Precision Turbo and Engine BigStuff3 GEN3 PRO SEFI System Hardware & BigComm Software - Manual (Page 93)

BigStuff3 Pro SEFI System
Version 2.1 – February 2011 86
The first entry of the dMAP Parameter Configuration table is Asynchronous Acceleration Enrichment
(AAE). It is used to set the MAP transient fuel thresholds relative to MAP (kPa) and TPS (%) values.
Below, is a brief description of each.
 MAP Limit: Establishes the MAP value in kPa at which the dMAP transient fuel is disabled.
For example, if the MAP Limit value is set to 80 kPa, the dTPSdt transient fuel will be disabled
above MAP values of 80 kPa.
 TPS % Clip: Establishes the TPS value, as a percentage, at which the dMAP transient fuel is
disabled. For example, if the TPS % Clip value is set to 80 %, the dMAP transient fuel will be
disabled above TPS values of 80 %.
The second entry of the dMAP Parameter Configuration table is Deceleration Fuel Cut Off (DCFO). It
is used to calibrate when the Base Fuel Map pulse width fuel is turned off and on relative to MAP
(kPa) values. Below, is a brief description of each.
 DCFO On: Establishes the MAP value in kPa at which the Base Fuel Map pulse width is
momentarily disabled. It is used to calibrate deceleration drivability. For example, if the DCFO
On value is set to 30 kPa, the base pulse width will go to zero, 2.5 seconds after falling below a
MAP value of 30 kPa, with the throttle closed. The Base Fuel Map pulse width is turned back
on based upon the DCFO Off value (see DCFO Off).
 DCFO Off: Establishes the MAP value in kPa at which the Base Fuel Map pulse width is re-
enabled. It is used to calibrate deceleration drivability. Typically, the DCFO Off value is set to
5 kPa above the DCFO On value. For example, if the DCFO On value is set to 30 kPa the
DCFO Off value should be set to 35 kPa. Once the MAP value exceeds 35 kPa, the Base Fuel
Map pulse width is turned back on.
The third and final entry of the dMAP Parameter Configuration table is Acceleration Enrichment (AE)
Temperature. It is used to disable the affect of the Run Time Correction multiplicative scalar value has
on the Positive dMAP Correction and dTPS Transient fuel values relative to an engine coolant
temperature (deg F). Below, is a brief description of the AE Temperature “Run Temperature” setting.
Run Temperature: Establishes the engine coolant temperature in deg F at which the Run Time
Correction multiplicative scalar term no longer influences the Positive dMAP Correction or TPS
Transient fuel values. Therefore, if the Run Temperature value is set to 120
o
F, the Run Time
Correction multiplicative scalar term will no longer influence the Positive dMAP Correction or TPS
Transient fuel values at engine coolant temperatures above 120
o
F.
To change a value in these tables, move the cursor using the PC’s mouse or arrow keys to the cell to be
changed and input the desired value. Then click on OK to save the changes.
TPS Transient Fuel
The TPS transient fuel control is comprised of 2 primary tables. Each of the table’s play an integral
role as to how the TPS Transient Fuel requirements are calibrated for abrupt throttle changes that
causes the engine to accelerate. TPS transient fuel is asynchronously injected relative to a rate of
throttle change (dTPSdt). The asynchronous pulse can be modified relative to the throttle position