The bit about the Idle control isn't true. The wiring of the 4 coils *does* matter. The idle control uses a 'stepper' motor, meaning each of the 4 coils can only govern so much of the travel of the coil's 30 some odd steps. If you wire the coils in incorrectly the ecu potentially loses the ability to actually move the motor.
For example, let's say to open up the idle control the ecu has to fire the 4 coils in order, 1, 2, 3, 4. If you swap two of the coils, let's name them "B1" and "B2" in this example, and the ECU actually ends up firing the coils in the order 1, 2, 4, 3, the motor will be stuck between steps 1 and 2 because it will trigger 4 when it is too far away (at position 2) and when it loops back around for 1, the ISC will actually go in reverse to 1, and then back to 2 again.
wiki
Several people, myself included, had it wired the way the diagram shows it with no luck. It won't burn anything out, as there is still coil resistance on every wire, but it won't be able to do much with idle. All of us were having issues with idle being around 2000-2500 and the problems instantly went away when the coils were switched.
With all of that said, I'm not sure where people are finding the coil control for coils "B1" and "B2" are switched on '90 ECU outputs. I've used a '90 ECU in my cars for extended periods of time and never had any issues with idle control, and I've never heard of anything about needing to switch more than pins 6 and 14 around. This surely would have been covered by Keydiver or one of the other DSM ECU experts out there if it was true. Maybe part of the confusion is just the names of the 4 coils? I could call them coils 1, 2, 3, 4 or A, B, C, D for that matter. I don't think that means you can trust a wiring diagram for one car or another to actually mean anything when they mention coil "B1". In
this diagram, the author just referred to the coils as "1, 3, 4, 6", although this is arguably more correct since it probably refers to the pinout of the ISC motor.
Brox, when you say the MAF is $50, where are you finding it for that price? EvoM?