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Old 08-30-2012, 04:43 PM   #1
 
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Default TBI Vacuum Hoses
Hey guys,
I'm hooking up my vacuum lines on my TBI swap, and had a few questions. Figured since a few of you are TBI, you could probably help out.

The first question I have is on the back of the intake manifold. There is a small silver Hex screwed into the manifold with a vacuum port and hose attached. What does the other end of that hose attach to?

The other is cruise control related. In the cruise control harness, there is a large vacuum hose. Where does that attach to on the engine side? The interior side connects to the brake switch. I thought it connected to the cruise control servo, but it seems too large in diameter.

The next one is on the MAP sensor. I have a vacuum line from the TB to the map sensor, but on the MAP sensor, there is port, but nothing hooked up to it. Should there be something hooked up there or is it open?

The vacuum ball...where does its vacuum line attach?

Last, but not least, the climate control harness coming out by the heater box has a vacuum hose, where does it attach to?

I really wish I had taken more pictures when I tore down my 87, dangit! I looked through my factory manual, but couldn't find anything really.

Thanks!

Last edited by foamypirate; 08-30-2012 at 04:51 PM.
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Old 08-30-2012, 04:48 PM   #2
 
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There's two ports on the cruise servo, the larger one is for the large line and the smaller one is of course for the smaller hose getting engine vacuum.


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Old 08-30-2012, 04:49 PM   #3
 
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Originally Posted by RetroC10Sport View Post
There's two ports on the cruise servo, the larger one is for the large line and the smaller one is of course for the smaller hose getting engine vacuum.
Cool, thanks! It just seemed loose on there, so I wasn't sure.
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Old 08-30-2012, 05:16 PM   #4
 
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Originally Posted by foamypirate View Post
Hey guys,
I'm hooking up my vacuum lines on my TBI swap, and had a few questions. Figured since a few of you are TBI, you could probably help out.

The first question I have is on the back of the intake manifold. There is a small silver Hex screwed into the manifold with a vacuum port and hose attached. What does the other end of that hose attach to?

The other is cruise control related. In the cruise control harness, there is a large vacuum hose. Where does that attach to on the engine side? The interior side connects to the brake switch. I thought it connected to the cruise control servo, but it seems too large in diameter.
I think the vacuum ball is T'ed in with the cruise control servo....or is it the HVAC? Lemme look.
The next one is on the MAP sensor. I have a vacuum line from the TB to the map sensor, but on the MAP sensor, there is port, but nothing hooked up to it. Should there be something hooked up there or is it open?

The vacuum ball...where does its vacuum line attach?

Last, but not least, the climate control harness coming out by the heater box has a vacuum hose, where does it attach to?

I really wish I had taken more pictures when I tore down my 87, dangit! I looked through my factory manual, but couldn't find anything really.

Thanks!
The HVAC hose goes to manifold vacuum, I T it in on my brake booster line.
The MAP line comes from the back of the TB, the egr lin is from the passenger side port on the TB, PCV is the large port in the middle,EVAP is the medium port below the EGR.
There should only be one vac port on your MAP.

Last edited by Jims86; 08-30-2012 at 05:22 PM.
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Old 08-30-2012, 05:23 PM   #5
 
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Yup, its teed into the climate control line.
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Old 08-30-2012, 05:24 PM   #6
 
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My manifold rear fitting has a hose coming out, then a check valve, then a T splitting off to the ac/heater and CC/vacuum ball.

MAP sensor should have one line. Are you sure you are not referring to the EGR control valve? That has a vent port and 2 vacuum lines.


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Old 08-30-2012, 05:26 PM   #7
 
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And my brake vacuum line feeds off the front/right of the throttle body.


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Old 08-30-2012, 05:53 PM   #8
 
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Originally Posted by Jims86 View Post
Yup, its teed into the climate control line.
Originally Posted by 89Suburban View Post
My manifold rear fitting has a hose coming out, then a check valve, then a T splitting off to the ac/heater and CC/vacuum ball.

MAP sensor should have one line. Are you sure you are not referring to the EGR control valve? That has a vent port and 2 vacuum lines.
Thanks guys! That's exactly what I needed.

89S, you are right, it was the EGR control valve. I was working from memory, and for some reason thought it was MAP.
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Old 08-30-2012, 06:12 PM   #9
 
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That would be funny as shit....hook up the map sensor wrong, start it, and he comes back posting that his 84 is rolling coal.
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Old 08-30-2012, 06:15 PM   #10
 
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Originally Posted by foamypirate View Post
Thanks guys! That's exactly what I needed.

89S, you are right, it was the EGR control valve. I was working from memory, and for some reason thought it was MAP.
Jims86 taught me.


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