The symptom was rapid cycling of the compressor clutch. Unfortunately there does not seem to be a high-side pressure test port on the R-134A 1993 Volvo 240s. Weird. Without the test port of course it wasn't possible to check for excess pressure.

Several online resources suggested that the orifice tube might be plugged and/or the accumulator gunked up. Since both appeared to be the original units I replaced them and did an evacuation and recharge. Still the compressor fast cycled.

After much electrical troubleshooting I finally discovered that as some point before I got the car someone disconnected the ground wire which is supposed to ground the compressor to the block. The clutch circuit was thus only getting a highly resistive ground though a leakage path. Cleaning and reconnecting the ground wire gave me a system which works like new. I'm surprised that the clutch worked at all without the ground attached, but there ya go.

One thing which made all of this easier going is that Harbor Freight had their A/C gauge set on sale for $30! It is an amazingly good unit for that price:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92649

John

I for one appreciate hearing when a problem is solved - especially when it is something as simple as a disconnected wire. THX for taking the time to post back.

How did you evacuate the system? Take it to an A/C shop?

I met a guy who said that he made a pump-down tool from an old refrigerator compressor, but I have not had the ambition or skill to try it.

Ah, good question. I used another nifty $10 tool from Harbor Freight which attaches to the gauge set at the yellow line:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92475

For $40 plus shipping I now have a gauge set and evacuation pump. Works like a charm, though it does keep my compressor running almost flat out to drive the venturi type vacuum pump. I have a commercial vacuum pump I picked up on ebay a few years ago with plans to put together a vacuum veneering setup for my woodshop, but it was quicker and easier to pay $10 for the Harbor Freight gizmo then it was to sort out the plumbing to hook the real pump up to the gauge set.

John

Good on ya, Jack. Now's the time to ask I suppose, did you ever resolve your dispute with "the supplier on the East Coast"? The lightweight dryer?

The dryer is undersized. I didn't want to open the system again to replace it, so I wrapped a thin layer of high density foam around it to make the bracket fit. Sometimes stopping what you are doing and leaving a car in pieces for the 1-2 weeks it takes to do a cross-country part return isn't worth it. I'm still not ordering un-branded parts from FCP or any other mail order source. Sometimes a bargain isn't.

John, not Jack

I used FCP's Volvo sourced R134A retrofit kit for our 92 245, and all was up to snuff.

jorrell
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89 244 171K miles, 92 245 241K miles, 06 XC70, 00 Eclipse custom Turbo setup