I have searched and can't find the exact answer to my question although I have found some good info pertaining to adjusting BISS and replacing the iacv motor. So wanted to ask here to see if anyone can give me info on how long iacv tables take to relearn.

the backstory:
Have been out the evo game since 08 and now recently picked up an 8 for a fair price just however have been dealing with odds and ends. When I got the car home I was going through and found 2 vac lines that were off; line to the egr valve and the vac source line to the factory recirc valve. Plugged these two back in and this is where my high idle issues started. After this the car would idle steadily 1500 fully warm. I did a boost leak test and found that the throttle body seals were leaking badly and wouldn't even hold 6 psi. Replaced them with a set of works high pressure seals, I did not clean the TB when it was off and yes it still has the factory moly coating. When I went to check the BISS it was fully bottomed out so obviously the previous owner was trying to adjust idle screw to drop idle due to vac leaks (when I got car it idled steady at 1k rpms). I adjusted BISS using a snap on modis scanner and locked stepper motor, with motor locked car idled steady at 1k rpm, unlock and car idled up to 1500rpm. I was able to source a known good IACV motor for $20 and put that in so I could rule that out. So here are my questions:

1) After setting BISS how long does it take for the IACV tables to relearn (keep in mind mine had to have been way out of whack),I have put 120 miles on the car since setting BISS?
2) While performing boost leak test factory valve leaks like crazy could this be the cause of my high idle?
performing test with adapter on turbo inlet and pressurizing all piping and IM.

*any suggestion greatly appreciated, really wanted to post the question incase anybody else is having the same issues.

 

Keep searching. High idle is usually vaccum leak.

 

I will check again and isolate the factory valve, just found it odd when iacv is locked that idle is fine and that it's high when it's working

 

From what I read, it takes a few hours of driving in stop and go traffic for computer to learn.

 

Good to know I will keep putting some time on it

 

Also replace o-rings on the biss screw and IAC warm up flapper.

 

So an update:
As of today have put over 2 hours and 180 miles of a mix of city and highway driving, I have noticed that the idle is slightly lower however my idle will not drop lower than 1250.
I performed a boost leak test earlier today and sprayed everything down with soapy water and the only thing that is leaking is the factory 8 diverter valve internally, could this be part of the issue of my idle woes by chance?
My other thought was to disconnect the battery and then reconnect next time I go to drive it (probably in a week or so) but from what I've read disconnecting the battery plays no part on the iacv tables, maybe someone can chime in if I'm incorrect on this?

thanks for the help by the way guys thighs been a pita

 

After the battery is disconnected my car will relearn idle in one trip to the store - 5 mile round trip. Even when in the process about the only trouble it has keeping the car running is when the A/c kicks in. So, yeah, you are probably having to redo whatever the previous owner did to tame the idle.

 

Hmm alright well going to try disconnecting battery again to see if that helps, my only thought was maybe such a drastic change that it can't compensate that much between one reset (somewhat like short and long term fuel trims, big changes out the gate then get more and more minute as you drive). So keeping my fingers crossed that this helps but well see.

 

So got fed up and decided to do another boost leak test...found the wastegate solenoid leaking like crazy and a pinhole in the pressure supply line to it. Question:
Can I run a manual boost controller in place of the factory wastegate actuator solenoid without adjusting it up (keeping it at 0) just to test if this fixes my idle?

 

For idle yes. For boost yes if turned down all the way and raising little by little till you get to target boost.

 

I just want to run stock wastegate pressure is all

 

you can just run a tube directly from the compressor housing to the wastegate actuator for the purposes of your test. You should only ever be able to make wastegate spring pressure which is fine, and you will probably have worse spool.

 

Why don't you just replace the hose instead of adding a MBC and not change the boost setting? I'm confused how you want to run stock boost and want to add a MBC, which is meant to increase boost.

*Unless you meant your factory boost controller is leaking.*

 

Correct the factory wastegate solenoid is leaking. That's why I was asking about using a MBC in place of it.