Some quick vacuum hose help?

[Nutro]

I'm unscrewing everything the previous owner screwed on this 88 K5 I just bought. They removed all of the smog stuff and removed the cruise control under the hood. None of the A/C or heater stuff was working. I found the blower motor resistor was dead. Installed a new one and I have air movement now. Under the hood, The vaccum ball has 2-3 feet of rubber hose and into a Tee. That's it. As I understand it, the ball only holds vacuum for the cruise setup.

Out of the firewall, the little brittle 1/8" vacuum hard line was taped off. I removed the tape and need to figure out where I can get vacuum so that the Vent/Defrost etc works. As it is now, I can get air movement but the blend door isn't switching functions.

I also noticed on the rear of the intake behind the Throttle Body there is a Tee or vacuum fitting. It looks like someone plugged it off. Can I just run that main 1/8 hard line to that manifold vaccum?

With them removing the smog/emissions/cruise control stuff, I am LOST on what should go where etc

 

[diesel4me]

Type in "1988 GM truck vacuum line diagram" and then click on "Images",you'll find lots of factory hose diagram "maps" there..

 

[Nutro]

I've googled til my eyes hurt haha. I need to know what is proper for having the EGR/Cruise and related emissions stuff removed, if anyone knows.

 

[dyeager535]

Dumb question (dumb PO's) is the core support sticker gone, that shows all this stuff?

I can't recall if cruise is on that or not, but someone should be able to take a pic of theirs and post it for you I would think.

The vacuum reservoir is to ensure vacuum remains steady as the throttle is manipulated. I want to say both cruise and the AC/heat vacuum source were connected to it. Also a check valve in the hose to the vac. reservoir from engine.

 

[Wes Harden]

the vacuum ball is connected to manifold vacuum. Normally behind carb/tbi to intake. You need the the vacuum ball to maintain vacuum at wide open throttle. If you do not have a vacuum reserve the hvac venting will revert to neutral position, defrost and floor, when you are hard into the gas .

 

[Nutro]

Dumb question (dumb PO's) is the core support sticker gone, that shows all this stuff?

I can't recall if cruise is on that or not, but someone should be able to take a pic of theirs and post it for you I would think.

The vacuum reservoir is to ensure vacuum remains steady as the throttle is manipulated. I want to say both cruise and the AC/heat vacuum source were connected to it. Also a check valve in the hose to the vac. reservoir from engine.

There is a diagram but it is basic and doesn't show the cruise and much detail at all. Hmm so I need a check valve and a couple Tee's

 

[Wes Harden]

That is all emission, required label by federal law. Cruise control needs a brake pedal switch, a vacuum diagram to control the the throttle. Some kind of speed sensor, was a change in 88 for the the trucks, idk which the K5 used. the other components depend which style was used.

 

[Nutro]

So If I am understand this correctly, I need a 3 way valve and plug the end going to the "Servo" into the 1/8" HVAC plastic line from firewall? According to this pic, it goes:

Line out of ball into the top port of 3 way, then out of bottom to engine vacuum and then straight to HVAC firewall line?

 

[dyeager535]

Yes, there will be a vacuum line to a switch above the brake pedal. Hopefully all they did was remove the hoses and left the cruise box and wiring alone under the dash. There is a diaphragm that's integral to cruise operation, there is a wiring plug that runs to it, a vacuum line, and a cable that connects it to the shaft at the throttle body where the cable from the gas pedal connects.

I really dont recall how the heat/ac was plumbed. But I vaguely recall reading that the divert valves will "flutter" if not connected to the vacuum reservoir.