Well, all is not as well as I thought with my 93 Civic's A/C. I recently repaired some wiring on the stock Sanden TRF090 compressor and checked the field coil resistance and power continuity... everything checked out to spec, so I installed a new drier, installed the newly fixed compressor, put 4.2 oz. of oil into the system (4 oz in the compressor and .2 oz in the drier), bolted everything down, had a shop pull a vacuum on the system and recharged it with 21 oz. of R134a.

When idling, the A/C *will* blow somewhat cold and generally delivers a temperature of around 55F/13C when the ambient temperature outside is 90F/32C. However, if I open the throttle a little bit and rev it, then let off the throttle, the compressor will do something odd... it will cycle off/on VERY rapidly anywhere from 1-4 times within about 2 seconds, then resume spinning like nothing happened. While it does this, the delivery temperature shoots way up. The end result is that the A/C blows relatively cold when idling or during highway driving, but is almost non-existant in stop-and-go city traffic.

What is this super rapid cycling after throttling indicative of? I haven't gotten a set of manifold gauges to measure the high/low side pressure yet. I'm just looking for possible causes at this point

 

Does the condenser fan run when the A/C is on?

 

What is the engine idling at when the a/c compressor kicks on? It doesn't seem to idle too low does it?

 

The condenser fan does run, yes.

The engine idles at ~700 when the compressor is running. Though the engine vibrates a bit more while the compressor is running, as well.

 

What direction does the fan move the air?

 

Inward, toward the engine bay.

 

I will also add that when I had the compressor out to repair it, I found the gap between the armature plate and pulley to be too close after reinstalling the pulley. I added a couple of shims and now it's on the low side of spec. The current gap is .015 in. (spec is .014 - .026 in). Not sure if I should add another shim so it's more towards the middle of the spec range, or if it even matters.

 

The clearance sounds fine.

Hook up a manifold gauge set to measure the high and low side pressures with the engine idling at 1500 rpm and the A/C running on max.

Post the pressures and the outside temp. See FAQs sticky.

 

Yea, I'll need to go pick up a set of those next time I get paid and put them to use. I'll report back in this thread with my findings when I do.

 

Seems like it might have a bit too much freon, also on some cars if the idle dropped too low the compressor clutch will disengage in an effort to raise the idle to something suitable. So check your idle also.

 

before you jump to any conclusions, check pressures on max a/c and post high/low pressures at 1500rpms and ambient, as stated above.

adding, dumping freon will just change another variable.

 

Well I suppose double checking and/or adjusting the idle RPMs won't hurt anything so I'll do that while I wait on my manifold gauges to arrive. I bought some manifold gauges online, so they'll be here in a few days. And, no, I don't plan on adding/dumping refrigerant until I find out what's going on with the compressor.