I just recharged my A/C. The PO did the 134 retrofit kit, and there are no major leaks that I can find. The system seemed to be completely empty, so I put in 36oz. The fill gauge was reading around 40-45 (not sure what the unit of measurement was) and was in the "green zone" on the gauge.

My compressor kicks on at idle, and will stay on for 45+ seconds at a time before cycling off, which is normal behavior to my knowledge.

However, when I drive the car, at any RPM above say 1500, the compressor cycles at a 3-5 second rate... 3-5 seconds on 3-5 seconds off... Is this normal behavior in these cars? Is this indicative that it needs more refrigerant, or less refrigerant?

My carburetor needs a rebuild, which is leaving me kinda low on power to begin with, and the constant power drop off / surging from the compressor cycling is quite annoying on the highway.

Any tips or advice is appreciated

 

When checking compressor cycling, it should be done at a high idle but I'm not sure the best way to test that with a gas engine. Normally, the compressor should cycle on for a minimum of 7 seconds. Any less and it's probably low on freon. Can't make a good guess without seeing pressure gauge readings.

If you had no freon in the system and charged it up, there's a good chance that there's now air in the system. Air is a non noncondensable and screws up the efficiency of the AC system.

Ways of checking for leaks is with a freon sniffer or charging the system with nitrogen and spraying everything with a soapy water solution to look for bubbles. If your system leaks, your charge will soon disappear and you'll have no AC again.

 

When I started, the compressor wouldn't cycle at all, but after about 10 seconds of adding the 134, it kicked in.

There was good vacuum on the low side before I started to fill it, I can't remember the reading I got on the gauge, but seeing there was a vacuum, I figured there wasn't any air in the system.

I guess then my main question is how much 134 these cars normally hold. If it's quick cycling could mean it's low on refrigerant, I can always get a little more if I know how much more to add.

Besides the quick cycling (and resultant feel of loss of power due to under-performing carburetor), the A/C is performing wonderfully, I'm getting Ice cold air out of the vents at all speeds...