A/c compressor not engaging at idle (1 Viewer)

[60 s]

Hey all,
My Fj60 got a carb rebuild last summer and a/. Fix. The ac blows cold above 1,000 rpm. After the r the rebuild the compressor won’t engage at idle only after 1000 rpm. Also before it would rev up when i turned it on. What could it be?

 

[LandoNick]

Idle up all in working order? AC amp? stock carb and smog?

 

[60 s]

How do I know if it’s in working order? What’s a/c amp? It’s the stock carb i rebuilt it to pass Cali smog which it successfully did.

 

[LandoNick]

Does your VSV have vacuum to it? its the plunger looking thing on the front of your carb. There is vacuum lines that runs to it from the VSV from the driver side fender the other tube from i believe manifold vacuum

 

[LandoNick]

Top picture the idle up plunger thing.
Second VSV
THIRD ac amp

 

[60 s]

Yes it does have vacuum. The linkage idler thing, what is that? What’s that screw and linkage there for?

 

[LandoNick]

Vacuum when the ac is on?

 

[pithicus]

Might just need the idle up screw screwed down further. Mine has to be screwed all the way to get the idle up fast enough.

 

[LandoNick]

Might just need the idle up screw screwed down further. Mine has to be screwed all the way to get the idle up fast enough.

Ac idle up should be at 1,000 rpm. When compressor on.

 

[pithicus]

Ac idle up should be at 1,000 rpm. When compressor on.

That's about where mine is.
When @60s carb was rebuilt, the screw might have been left unscrewed
Sorry, should have explained better.
Everything is working ok, except the idle up speed adjustment screw is not screwed down far enough
stopping just short of touching the lever that opens the butterfly a tad.

 

[60 s]

Thanks! The screw needed some adjustment and now she’s good

 

[OSS]

 

[4runner2FJ60]

Just read this thread and am also having ac issues. My cruiser is new to me last October and i have waited until the hottest part of summer to figure out what is wrong with it.....OF COURSE>
Today i checked these things in this thread and found that the VSV has vacuum to it, yet when you push the ac button there is no vacuum to the idle up plunger. Since i have no history on this truck, i am sure there is more than just one issue with the ac. I can trick the ac amp to click if i hold the accelerator at 1000rpm or higher and push the button. The blue light used to come on, but stopped so i assume that is just a light bulb. My fuse is intact.
So do i start looking for a new VSV switch? Any advise appreciated. Thanks

 

[LandoNick]

Just read this thread and am also having ac issues. My cruiser is new to me last October and i have waited until the hottest part of summer to figure out what is wrong with it.....OF COURSE>
Today i checked these things in this thread and found that the VSV has vacuum to it, yet when you push the ac button there is no vacuum to the idle up plunger. Since i have no history on this truck, i am sure there is more than just one issue with the ac. I can trick the ac amp to click if i hold the accelerator at 1000rpm or higher and push the button. The blue light used to come on, but stopped so i assume that is just a light bulb. My fuse is intact.
So do i start looking for a new VSV switch? Any advise appreciated. Thanks

Put power to the VSV. if you hear it click it should be good.

 

[pithicus]

Is the a/c cold? Compressor won't engage if it's out of gas. If the vsv is ok, the amplifier might be faulty, and not sending the signal to the vsv.
There is a low pressure switch on the evaporator. The low pressure could be what's stopping the blue light, and everything else from working properly.

 

[4runner2FJ60]

a/c is not cold at all. Probably out of gas. Thanks for all the info. I was thinking the idle up would just happen when you turn on the ac regardless. I'll see if VSV works with power. Thanks

 

[4runner2FJ60]

Put power to the VSV. if you hear it click it should be good.

@LandoNick
I finally got power to it and it does click each time I add 12volts. What should i check next? I guess it might be easiest to get an AC shop check for leaks and charge it? It is the old r12 gas. $$
Also in your pic, did you relocate your VSV to the side fender wall. It is in a terrible spot under the carb fan outlet in terms of getting to it, I like where yours is.

 

[DrRock]

I just got my ’85 and my AC didn’t function at first. First thing I looked at was the compressor and as it turned out there was a label on the back with a part number. I punched this in to google and it confirmed the compressor model and what type of refrigerant it was designed for. In my case it was r134a so I topped the system off and so far everything is back to normal and I’m getting nice cold air in the cabin.

punch line here is get to know what might have been done to your truck in the past if you don’t have records from the previous owner do some digging in the engine bay and go from there.

cheers, James

 

[4runner2FJ60]

@DrRock Yeah i knew about the refrigerant by the connection it has, but the tag is a good way to check as well. I think that is my next thing to do. Probably take her into an AC shop to leak check and or top off the charge. Not worth buying gauges etc...to me. Does anyone know if it is cheaper to charge the r12 or convert to r134?

 

[pithicus]

I you can't find any R12 There are other options. Hydrocarbon refrig's like duracool for eg. R134a is getting phased out this year, but a/c shops will have the skinny on what gas to use or convert your system to.
Hint. I used a hydrocarbon refrigerant as a direct replacement for r12 without converting anything.