87 FJ60 - A/C vacuum actuator

[HopLite]

When I turn on the A/C: The vacuum pot (circled red) does it's job in pulling a vacuum and increasing engine idle.

When I turn off the A/C: The vacuum pot does not release the vacuum and thus the engine idle remains high even though the A/C compressor is off. To work around this, I hardly use the A/C. When I do, I have to pop the hood and manually remove the vacuum hose (grey hose above) from the vacuum pot...the vacuum is released, the engine returns to idle, I re-install the hose and all is well.

Question 1: I vaguely remember something about scavenging a compatable a/c vacuum pot from a late model corolla. Is that correct? If so, what year range? I have searched unsuccessfully.

Question 2: Because the vacuum pot is holding vacuum, I assume the diaphram is good. Is there something else in the system that is not allowing this vacuum pot to release it's vacuum?

Any help is much appreciated. In a few days I will be road tripping the FJ60 to NW Wyoming. Worst case, we drive with nature's air conditioning :]

 

[Elbert]

I would continue to use the A/C as the high idle function is not going to cause any issues. Until you can figure out what is causing the truck not to resume normal idel speed.

 

[Spike Strip]

It's probably the valve (idle up solenoid) that controls the vacuum to the idle up actuator. Valve should be normally closed, but open when you apply 12V. Diaphragm on bottom of Idle up solenoid will release vac when no power to it.

It's the thing the two hoses go to.

 

[TonyGoni]

Old thread...I know, but I just wanted to say thank you! This was certainly the information I needed to solve my issue.

Just got truck back after an AC revival trip to the mechanic (has not worked since purchase). When engaging fresh new AC, idle would go crazy high and stay there. Why high? Carb was rebuilt when AC was totally disconnected/out of commission, so screw was very tightened down.

But why sticking? After following Spike Strip's guidance to the solenoid, I pulled off the bottom cap and there was a strong vacuum sucking IN to it. This didn't feel right, so I checked the diagram posted by HopLite, and the two vacuum hoses were switched on the solenoid. Quick swap and we're back in business.

 

[Gretsch]

Man nice. A suggestion from @Spike Strip from 2011 helps someone in 2022. Took awhile but finally did the trick. Good stuff.

 

[Spike Strip]

The internet is forever!

 

[LETSROLLEM]

Hey Mud’ers,

I’m sorting through some AC stuff as well and had a quick ? I have an ‘84 desmogged and a newish city racer carb and all the stock AC components. I was just curious as to where I connect the vacuum hose from the “valve” to the vacuum “pot” on the carb as pictured circled in red, because the city racer carb does not have the connection port for a vacuum hose also circled in red. Thanks!!

 

[2mbb]

The vacuum actuator circled in red (above) is the secondary advance. Where the linkage attaches to the throttle shaft, that is the secondary throttle shaft.

The AC idle up vacuum actuator attached to the primary throttle shaft. This is the throttle shaft to the left with nothing attached to it. You would need to use the AC Idle up vacuum actuator from your old carburetor or source a used one from some place (www.sor.com seems to have them for $160 (!))

 

[LETSROLLEM]

The vacuum actuator circled in red (above) is the secondary advance. Where the linkage attaches to the throttle shaft, that is the secondary throttle shaft.

The AC idle up vacuum actuator attached to the primary throttle shaft. This is the throttle shaft to the left with nothing attached to it. You would need to use the AC Idle up vacuum actuator from your old carburetor or source a used one from some place (www.sor.com seems to have them for $160 (!))

Got it, thanks!