I bought a used AC system for my 1992 4x4 Pickup and it came with an idle up. Got the AC working fine and I see where the electrical connects on the passenger side, but I do not see where the two vacuum lines connect. Everything else has been plug and play, but I don't see where the vacuum lines will go. Do I have to T into existing lines? Does someone have photo of theirs?

 

I assume you have the vacuum switching valves. There are two larger ports, one on the plenum, and one right below it on piping under the plenum. The VSV itself switches a smaller vacuum line (that Tees into the line to the FPU), which works an actuator (attached to the VSV) that switches the two larger lines.

 

Thanks for the info, but it is a bit confusing. Where is the Idle Up and what is a FPU? I'm new to this. Do you have any photos of where the two vacuum lines go or do I have to fabricate something? Thanks

 

I don't have a photo, but here is a drawing: http://web.archive.org/web/201102052...24vacuumsw.pdf I count 5 vacuum lines, so I don't know what you mean when you talk about "two vacuum lines." You say you have "an idle up," which I assumed was the VSV-actuator assembly. That assembly attaches to the apron on the right side, in a row with the PAIR, FPR (FPU), and EGR VSVs.

My presumption is that the two AC Ports (on the plenum and the tubes below the plenum) are present but capped on your truck. But I don't know what you have.

(FPU is "Fuel Pressure-up," sometimes called Fuel Pressure Control System, to work against vapor-lock. it's labelled FPR in the drawing in my earlier post, as it connects to the fuel pressure regulator.)

 

 

That's the VSV. You don't show(have) the actuator. Take another look at the manual page I cited.

Here's a drawing. They're calling the VSV "Valve, Magnet, for Idle-up Device", and they're calling the actuator "DIAPHRAGM SUB-ASSY, COOLER"