unit will automatically switch back to the premium fuel map after a fixed amount of time or whenever the engine is restarted.

IGNITION KNOCK REGULATION
If a cylinder develops ignition knock, the ignition control unit will sense this through the knock sensor mounted on the engine block. The control unit will then retard the ignition timing 3.4° for that cylinder. If the knocking stops, the ignition timing will be advanced in steps of 0.54° back to the pre-programmed value.
If the knocking continues or reoccurs, the ignition timing can be retarded up to 12° for each cylinder.