What is this and what does it connect to? (1 Viewer)

[CurtB]

Tracking down vacuum leaks and found that the big hose coming in to the bottom of the red thing was just dangling loose against the exhaust manifold. What should it be connected to?

If I knew what to call it at least, I might be able to find the schematic. What is the red thingy?

 

[2mountainfish]

That is an HAC . (High Altitude Control Valve). I you are referring to the port on the bottom with the cap on it, that is a vent and should be open to the atmosphere. Mine has a long hose on it that runs down the inner fender well towards the firewall.

 

[Output Shaft]

Remove this cap and connect to open hose.

 

[CurtB]

Hah! No, I put the cap on. The hose WAS connected there but other end was just laying against the manifold. Had been there some time because it was hard and cracked. I should've made that clear in the original post...

 

[CurtB]

I just saw 2mountainfish's reply. That makes sense. There was a good bit of vacuum at that location, though...

 

[Dynosoar]

There should be NO vacuum at that location. If there is you have a broken HAC valve.

 

[2mountainfish]

I agree with Output Shaft. I had the same problem with vacuum at that hose, made my engine run really crappy at idle, if it would idle at all. I exercised the valve a bunch of times and it finally shifted inside, no more vacuum. The vacuum diagram shows it vented to the atmosphere. As far as capping it,maybe someone can chime in on weather that is a good idea or not. I live at 4000ft and go up from there , so I need all of my High Altitude systems working correctly.