AEM 30-6905 Universal Programmable EMS-4 - Manual (Page 178)

Page 178 of 279 EMS-4 Install and Tuning Guide_Rev 1.6
Acceleration Fuel Function Options
Accel TPS Sensitivty – The larger this number, the larger the calculated Accel dTPS value will
be for a given change in throttle position. Determines how sensitive he accel fuel function is to
changes in throttle position.
Accel dTPS Trigger – The calculated Accel dTPS value must be higher than this number for
the accel function to activate. Used as a filter to eliminate false triggering from normal signal
noise.
Accel Limit – Used as a clamp for the accel fuel function. If the calculated accel fuel modifier is
greater than this value, the modifier is clamped at this setting.
Accel Pump Sustain – Controls the rate at which accel fuel goes away. Actual formula used is
current accel fuel % times this number calculated each engine revolution. A larger number
makes the accel fuel trim stay active longer.
Tuning Throttle Accel
The operating principle is pretty standard. When the throttle is moved, the Accel dTPS value is
calculated. It gives a number proportional to the rate of change of the throttle. If this value is
above the user-specified threshold Accel dTPS Trigger option, then the acceleration pump is
enabled. But, since the TPS signal is usually noisy, the accel pump would be triggering all the
time. So we need to filter it before the threshold test is performed. The filter specification can be
set with the Accel TPS Sensitivty option.
Once an Accel dTPS value is generated, the corresponding accel pump size is looked up from
the Accel vs dTPS table.