Cool, thanks guys. I feel like such a noobie after driving "brand new" trucks for a few years......I haven't actually had to work on anything except to bolt on goodies. Most all of my limited knowledge has come from my own interest in autos and from the web. Most of my friends stop at bolt ons, so this kind of help really does help.

Ok, I will NEVER run a/c again, so I don't need to bother with the a/c idle screw. The VSV (what is this) is used to regulate fuel pressure, correct? But, I could hook up the FPR directly to the intake and bypass the VSV? I searched and found where Roger had posted about doing this. I guess I gotta break open the service book again and figure out what and where the VSV is and see if I want to fool with it.

Darin, if I end up with this as an extra part I don't need, I'll let you know. Though, since I have a complete 86 for parts....I probably have just about every part you may need. PM me if you need something. Once I get the 85 done, I'll strip the 86 and part it out, but I may be able to help you along the way. Both of my 4Runners are SR5s.

Close, but not quite... There are 2 separate VSV's (Vaccum Switching Valves). 1 Controls fuel pressure, the other controls the "idle up" for the PS and AC. You could bypass the one for the fuel pressure, but you may want to leave the other intact, as you might find yourself stalling under PS loads on the trail.

That makes much more sense now, thanks <img src="/forums/images/graemlins/cheers.gif" alt="" />. Next Q, does the a/c idle screw have anything to do with the PS?

VSV = Vacuum Switching Valve (electrically operated), basically a vacuum relay, so to speak. Here's a picture of the A/C VSV and idle up valve:



Here's the one for the FPR:

The idle up vavle can br operated by either the p/s pressure switch or by the A/C VSV. Does the same thing, boosts idle speed to keep from bogging down the engine at idle when A/C or steering boost is needed.

Very nice pics, thanks Roger. Good idea about labeling the parts.......I'm gonna do that. Good way to learn what's what and not have to flip open the book each time.


So, that plastic screw does control the idle boost speed for the PS? I'm a little slow on the vacuum/electronics stuff.

"my oil pressure is LOWISH" LMFAO!!!! <img src="/forums/images/graemlins/notooth.gif" alt="" />

Reminds of of these two fat nasty buttcrack rednecks I saw pull into a gas station in North Carolina one time in a '77 Trans Am...complete with wore out door hinges and tires with wire hanging out...they went inside and bout NINE PINTS of STP and poured it ALL in the weezing 400 that was in that car. <img src="/forums/images/graemlins/notooth.gif" alt="" />

Both the A/C and the P/S vacuum lines connect to the same idle up valve. Its a diaphram that is pulled open by the vacuum present on either line and it opens a valve that passes air into the intake plenum (via the larger "vacuum" hose), the amount of which is controlled by the plastic knob.

Thanks Roger <img src="/forums/images/graemlins/kewl.gif" alt="" />