Hi Mike,
I have no experience with PST engines but am somewhat familiar with FADEC software.
The amount of fuel during ramp up is primarily controlled by two parameters: PUMP START POINT and PUMP START RAMP. As the name implies PUMP START POINT sets the power of the pump at the beginning of the fuel ramp, this also defines the minimum pump speed. PUMP START RAMP defines the rate of fuel increase during the ramp phase.
For PUMP START POINT, AUTO+3 seems a little high. Most of my engines are at +1 or +2. If you reduce that setting then you will have less fuel throughout the ramp phase. Since it runs fine at the beginning of the ramp phase then that value is probably OK for your set up.
To keep the same amount of fuel at the beginning of the ramp phase and have less towards the end you should reduce PUMP START RAMP. Try reducing it in steps of 002 until you have no flames. If you get to the point where it takes too long to get to idle then you should increase the value. Since you're experiencing popping, you may have a clogged injector or something else going on in the engine that is affecting your starts.
By the way I still have both of my Enforcers, Byro-Blaster and Turbine but rarely fly them any more in favor of my newer jets.
Good Luck,
Joe