Good to know! Do you know how this device affects idle and is it controlled in the rom?

 

Bump for same question

 

As I recall it is heat sensitive and the heat comes from coolant.

 

Holy thread revival!

My idle air bleed flapper seems to have a air leak. Is this normal? Its holding 25 psi but you can hear the air escaping when you do a boost leak test. I dont know if this piece is supposed to function like that or if i need to pull the TB.

I have the VIII style unit.

 

Hello Camrymatic,
I had the same problem, when I performed a boost leak test. Found the o-ring that is supposed to seal the "bleed flapper valve" was dry and worn. Replaced it and boost leak was gone.

Good luck,
J

 

Thanks!
I didnt realize this thing had another seal. The TB has all sorts of seals apparently.

Is this seal included in the kit Mil Spec. sells? I know there are two small rubber seals and one larger seal with a copper ring around it.

 

Sorry for the thread revival, but is it necessary to remove the idle air bleed flapper if you put a 03/04 TB on a 06 or can you just do a direct swap? Any advantages to removing the idle air bleed flapper?

 

Did you ever get an answer from anyone on this? I'm curious as to what that flapper does.

 

That flapper does very little.

maybe when brand new, it did something..... but still very little.

Proof of this matter, is that midway thru 04, mitsu started implementing the "top hat" designed plunger on the iac vs the 03/04-early. The top hat version sealed the area to where the iac functions / limits the air passing thru the port hole used for idle airflow control. yeah, there is a biss screw, but the iac does most of the control within a limited range.

so 05/06 mitsu eliminated the flapper design for numerous reasons, cost, less pieces to make, etc. + the use of the top-hat designed iac = better idle speed control.

whether you leave that flapper in there or not, does very little. just be sure to replace the o-ring on the 03/04 flapper valve cover. that fkr gets hard & doesnt really seal.

 

Apparently the purpose of the flapper is to provide a temperature controlled amount of air through the IAC circuit? But it provides very little compensation even when new?

 

yep. at least in my experience.

so when i first started doing 65mm tb's, it was with 03/04 bodies. I found that i had to reduce the blade to body clearance to get a reasonable idle speed without having to close the biss screw entirely.

during this time, lets saying minimum idle speed was 1400 rpm due to a big air gap between the blade & body. i mess with the flapper position, nada. modified the flapper so it could close even more, as it's limited to a flat on a portion of the flapper. nada. I installed an 05/06 style iac, whamo - 900 rpm idle speed. the iac made the biggeest change due to it's sealing ability / design.

so during my time messing with the flapper position, i felt it did very little. granted i did all this back in '05.... my memory has faded on the exact details, so please forgive me if i cant recall with 100% accuracy.

 

interesting stuff, I yanked the flapper out of my 03 TB and I have been chasing some IAC related issues around in software. I thought my IAC might be going bad (160k miles so it could be), but I might have shot myself in the foot by just pulling it out.

 

There are definitely differences in the idle control routines between '03/04 ROM and Evo 9 ROM, so the older ROM might be programmed to assume that the flapper exists.

 

That's really helpful information, thanks for sharing. I guess it's going back in. I'll update if anything changes.

 

hi just wondering if someone could give me a breakdown of the TB like what everything is my evo 9 stalls when the AC is on and driving also it idle rough when parked and car has warmed up trying to see if the TB isnt latting in enough to keep everything going smoothly