Couple of questions about the 1.8 8v

[20v GTI Guy]

There is a nipple on the back side of the head, a vacuum feed of some sort. What is the purpose of it?

Also, is the ISV needed on this car? mine doesn't seem to be working regardless. When I unplug it and replug it, nothing changes.

Long story short, I'm having an idle issue, and I'm fairly certain it's vacuum related and would love to get rid of as many vacuum sources as possible.

Thanks in advance for the help.

[etta gli]

There is a nipple on the back side of the head, a vacuum feed of some sort. What is the purpose of it?

warm air circulator? Connects to the bottom right corner of the airbox. Completely unnecessary. Replace manifold gaskets and the injector rings if they haven't been done in the last couple of years. Cheap parts and may fix your problem.

[20v GTI Guy]

So I can cap that nipple off, perfect.

As for the injector rings, I actually got some and didn't use them when I rebuilt the head and bought a gasket kit, so I'll pop those out and put them in. thanks.

[20v GTI Guy]

wait actually I think you're talking about the valve cover nipple that points towards the rear. I will remove that if I can, but I'm actually talking about a smaller nipple that I think is down between cylinder 3 and 4.

[ShaggyGTI]

that's the air shroud for the injectors

[20v GTI Guy]

Does that have to keep a vacuum source?

[rabbitnothopper]

Does that have to keep a vacuum source?

if you have air shrouded injectors you must keep the vacuum ports for them in working order