Shagool22

I finally decided to get my AC going before summer. Installed new (used) AC compressor because the clutch on mine was bad. Recharged it and it blows nice and could as it should!!

But when I turn the AC on, my idle drops 100-150 rpms. I know it's supposed to idle up via AC idle up/vsv. Tested vsv and even tried a different one I had from my parts truck with no change. Still the multimeter on it and they both checked out good.

The knob on my fast power steering/AC idle up valve (not sure what its called) is screwed all the way in. Because when I turn the knob it changes my idle up or down as if I was turning the idle adjustment screw.. If I unscrew the knob to half way, then I have to completely tighten my idle adjustment screw to get my idle to 750. I'm out of ideas!! I know something isn't correct here.
From my understanding the knob on the ps/AC idle up valve should not affect my overall idle. Should only affect idle with AC on or when turning very sharp. Am I correct?

I'm stumped. If anyone has any pics of their 87 4Runner I would like to verify my vacuum lines are routed correctly in that area

grumpin

Have you tried a new o ring on the idle screw? Maybe if that is sealed, if it needs it, then you could run the idle up valve out and adjust your rpm for idle and then the idle up valve for the A/C.

millball

On my '87 'Runner, the AC idle-up and the power steering idle-up are two different systems.

The steering one is vacuum actuated, while the AC one is electrically controlled.

I believe there is an adjustment for the ac idle-up system on the evaporator box, under the dash, behind the glove box.

The FSM will tell all.

grumpin

I'm sure they both use the idle up valve. Nothing in the FSM about either the idle up valve or an adjustment near the evaporator box. I have adjusted my A/C idle using the idle up valve. The A/C system uses a vacuum switching valve.

Shagool22

Grumpin are you talking o ring on idle adjustment screw or idle up valve knob? My idle adjustment screw works as it should (doesn't mean it's not leaking) just making sure were on the same page

The first thing I want to correct is why the idle up valve knob changes my idle speed when I turn it. I know that can't be correct. I don't think its faulty, I swapped the one out of my parts truck with no change. Does not make sense

scope103

Are you talking about this valve ("actuator"): http://personal.utulsa.edu/~nathan-b...24vacuumsw.pdf ?

If you have vacuum through the VSV to the actuator, the actuator is open and adjusting the screw should change the amount of idle-up. If the AC is off and this is happening, disconnect the small vacuum line (VSV - Actuator) to a) see if there is vacuum on that line -- there shouldn't be, and b) whether that stops the action of the screw on the actuator.

Then just work backwards. If you have vacuum on the VSV-Actuator line w/AC off, check for voltage on the VSV. If there is none (well, less than 2v or so), then the VSV is stuck open. If there is 12v or so, then the amplifier is sending an idle-up signal with the AC off.

Shagool22

Scope103 I don't think you understand what I'm saying when I adjust the screw on the actuator. It doesn't change the "amount of idle up" it literally completely changes my idle as if I were turning the idle adjustment screw. Already checked vsv. It's good. Plus as I mentioned I even swapped in another.

Shagool22

Here is a video of the issue I'm having.

https://m.youtube.com/watch?v=0-sp55...ature=youtu.be

Shagool22

Problem solved. Had the 2 vacuum lines between VSV and actuator crossed. Finally works as it should!! Thanks for the input guys.

grumpin

Good! What scope was saying is if that vsv is open or the amplifier commanded it open, you would be adjusting your idle with the idle up valve, as it did. In the manual scope referenced, it at least kind of shows you the idle up valve, and some lines. The 87 and 88 manuals just show you how to test the vsv.

Shagool22

I see thanks for clarifying. So I figured out it was working backwards when I had those lines crossed. With AC off it would adjust idle like in video, then I'd turn AC on and I could no longer adjust idle at actuator. Now turning the knob on actuator does absolutely nothing until I turn AC on. All makes sense now lol

luvmyyota2

hello all, new to the forum ,but not to Toyota. I think someone will have this answer pretty fast. as you all know the diagrams on vacuum for the 89-94 22re can be very vague. I recently went to a junk yard "treasure hunt". I stripped the entire ac system from the same year vehicle. 91 base 2wd 22re. i had no factory ac, power steering, or power anything. got the ac in. it works great. the vsv was missing from the donor vehicle. I bought a new one. removed the dashpot and added the idle up diaphragm. question is since the donor had the part and vac tubes missing where does vacuum signal come from or switch to. i referenced the manual and it does not indicate the vacuum source or point of return. i did see a short tube sticking out of intake right near the idle up diaphragm. Any help with pics would be greatly appreciated.

maco35

I hope this helps.

maco35

This is what my engine bay looks like, i hope it helps.

maco35

https://www.yotatech.com/forums/f116...p-help-304870/


https://www.yotatech.com/forums/f116...-valve-308747/

More reading material.

luvmyyota2

thanks maco35, it is hooked up and working. now the next issue. maybe related now, but was happening before ac upgrade. engine is surging like it cant find the right idle point. this happened before ac was installed. still happens when ac is off.

Shagool22

Thats happened to me before. One time it was EGR stuck. I tapped it with a ratchet and it freed itself and started idling normal.
also air in coolant is a popular cause of idle surging, may need a good burp. As well as vacuum leaks. A lot of things that can cause it. Process of elimination lol