I've been reading up on disabling the Variable Fresh Air Duct valve, mostly to troubleshoot a noise issue (metallic/airy tinging sound).

I found some pictures on the forum of where to remove the line and cap the nipple, but they don't don't quite look like what I found in my car. Is this the line that I should pull off and cap the nipple here?



If so, following that line goes to the below photo... so wouldn't it be easier to pull the hose off that elbow (see below) and cap it there?

 

I capped mine on the intake, like you show in pic #1.

 

I think you have the right idea. Here's the line routing drawing...

 

Yeah, that's it.
Run up to an autozone and just get some caps, but sadly, I don't think the VFAD is your issue.
Here's maybe a better pic for ya.

 

Not trying to thread jack so could someone pm me explaining why you would want to cap the VFAD? I mean besides the possible solution to his noise problem, is there something else?

 

All it does is make more noise and possibly give more airflow(needed or not). As far as I understand it when its working it doesn't let in as much air at lower RPMs and then fully opens up when you go higher. It reduces engine noise by a little bit but nothing really substantial. I'm considering uncapping mine and putting it back to the way it was actually.

 

For those of us with cold air intakes such as Revi intake with the ram air duct, the VFAD is basically meaningless.

 

VFAD is designed for maximum air velocity & volume.

I've been thru 3 different "intakes" including the "OMG PPL SAID SO 1337" aka Mazdaspeed/AEM. It's louder that's about it. So I switch it back to stock and sold it.

If you have stock intake, which is probably one of the "best" out there, you should leave it as is. it has a slight metallic "ding ding ding" sound when it's opening. but nothing major I don't even pay attention to it. so it's fine with me.

 

Would temporarily placing some sort of clamp on the hose to squeeze it flat accomplish the same thing? Meaning, have the VFAD stay open all the time?

Would that put a strain on anything?

I tried wiggling the hose off at the throttle body, and at that white elbow... and I can't budge it, and don't want to risk breaking something. Remember, I don't plan to leave it this way, I'm just curious if I'm hearing the shutter chattering, so I want it stuck open for a drive to see if the (faint) noise stops.

 

Hey...I just noticed.........who added that catch can to this drawing!

 

Catch can and some labels....

 

Yes, very nice indeed!
I shall replace the old one I had saved!

 

So what happens if I unplug the electrical connector going into the VFAD solenoid thing (leaving everything else intact)?

Does the VFAD then stay open... or closed?

I'm trying to find a way to temporarily disable it from closing to see if it's the cause of a minor noise annoyance I hear. I tried pulling a hose off at that white elbow connector (between the vacc chamber and one-way thing), but it will NOT budge.

I know everyone pulls the hose off at the throttle body, but I'm afraid I'll never get it back on again as it's kinda hard to get at, plus I read where someone actually snapped off the nipple there when pulling off the hose. That would really ruin my day

 

Why does it matter what position it stays?

Open or closed as long as it doesn't move you can isolate your 'sound'.

Just disconnect the solenoid.

 

Well, because from what I read, it takes a vaccuum to hold it closed. So I've been wondering if it's not being held closed tightly enough, and so "rattles" at lower rpms.

I'm guessing disconnecting the connector will just leave the valve wherever it is at the moment.

But OK, I'll try it and see what happens, lol... maybe I'll learn something...

 

OK, so I disconnected the electrical connector to the VFAD and went for a nice run.

Made absolutely no difference in power. The engine still sang through 5,000 to the redline as always.

So does that mean disconnecting the wiring harness leaves the valve open? Shouldn't we feel a loss in power at higher rpms if the valve was stuck closed?

 

Search marbles in a can or something like that. I'm to hungover to remember what causes it but its not the vfad.

 

Yup, I've seen a few MIAC videos people have posted, and it doesn't seem to be that. My little sound is faint (too faint to record even), seems from the left/front engine bay area, and at low rpms when under load. The MIAC seems to be pretty loud, from behind the glovebox, and at high rpms.

Mine sounds a lot like the "pinging" in an old car, but I only use 91+ gas.

Noise still there, incidentally, after disconnecting the VFAD electrical connector.

IF that does keep the VFAD open though, it's an awful lot easier to do than trying to pull that silly hose off the throttle body...

 

Have any of you ever disconnected the electrical connection to your (otherwise stock and working) VFAD?

If so, could you tell any difference? Increased noise at low rpms, or loss of power at higher rpms?

I'm just wondering if mine is broken (and just flapping loosely, making the "pinging" noise along with intake whoosh noise), since I can't tell any difference when the connector is plugged in or disconnected.

I see it's a pain to get to, removing the bumper and all... so it's beyond what I can do myself. But I don't want to spend a fortune for a mechanic to check it out unless it's a pretty sure bet something's wrong with it...

 

Yes

No real difference... maybe slight noise increase at low RPM.

With no vacuum applied to the actuator, the valve will stay open.
There is a return spring in the actuator that will hold it open.
Only way the valve could be "flapping loose" would be if the return spring was bad or the connecting arm broke (which I wouldn't put money on either).

1) The bumper is really easy to take off.
2) Why are you so focused on the VFAD valve anyway?

 

Well, just because my "tinging" noise seems to be coming from the driver's side front of the engine area, right where that valve is. Hard to tell though, as it only makes the sound when driving, so I can't exactly put an ear to it

And it's likely not engine "pinging," as I've tried different gas stations, all 91 or 93 octane. It's also my second engine (did it with the original too) with a new SSV and new coils/plugs/wires.

The tinging sound is mixed with a whoooshing intake sound.

The low rpm intake noise is the same with the VFAD connected (electical connection) or not.

It all just makes me suspicious of that valve.

 

I'll have to check when I get home, but I believe you can touch the valve from the "back side".
If you can, then all you'll need to do is remove the air box and reach into front air duct.
I'll play with my spare VFAD assembly when I get off work and see if my hands can reach it that way...