cut-in switch for a/c on 308

I have my local mechanic doing some stuff on my 308 GT4. he's pretty good on air conditioning. He thinks there is or should be some kind of switch which raises the idle when the a/c is turned on. Is there such a thing?

 

Your mechanic is wrong.

The 3x8's CIS system does not have a mechanism for increasing idle speed when A/C is switched on.

Lots of cars either boost idle speed, or open the throttle a bit to keep idle speed constant, when A/C is enabled. However, they have electronic injection & the ECU does it. I suspect the 348s & newer might have this feature as it's easty to do with electronic injection.

 

That makes sense. I guess if there were such a switch on a carburated car it would have to be mechanical, right, and that would be hard to do. thanks.

 

Hi,

Strikes me it should be easy to rig a wide-open throttle cutout switch for the A/C, perhaps from parts from other car, or just a microswitch mounted on a carb that operates a relay to cut on/off voltage to the A/C clutch. Ditto to reverse it's operation so it cuts off the A/C when at idle. A little different and cruder way to tackle any resulting idle problems, but pretty simple to rig.

Art
79 308 GTS

 

On earlier carb cars (US) they used to have a solenoid on the throttle linkage when you turned on the AC it would extend a plunger and the idle would increase by about 100-200 RPMs. You can do this if you build a bracket and just go buy a solenoid . In fact You could mount it to where you remove the dizzy idle switch and wire it to the compressor. But what I do is adjust the idle to 1100rpm and it works just fine. With the AC on at idle it runs at 1000RPM. Simple

 

What he said.

However, if you are having a problem with idle when the AC is on, there may be something else that needs to be adjusted. Have you synced the carbs?

Mark

 

once I get the car back (was having the steel braided brake lines installed, and the a/c worked on, I'll take on synching the carbs per the instructions from that other site.