So i just removed my VFAD after reading all the threads. but...im having trouble now. everytime i put the car in neutral as im driving, the rpms, just keep going down to 0 and then the car stalls!. any ideas of what i might have done wrong?

the only thing i can think of is that i did not plug up the hose, would that do anything?

 

Did you plug the nipple behind the throttle body?

 

no i left part of the hose still on figuring i wouldnt need to plug it. should i jsut remove all of it?

 

You can remove all the hoses, just make sure the intake is capped.

 

okay. im going to try this tomrw hopefully it works..

 

I just capped the hose where it rests in front of the intake box in case I ever revert back to stock... no problems so far. I have seen 5-6 degree hotter temperatures though... will be making a custom cai shortly to get colder air

 

^^Yeah... as long as you cap the line going to the intake and not the line going to the VFAD actuator it'll work just fine too.

 

hmmm... now you got me thinking. when I removed the hose off the "mesh tube" that goes through the bumper, a vaccuum was released, so I figured capping it would be good. Do I actually have to take out all the crap under the intake box up to the uim to remove vfad?

 

and I capped it right after the actuator, yes...

 

You do not need to cap the actuator side of the line.
The VFAD valve needs vacuum to close, so just keeping that line "uncapped" is all you need.

 

Let me try to explain this better:
There are sections of hoses and hard lines in the VFAD assembly.
You also have a solenoid, vacuum chamber, and a one-way valve.
If you disconnect a hose anywhere in this assembly, you'll bleed off vacuum to the VFAD actuator and the valve will open.
The valve will remain open until vacuum is applied to the actuator.
This is why you do not need to cap the hose leading to the actuator, but the other side of the line needs to be capped so you don't introduce a vacuum leak to your intake.

There are many ways to do this instead of capping the nipple behind the throttle body (as I posted above).
Here are a couple examples:

You can remove the hose connecting to the solenoid (on the actuator side) and cap the nipple on the solenoid.


Or you can remove the hose from the vacuum chamber (on the actuator & solenoid side) and just cap the nipple on the vacuum chamber.


These are a couple examples just to visually show what side you need to worry about capping (which is the line leading to the intake).
The goal is to prevent vacuum from reaching the VFAD actuator (which closes the valve) and plugging the line leading to the intake (to prevent a vacuum leak).

But some like to just cap the nipple behind the throttle body and remove the rest of the line to make it look cleaner.

 

Oohhhhh... gotcha. So I need to uncap my capped line then...

Thanks for the excellent illustrations Jon

 

You don't NEED to because you already bled the vacuum out of the actuator.
But capping it (on the actuator side) isn't going to do anything useful since you won't generate vacuum with the hose uncapped.

 

here we go... Im a bit vfad retarded



Edit: nvm just read your above post. Everything makes sense now lol. Thanks again

 

I'm at work and can't view Photobucket pics, only attached pics.

 

Well you helped me figure it out anyway, thanks man

 

VFAD is a one way line, so just cap it anywhere, its same ****.

 

haha its makes sense now. i ended up just capping the nipple behind the throtle body and it works :D

 

i didnt cap mine at all... i left the line in the bumper and put a breather on the end of it... works perfect

 

Glad it worked out for you!
I always suggest capping behind the throttle body since its easy to explain to others.
Capping elsewhere in the VFAD assembly would involve knowing to cap the intake side and not the actuator side (which involves me drawing little illustrations like above ).

 

So if you leave the nipple behind the throttle body, the VFAD will remain open?

 

Yes. The VFAD valve needs vacuum to close.
So if you remove the source of vacuum (intake) the valve can't close.

 

Oh i thought it was closed all the time and needed vacuum to open. I really don't wanna remove all that crap if I don't have to.

 

I made a DIY video explaining how to test the intake valves (VFAD, VDI, SSV, and APV).
You'll see that I used a vacuum pump to close the VFAD valve (the SSV and VDI are opposite and requires vacuum to open their valve).
https://www.rx8club.com/series-i-do-yourself-forum-73/diy-troubleshoot-intake-valves-174009/