Starting Air Valve on 4th gen (sorta long, not too much) - Honda Prelude Forum

thatchmaster · 05-14-2001, 09:23 AM

Ok. I don't know if anyone remember's my crisis before about trying to figure out what the hell to do with this one vacuum hose when I put my type-S intake on, but we came to the conclusion that it was the hose to the starting air valve.

From what I can get out of the helms (pg 11-110 I think), it takes in extra air from the intake pipe when starting the car, and puts it directly into the intake manifold, without going through the throttle body, to ease starting.

Since that hose has been off, I haven't noticed a problem w/ starting (note: the F22 doesn't use this), but my idle will dip down a lot while I'm waiting at a light.

I know some other 4th gen'ers had left this hose off.

Is there something I can do with this hose? There's no spot for it on the type-s intake piece, as the 5th gens use a different design. I've thought about just making a hole for it.

Do 4th gen AEM's and other intakes have a hole for this hose? (I'm still not going to get one, I was just wondering if they had it on there)

I tried plugging the hose, just to see what result I would get, and my idle was fine, but when I tapped the gas (from idle RPM), the RPM's would go up from 700, to about 1500 as normal, but then jump to 2000 and then go back down to 700 again. So it was giving a bunch of extra air in there.

The other thing I noticed with it plugged, was a weird "knocking/clunking" noise. From idle, when I tapped the gas, it would "clack", like something was opening. When the RPM popped up to 2000 (because that hose was plugged) it would "clunk", like something was closing. Maybe better described as a "tick", followed by a "tock". I couldn't place the sound, and didn't have time to further examine exactly where it came from, so I pulled the little cap I made, off of the Starting Air Valve hose.

Now, I remember someone also said not to plug the hose. Fair enough. Just experimenting.

So, what I need, is some other 4th gen guys who've dealt with this thing. I'm sure it's not too many, but if you could help me out, I'd really appreciate it.

Dr. James, I know you had a word in the last post I had about it...

Thanks
-Erik

starscream · 05-14-2001, 10:04 AM

Ill take a pic of the hoses on my AEM a lil later... Im not sure which hose your talking about...

If it really bothers you, then Id suggest making a hole... Its not causing any harm to your car the way it is right now? right?

sohcpower · 05-14-2001, 10:21 AM

Are you talking about the hose that is the smaller of the two that runs along the top of the intake manifold by the firewall?

starscream · 05-14-2001, 10:32 AM

ok... circle it!

(edited: WTF its not posting the pic... I found a bug.)

thatchmaster · 05-14-2001, 11:11 AM

Chris-- Yes.. I think you're talking about the same one here..

On h22's, there's a small (ID of about 1/8") hose that goes into the intake pipe, just before the throttle body. That is the one that pulls air out, bypassing the TB, and aiding startup. I don't really know why my idle dropped because I'm letting the hose dangle and bring in engine air. I know it's not great to grab air that hasn't been filtered, but hey.. I can't think of anything else to do with that darn hose. I might just drill a hole in the type-s pipe and fit that hose in.

Jon -- I'd love to circle the hose and show you.. but, I have no programs I can really use to do it here at work. Heheh.. thanks tho!

Here's a link to the pic that I was showing before. It's a hella huge picture, but, it's the hose with the gold/bronze slash-cut fitting on the end of it.

http://thatchmaster.tripod.com/intake/typesintake5.jpg

You can see the other type-S intake pics in that directory too.. so if you wanna see where the hose goes to...

Thanks guys.

-Erik

ps- Jon, move zig.

ImSLeEpY · 05-14-2001, 09:23 PM

are you talking about the hose that was orignally connected somewhere down under engine space to the resonator? if thats the one yer talking about, no AEM doesn't have that, just the little one that connects to the valve cover. In the installation it just said to plug the hose. but i am also experiencing bad start ups and drooping idles.

starscream · 05-14-2001, 09:30 PM

my idle revs up and down when I have the a/c on...

thatchmaster · 05-14-2001, 09:54 PM

Quote:

Originally posted by ImSLeEpY
are you talking about the hose that was orignally connected somewhere down under engine space to the resonator?

Nope, that's not the one.

It's right in front of your throttle body. You really can't miss it. It runs up behine the intake manifold, and then ends on a metal piece. That piece is the Starting Air Valve. 5th gens don't have this. Or at least not in the same spot...

-Erik

Dr. James · 05-15-2001, 11:41 AM

The one that you are refering to is the one that is capped off in the picture above. Normally there is a hose that extends off of that hard line to a little brass nipple that is plugged into the stock intake pipe on the 4th gen. This little nipple has no place to be plugged on most aftermarket intakes. When I install intakes I use 2 methods for that little nipple. If the intake pipe is metal like on AEM's or DC sports Etc. I drill a small hole and set the nipple into the hole, and use sheetmetal metal set liquid around the edges to permenantly bond the nipple to the pipe. looks good and there is no side effects. if the pipe is plastic, Iceman, then I use esentially the same method, bit instead of metal set I use Epoxy. It works just as well, and you can't even tell. or you can put a small hole in the rubbwe connector, and place the nipple into the rubber, and wedge it between the lip of the intake pipe and the T/B. Both methods work just fine. I personally have the Nipple wedged between the intake and the T/B.

thatchmaster · 05-16-2001, 02:20 AM

I was really hoping you'd come around here James, thank you. That was the piece I was referring to.

What does this valve do while the engine is running anyway? It only "helps" in startup right? Yet there is vacuum while the engine is on. I guess I don't really see the point of this valve. I am going to put it where is goes, however.

-Erik

Dr. James · 05-16-2001, 11:54 AM

I honesetly have no idea why that valve is there. I have never really studied about it too much, But I think that it has to do with emissions. It opens and allows more air to enter the combustion chamber during start up, I guess this is too haelp eliviate the rich burn condition during start up. But I have no idea what it does after start up. I just reconnect the hose, becuase Honda put it there for a reason, and without it the car had a wierd fluctuating idle.

starscream · 05-18-2001, 05:33 PM

You know what, I noticed today that my car also chokes a little when I start it up. I guess I never noticed it until it was pointed out, now. would surging revs at idle w/ a/c on also be a symtom of the starting air valve??

Tola · 05-20-2001, 09:15 AM

My AEM CAI came with a rubber gromet and a plastic valve thingy for that 1/8" hose. It came already drilled. But my dumb@$$ dropped the gromet and plastic valve into my back yard drain!! So I had to run to Pepboys and get a new valve and gromet. I don't know why it's there that hose is there either. My idles seems pretty normal, although sometimes it dips to 500.

not rice · 05-23-2001, 09:35 PM

deceptakon

mine has always done the same thing with the A/C. i dont remember if the sh*tty "surging revs at idle" (nice way of saying that, BTW) were there before i put the AEM on, cuz i put it on like right when i got the car. if there is a way to help the A/C revs and someone knows how to fix it, help us pleeeeeeeeeeease, i dont know about you but i turn it off @ red lights cuz it gets embarrasing

sometimes when the car has been off for awhile, the first few times i push in the clutch to shift, the RPMs bounce up a bit too. hmm...n e 1 else?

glad im not the only one....

later

not rice · 05-25-2001, 06:26 PM