m20 ITBs and idle control valve idle issue

[zaq123]

Ok so I got ITBs idling nicely with the idle valve ICV blocked off. Opened ICV port, car is idling good, blipped the throttle and idle hangs up on high. Closing ICV port with my finger brings idle back to normal. Remove finger and it continue to idle normal until the throttle is blipped again.

Any ideas what's happening ?

[2mAn]

A pic wont help but I would appreciate it...

I want ITBs

[zaq123]

A pic wont help but I would appreciate it...

I want ITBs

There are some pics in post linked below and some under under Media tab in my user profile.
I learned the cyl head was cracked (was never pressure tested by machine shop before rebuild). So here are am back with new cyl. head a year later lol

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/10135120-m20-crankcase-pressure

https://www.r3vlimited.com/board/forum/general-forums/general-discussion/10134574-questions-about-diy-full-respray-paint-job/page2

https://www.r3vlimited.com/board/forum/e30-technical-forums/engine-drivetrain/m20/10134293-m20b28-itb-stroker-build-h-b-327s-head-195whp?p=10134317#post10134317

https://www.r3vlimited.com/board/forum/e30-technical-forums/general-technical/10132802-central-locking?p=10133488#post10133488

[MrBurgundy]

could be some binding on the plates? Maybe when you block off the icv port the vacuum is bumped up enough to suck em back.

[digger]

when it is hanging try closing the throttle lever by hand against the idle stop. you might need a stiffer return spring.