92 Civic with 192,000 miles.

I been trying to evacuate & recharge my ac system for the last 2 days. I replaced the relief valve on the compressor(it was blown-out before I brought my car) & replaced the drier.
So last night I vacuumed the system(Hi & Low side), and saw it kept a vacuum for 3-4 hours(after I turned off the pump)..the reading were -28psi(LO-side) and 0(HI-side), then I recharged with r134 freon(converted from r12) on the LOW SIDE of course using a Manifold gauge with the AC on full blast.

I sat there for almost an hour shaking the can(about 18oz) when the compressor kicked on....well that was a good sign..no crazy sounds from the compressor either...At this time the LO-SIDE was 50 PSI..and the high side was about 150 & the can was only 1/2 empty.

I wanted to test the compressor alittle, so I turned off the AC for a sec & turned it back on....compressor never spun again. Also there was liquid freon in the Manifold sight glass..I NEVER turned the can UPSIDE DOWN at all..isn't it suppose to turn into a gas as you shake it?
Then the CEL came on & the idle was going back & forth from 800-1200 every 15 seconds.

Can anyone help me out here? I'm not sure what's going on with my ac system or why it's acting a fool.

Also.....Does the AC system or Freon have ANYTHING to do with Overheating?

 

Did you change the oil in the compressor? Do you know if the car was converted before or was it still set up for R-12 when you started?

What are the pressures now?

Does the condenser fan come on when you press the A/C button? Does the engine rpm change when you press the button vs not?

There is supposed to be liquid refrigerant in the sight glass. That's how the system works, it moves heat by changing the refrigerant from liquid to gas and back again. The compressor only handles gas, but under pressure the refrigerant turns into liquid (i.e. condenses) as it gives up heat in the condenser.

 

Well the pressure was 50 psi(low side) while it was charging, this was while the compressor was spinning.
When it stopped spinning..it went to 75 PSI(low side), High side is about 150.

The Condenser fan does come on, It was on the whole time I was recharging(with the AC on full blast). It still comes on tho when the AC button is pressed.
The Idle changes when I don't press the Ac button in, which I didn't understand why.

Right now I'm vacuuming the system again because I thought something was wrong when I saw Liquid freon in the manifold sight glass...But you say that's regular. Does that mean I should just try to recharge with another can of Freon? I have another 14oz..and alittle of the 18oz can left.

Also..the Freon comes with the peg oil in it & I converted(R134) the system myself about a year ago, it was originally r-12 when I brought it.

 

Fan on and engine revs up means the ECU has everything "go" to engage compressor, it must be the compressor relay or clutch. Very common for the air gap between the pulley and plate to be too wide, this causes the compressor to not engage particularly after the coil gets hot.

Be careful about using too much oil, it's best to use plain R-134a for charging after putting any necessary oil in as a liquid with the lines open. On conversions the PAG oil tends to foam up making the sight glass useless so don't look at it. Charge by weight with the same amount that was specified for R-12.

 

Alright so basically i need a new compressor, well..a rebuilt one anyway.
But i still have another issue which is odd after i failed to recharge the ac system. This morning i started up my civic and it kinda struggled to start up..i started up again and same result(kinda struggled), didnt think much of it. Drove for about 7 minutes and the cel light came on and stay on the rest of the way for about 15 minutes, there was no performance issues at all while driving. It pulled up a code 43..which is the o2 sensor if im correct. So do i just replace the o2 sensor or just troubleshoot alittle more in case its something else. O2 sensor has not been replaced since i had the car for 18 months. I haven't had any o2 issues since i brought the car. My daily mix of city & highway driving has an avg of 31 mpg btw.

 

Something I noticed in the posts was the pressures. When the compressor is off the pressures should equalize. You may have a plugged orifice. Did you flush the system when you switched freons?
Many times R-12 compressors don't last after a change over. I agree with oil too much is not good. Also using R134A will take less than R-12. If you overcharged you may of damaged compressor. Also overcharging synthetic freons will cause the evap. temps to rise. So you need to look up the conversion for R-12 to R134A so you don't over fill. You can't fill A/C units with the new freons like you could with R-12. Also you need to measure your oil also. Too much will cause higher temps.
I'm an ASE Certified refrigeration tech & Type I & II high pressure EPA certified. For Commercial units.