Where does ISCV line get connected? (1 Viewer)

[CharlieS]

I have the intake and upper plenum off my '94. I'm selectively pruning some systems.

I've found one system that seems good to hold onto, around idle air control.

I need help understanding where the tube/nipple off the bottom of the upper plenum should connect to.

I think I get what it does after some reading.

Faulty 1FZ-FE Idle Speed Control Valve / IAC

Hi everyone, This is an extension of my post for baselining our FZJ80: Baselining our first 80 series: A '93 '3x locked FZJ80 - https://forum.ih8mud.com/threads/baselining-our-first-80-series-a-93-3x-locked-fzj80.1301624/page-4 I was hoping to get more eyes on it. I've been suffering from a...

forum.ih8mud.com

So the next section is probably jumbled, I'll try to fix it when I get to a computer (I am on a phone now).

As I observe it, intake air must hit the hole inside the intake casting, and depending upon how open the iscv is, allows an amount of intake air to bypass the throttle body, go through the intake casting, into the plenum casting and out the side through a nipple to who knows where... the diagram above shows it going into the air intake chamber, but I don't see how that happens.

Where the air must flow and the nipple exits the plenum:

Coming through this hole in the intake casting:

From here where the amount the iscv is open allows some amount of air through.

The ISCV (p/n 22270-66010), which the interwebs tell me is also called the idle air control valve.

The big hole on the inside of the intake where I think the air enters this route:

 

[ppc]

As I observe it, intake air must hit the hole inside the intake casting, and depending upon how open the iscv is, allows an amount of intake air to bypass the throttle body, go through the intake casting, into the plenum casting and out the side through a nipple to who knows where... the diagram above shows it going into the air intake chamber, but I don't see how that happens.

The pathway for the IAC is all internal to the throttle body. There are no nipples or external hose connections for idle control. The nipples in the photo are for running coolant through the throttle body to preheat the air and preventing icing in cold weather.

 

[CharlieS]

Okay, that helps, thank you.

When I look more closely inside the large opening I see the path that the iscv uses. Thanks.

Deep in, back left of squarish hole at 7:00 in pic below.

On my throttle body, that opening just above it, like at 10:00 in the photo above has airflow into it, if I use a hose to blow into it. This is the path that I am wondering about. If I backtrack it, that hole goes to the upper plenum and out a nipple in the side.

When I blow into the round hole on the gasket surface that I'm referencing (appx. 10:00), air comes through the larger squarish hole (appx. 7:00). This suggests to me that it functions as either an air or vacuum passage impacting bypass air flow to adjust idle speed.

The coolant passage seems to be these two fittings on the bottom, 2:00 and 7:00 in the photo below. I removed my caps and verified that there is a free flow from end to end (blow into the hose), and when I cap the ofher end, no air passes.

So I now better understand the internal path of the iscv - thank you for that!

I'm still left wondering what to do with the nipple on the plenum that "feeds" the icsv.

 

[ppc]

There is also a connection for the PCV. All of this can be found in the FSM I suggest you spend some time studying it.

 

[CharlieS]

I have studied the fsm extensively, searched a ton and have been looking at the parts in hand to try to figure it out. Unfortunately, this remains a mystery.

 

[CharlieS]

Air also comes through here fwiw.

 

[CharlieS]

Did a screen shot of a youtube video. Looks like it may be attached to a vsv.

 

[CharlieS]

I suspect it is this line, shown connected to nothing on the left: