Setting BISS and ISC Range

[Besso]

According to the Vfaq http://www.vfaq.com/mods/BISS-1G.html

You want the ISC in the middle of it's range, while adjusting the BISS for optimal setting (Galant VR-4 idle should be 800 RPMs). But what exactly is the middle of it's range? If you log it, I think it goes anywhere from 0-100+. Does anybody have hard evidence on where it should properly be set @ idle with a logger using MMCD? Should it be set closer to 0 or 50? WTF

 

[doggo]

That number you are refering to is just a command value TO the ISC. It's not the a certain reading of actual position; the ISC has no feedback signal to the ECU. It just goes where the ECU tells it.

With the BISS properly set via grounding the diagnostic pin of the ECU, which disables the ISC, you should be seeing about 750 RPM. Then removing the ISC ground, the ISC should 'come on' and adjust RPM for a few minutes and it should eventually be getting an ECU command of around 40-60 with RPM again around 750.