new AC, dead at idle.

[spedigo]

just installed a completely new AC system in my 79.

At idle, in gear, with air conditioning on, RPMs are dropping into the 400s and it dies on me when I try to move.

I can adjust the idle up and that’s all well and good while the AC is running but as soon as you turn the AC off idle is running over 1200 RPM.

I went back to Square one and messed with the timing a bit, but never found anything that worked.
What am I missing here? Something vacuum related when the AC kicks on? Some other switch that’s bad?

 

[Ricko1966]

You should have a solenoid that kicks the idle up when the A/C is on . Search for Air conditioner idle solenoid on google,see what you find

 

[spedigo]

OK, thanks. I found the Edelbrock one that goes with my carburetor and it’s pretty high dollar for $245. Just wondering what other options might be cheaper



maybe this? ACDELCO 2142138

You must be registered for see images attach

 

[CorvairGeek]

Is the A/C working well and was the proper quantity of refrigerant oil added? I've not seen A/C load an engine that badly at idle.

 

[Ricko1966]

Is the A/C working well and was the proper quantity of refrigerant oil added? I've not seen A/C load an engine that badly at idle.

Easy enough to tell if the solenoid would fix it,tune it correctly with A/C off then kick the A/C on and crank the throttle stop screw in.

 

[spedigo]

OK, I finally took some time and read the book. Looks like the original idle solenoid was built into the Rochesters.

there is actually a light green wire in the wiring harness that I’ve been wondering about for sometime that was never connected to anything, and that is the connection for the original solenoid according to the wiring schematic.
One green wire from the pressure switch goes to the compressor and the other to the solenoid. If I’m not reading that right, somebody can please correct me.

 

[Ricko1966]

OK, thanks. I found the Edelbrock one that goes with my carburetor and it’s pretty high dollar for $245. Just wondering what other options might be cheaper



maybe this? ACDELCO 2142138

You must be registered for see images attach

The Edelbrock performer carb is a reproduction of the Carter AFB Model C Used by GM through the mid 60s. Also Mopar used a similiar AFB carb. It's a shot in the dark but see if you can find a cheap used one for an AFB on Ebay. Th8s guy made his own bracket and used a Corvette solenoid.

 

[spedigo]

thanks. my buddy has a plasma table and is gonna cut me an “edelbrock” bracket. found a reasonable solenoid so now i know my plans for the fourth.