Where Does This Hose Go?

wrxnofx · wrxnofx's Garage

I was poking around my engine compartment last night, and noticed this hose is not connected to anything. Where should it go?

It's on the passenger side. I have to think it's a vacuum hose. I tried tracing the other end, and I think it goes into the intake elbow just after the MAF.

86 911 Targa · 08-07-2013, 08:59 AM

Quote:

Originally Posted by wrxnofx

I was poking around my engine compartment last night, and noticed this hose is not connected to anything. Where should it go?

It's on the passenger side. I have to think it's a vacuum hose. I tried tracing the other end, and I think it goes into the intake elbow just after the MAF.

Smoove1010 · Smoove1010's Garage

Does this help? I think your hose is item #30.

wrxnofx · wrxnofx's Garage

Aha, yes. I was looking at that same page of the PET, too, Smoove, and had come to the same conclusion.

I was confused, however, as it appeared that the only "mounting" location was on top of the valve, not to the side, as the PET implied. The pics from 86 are worth 1000 words. THANKS!

One other question - my valve is not mounted to its bracket. The valve has a circular boss on the bottom that obviously fits into the corresponding hole in the bracket. But what holds it on underneath?

Smoove1010 · Smoove1010's Garage

My bracket is like yours - there was no clamp (like the PET pic) to hold it firmly in place, the round "boss" on the bottom of the valve sits neatly in the hole in that bracket, and gravity holds it in place along with a little torsion from the hoses connected to it.

I'm pretty sure that the valve needs to be up at that height though. When I got my car, the valve was off the bracket and just hanging by the connecting hoses. It's in the right place now.

wrxnofx · wrxnofx's Garage

Thanks, Smoove.

The hose is re-attached. My bracket was loose, also, so I moved it to the proper orientation for the valve to sit on and tightened it back up.

Can I expect any noticeable change in anything now that it's properly re-attached? Presumably the hose pulls a vacuum, which would lift the diaphragm in the valve. However, one of the other hoses that leads from the valve also enters the intake just slightly further upstream, so it would pull a vacuum, also. Now I would expect the vacuum on both sides of the diaphragm to be similar, compared to before it was attached.

JAR0023 · JAR0023's Garage

No real difference until it gets cold then you might get to hear the buzzing from the valve. Back of the throttle body, the piece with two vacuum lines is a thermotime switch. It opens under a certain temperature, that I can't remember now. Once it opens it pulls a vacuum on the valve mounted above the oil filler. This allows warm air to be pulled from the oil filler neck through the valve into the airbox. The idea here is that this will prevent freezing in the throttle body at cold temps by pulling warm air from the oil tank.

As the diaphragm in the Aux Air Valve ages it loses it's pliability and instead of sealing you get a kazoo like buzzing noise. My car came out of SoCal so I'm not sure how long it had been since it was cold enough for the AAV to kick on. I would get the buzzing on sub 40* mornings last winter. By the time I figured out what it was the buzzing stopped. Fingers crossed the warm oily air from the oil tank got my valve to seal. If not I'll mess with it this winter. -J

wrxnofx · wrxnofx's Garage

Thanks for the info, J. Considering I live in Minnesota, chances are I may just hear the buzz this fall. Incidentally, I looked up the valve on our host and it seems the valve is NLA.

Skip1 · Skip1's Garage

For what it's worth, there are two types of air valves. The one that wrxnofx posted is the old type with the vacuum line on the top, and the support bracket that fits directly underneath the valve. Mine actually had a metal spring washer which pressed directly onto the base of the valve once it protruded through the bracket - far from secure IMHO (kept falling off). The new valve has the vacuum line on the side, and comes with a new style bracket as shown in Smoove's diagram. The only challenge I had to date in upgrading the system, was a variance in diameters of hoses leading from the side of the valve (not the vacuum line, but the main larger diameter hose (#28 in the diagram), didn't fit / NLA. Just my 2 cents.