Without acceleration enrichment, when the throttle is abruptly opened the engine will briefly 'lean out'. To achieve good throttle response, acceleration enrichment is required. The following settings are available to control acceleration enrichment:
Asynchronous injection settings are also available under the Fuel Main menu.
The Accel Enrichment value is Accel Sens. x (TPS or MAP) Delta x Accel Cold Correction Table
Accel Mode is used to select whether the Acceleration Enrichment is activated by either a change in MAP or Throttle Position (TP(Main)). Selecting Accel Mode as OFF disables acceleration enrichment.
Note: Throttle position is the preferred method and should be used in all cases except when a suitable TPS is not available.
The Accel Sens. Table controls how much acceleration enrichment will be applied for a given rate of change of the value triggering the enrichment (either throttle position or manifold pressure depending on which Accel Mode is used). A larger Accel Sensitivity value will result in more acceleration enrichment.
There will always be some noise (unwanted electrical disturbance) in the MAP and TPS signal. To remove the possibility of this noise resulting in Acceleration Enrichment, the Accel Deadband can be used to specify the amount of rate of change required before enrichment is applied.
Example: If the Accel Mode is TPS and the Accel Deadband is 1 TPS %/100ms, then the throttle position must change by more than 1% per 100ms for any Acceleration Enrichment to be activated.
This function controls the rate at which the Acceleration Enrichment fuel decays away to zero. The number represents a percentage of the current Acceleration Enrichment which is removed from the Acceleration Enrichment at each injection event until Acceleration Enrichment equals zero.
Acceleration enrichment decay begins as soon as the new calculated accel enrichment value is less than the previous value. The number of injection events required to decay acceleration enrichment completely depends on the Accel Decay number and the Injection Rate. The Injection Rate depends on the Injection Mode and number of engine cylinders.
Example
If the original Acceleration Enrichment fuel was 4ms and the Accel Decay is 50% then the Acceleration Enrichment will decay as 4ms, 2ms, 1ms, 0.5ms, 0.25ms..... per injection event.
This means larger enrichments decay faster than smaller numbers.
During an engine's warm-up period more Acceleration Enrichment is required. The Accel Cold Trim Table allows acceleration enrichment to be adjusted with respect to engine coolant temperature. A value of 1.0 represents normal fully-warm acceleration enrichment and cells relating to fully warmed-up engine temperatures should be set to this value. At lower engine temperatures cell values larger than 1.0 will be required to provide additional acceleration enrichment.
The value in this table is multiplied by the Accel Sens. value and the appropriate Delta to get the new Accel Enrichment value.