Converted to P&H injectors, now have issues :-(

[beetos]

My system was running perfectly on hi impedance injectors connected to the gray harness.
I subsequently changed injectors to low impedance running directly off the ECU (it has P&H drivers), and at the HSF3, I disconnected the green wire of the gray harness, and instead used the green harness green/red wires to connected to injector -/+.

I am seeing an IDC pulse, but the only way the system even begins to respond is if I use a 2.75 pre-amp. Also with the threshold turned quite low, it only begins water injection at around 48% duty cycle looking at logs, and the flowmeter no longer nicely tracks IDC like it did with the high impedance injectors.

What am I doing wrong? is there some links/soldering to do on the board? I have the version 3.1 red board, currently I have the MPS link soldered and the MPS>2 link soldered.

Thanks