Edelbrock Pro-Tuner, User Manual

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In Speed/Throttle (Alpha-N) mode or Speed/Density mode, there is the ability to adjust a
global trim for spark advance based upon MAP. This can be useful if ignition
characteristics change greatly with ambient air pressure. While not often needed, the
MAP Spark Trim table can be helpful in providing a global spark retard for a very hot
intake charge in order to help avoid detonation.
Tips for tuning:
The table is an offset to the main Spark Advance map. It is based on manifold pressure
in KpA or in-Hg. (Whichever you have chosen as your desired units of pressure in the
application settings.) A value of "0" means that no change is being applied to the base
map. Enter the values in degrees positive (more advance) or negative (less advance).
Keep the values small. If a large value is required, it probably means that your base
spark advance calibration is not optimized, and you should adjust the main spark map
further with a representative charge pressure.
NOTE: This table is not recommended to
be used in Speed/Density mode as the control algorithm accounts for pressure changes
automatically.
O2 Equiv Ratio Delta Table (Pro Option Only)
The O2 Equiv Ratio Delta Table may sound complex, but it really is not. The function
of this table is to define part of the criteria for going into closed loop operation. There are
several conditions that need to be met in order for the engine to go into closed loop
operation and perform any adaptation. The engine coolant temperature must reach a
predefined level, the warm up cycle must be complete, and the engine must be in a
steady state operating condition. In addition to these conditions, the desired Air/Fuel
ratio commanded by the user must be within a certain band of stoichiometric (14.7:1
with gasoline). This is because the user may want to disable closed loop operation at
some loads, or narrow the band (particularly at idle) because a standard switching
oxygen sensor can become inaccurate and lazy at low flows and exhaust temperatures;
allowing a switching sensor to have a wide band of authority will cause deterioration of
the calibration as the system tries to adapt fueling based on those inaccurate values.
The table is ordinated as a function of throttle position in percent. The cell values entered
represent a band
in equivalence ratio from stoichiometry. The stoich value for a given
fuel is 1.000 A higher value such as 1.040 is richer than stoich and a value of less than
1.000 like .992 is leaner than stoich.