Important Note
Do not use the air and water temperature compensation to compensate for poor running resulting from other problems. Also note that changes made to the air and water temperature compensation tables do not take effect until the ignition is switched off, engine re-started and run for several minutes.
Air Temperature Compensation
This allows the ignition advance compensation by air temperature to be adjusted. The stock behaviour is to retard the ignition timing as the intake air temperatures increases.
Water Temperature Compensation
This allows the ignition advance compensation by coolant temperature to be adjusted. The stock behaviour is to advance the ignition with lower coolant temperatures to offset the slower mixture burn rate.
Throttle Tip-In Compensation
Note: Normally only the Gear Adjustment table needs to be altered. To increase the amount of ignition retard upon tip in, increase the value in the Gear Adjustment table (to a maximum of 100). To reduce the amount of ignition retard, decrease the value in the Gear Adjustment table (to a minimum of -100).
Ignition timing is retarded upon throttle tip in to prevent detonation. The retard amount is dependent on the rpm, gear, throttle position and rate of throttle position change.
The base equation is: Ignition Retard = Base Retard x Throttle Position Adjustment x Gear Adjustment
Base Retard
The base ignition retard is determined by engine speed. This number is degrees of retard.
TPS Adjustment
The base retard is then adjusted by the position of the throttle. Since this is an adjustment, a value of 0 does not change the base ignition retard; a negative value will reduce the amount of ignition retard and a positive value will increase the amount of retard.
Gear Adjustment
The ignition retard is then adjusted by gear. Again, a value of 0 does not change the ignition retard; a negative value will reduce the amount of ignition retard and a positive value will increase the amount of retard.
Retard Duration
Finally the retard duration determines how long the ignition is retarded upon tip-in. The ignition timing is ramped back up to the normal value, so the duration is a measurement of the total length of retard.
Ignition Dwell Angle
The ignition dwell angle determines the amount of time the ignition coil charges before discharging to the spark plug. Up to a point, a longer charge time will result in a higher voltage spark.
Note that increasing the coil charge time will increase the temperature of the coil. This is an advanced table - only change if you are sure of the effects.
Dwell Angle
This table sets the coil dwell angle in camshaft degrees. The maximum dwell angle time is about 65 degrees, which is approximately 75% of the available 90 degree window between cylinder events.
Voltage Compensation
This table compensates the dwell time based on battery voltage. Since the ignition coil will provide a higher voltage spark when the battery voltage is higher, the dwell angle can be reduced. The converse is true when the battery voltage is low.
Also see Fuel Compensation Parameters