Here's the story-
My A/C works great, still R12, and blows ice cold. It just drops at idle with the A/C on, like to around 500 to 600. I adjusted the A/c idle-up vsv, all the way in and out, but no change in rpm. The connector to the vsv is getting 13.something volts with the A/C on, zero with it off. I changed the vsv with the one from another motor, no change. Any ideas? I did search!

 

Very common for the vacuum fitting that feeds the idle-up VSV to get clogged. Make sure you are getting vacuum to the VSV so that is has something to switch (VSV=Vacuum Switching Valve). Also, quick test of the idle-up valve and vacuum source is to bypass the VSV and connect the vacuum hose direct from the intake to the idle-up valve.

 

thanks 4crawler, i'll definately give your suggestions a try..! if i pull some vacuum from an external source to open the valve, which fitting would be the best? the one that goes to the center of that little UFO looking gizmo?

 

Wherever there is vacuum I suppose.

 

I tried messing with mine, I dunno if what I was turning was even the right thing but it was connected to the ac stuff a red and black cap to turn. tried turning both and it didn't change the idle either..

 

As I mentioned, you need to make sure that the vacuum line feeding the VSV (and ultimately the idle up valve) is clear. If the line is clogged, the VSV and idle up valve get no vacuum. The idle up valve is vacuum operated. No vacuum = no idle up, regardless of where the knob is set to. Here's the one on my 22RE, idle up valve near the "E" on the plenum, white plastic knob on top, VSV in the lower right corner, inlet vacuum line on the bottom, output vacuum line on top. Red caps are where the p/s idle up VSV used to attach.

 

I definately have vacuum at the vsv, just checked it out. I tried the bypass and still did not idle up....., maybe the return is clogged? i'll give that a look see next.

 

I checked all the vacuum lines to and from the vsv and they are clear. The vsv is getting energized, i can hear it click when the the AC is turned on. I also tested it by applying power to it, it's working....uuugh...still won't idle up.

 

Is the idle up valve blocked where it goes into the intake manifold? Did you try removing it to make sure that port is clear? I turned on my AC for the first time since I bought my 4Runner last year. It still blows somewhat cool air but it didn't idle up a lot. But then my 4Runner still has the original coolant from 17 years ago!

 

Yes, I would check the passages in the idle up valve. I think it can be removed from the intake, then shoot some intake cleaner in and make sure it is all clean inside and where it attaches to the intake. I recently picked up a gun cleaning kit and used those small brushes to clean my EGR valve. Would be a similar type of process for the idle up valve.

 

the vsv is operating correctly as per the FSM test procedures, and no clogs, yet still will not idle up...could it be something else?

 

The VSV just supplies vacuum to the idle up valve. If the VSV is working fine then the only other choice is the idle up valve itself. Make sure it is not plugged up inside.

 

4Crawler, thanks for all the suggestions! I had another few minutes to chek it out this morning. There is definately vacuum through the idle up valve with the ac on, none when off, so at this point i'm pretty sure that the vsv and idle up valve are doing what they should, but still won't idle up regardless of how the idle up valve is adjusted.....

 

The idle up valve is actuated by vacuum, but then it needs to have air that is bypassing the throttle body (fed by a larger hose) and it meters that air into the intake. On my 22RE, I can hear the air hissing sound as it goes through the idle up valve. Make sure the inlet hose is open and make sure the connection of the idle-up valve to the intake is not clogged. It may be that the vacuum actuator is plugged up inside. Try some intake cleaner in the valve to wash it out well.

 

well....uhhhhh.....duuhhhh.....stupid me! The line that feeds the idle up valve was plugged,...by me! I had a real nice blue anodized elbow on my truck, that eliminates the two mini air boxes. One of the lines it eliminates was the feed to idle up valve itself. i guess if i can get a bung for a hose in the blue elbow, i could re install it and have things work correctly ( it's worth a try..). At least i took the oppurtunity to clean my throttle body, and k&n. Thanks Yotatech!