The idea is simple. At 68 degrees F, the air temp gauge reads about 2k to 3k resistance. So we simply place a 2k to 3k resistor across the ECU wires to fool the ECU.
Pictured is ST165 ECU
E2 = White wire with black stripe
THA = Gray wire
If you have the ECU pinouts for ST185 that would be helpful. Basically just look up in a manual the wires for THA and E2.
Keep in mind that in order to prevent the ECU from reading the air temp from the actual sensor, you will need to cut the THA wire after the resistor connection. Remember that cars have air temp sensors for a reason, and doing this mod could cause poor operation especially in cold air temperatures. This modification is best for warm climates or situations such as track racing day where every edge is needed.
This mod will also work for any other toyota flapper style AFM. Such as MR2 turbo and non, MK3 Supra non turbo, MK2 supra, Corolla, and Non turbo Celica.