2-wire IACV with an OBD2B ECU ?

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Installing a D16Y8 motor (96 Civic EX, vtec, obd2a) into a 99 DX hatch (had a D16Y7), and have not added the vtec wiring yet. Using the D16Y7 engine harness and D16Y7 distributor currently.

I was under the impression that I could rewire the 2-wire IACV to work with the 99 DX ECU (which had a 3-wire IACV), but when I try it has idle issues with the IACV wire in the ECU B plug pin 6 or pin 23 (I pulled pin 15 when I re-wired). In pin 6, it idles high and hunts around. In pin 23, it acts as if the IACV is unplugged and will not idle, but seems to run fine otherwise.

Now I think I have to use the 96 EX ECU in order to get the 2-wire IACV to run right, which means buying a jumper harness to adapt the obd2b wiring to the obd2a ECU.

Is that correct, or do I have other options, or am I completely mis-guided and making even more bad decisions that I already have?
I installed the harness to adapt the obd2b wiring to the obd2a ECU and it idled perfectly. The IACV must be working!