Automotive Air Conditioning Information Forum (Archives)

Leggie on Wed June 27, 2012 1:38 PM

Year: 91
Make: Suba
Model: Lgcy
Engine Size: 2.2
Refrigerant Type: CFC-12
Ambient Temp: 70F
Pressure Low: 25psi
Pressure High: 75psi
Country of Origin: Japan

A few weeks ago, I posted about this.
Before: The system was totally flat. vacuumed and charged with 850g where specifications call for 800-900g. The system was pulling a vacuum on low side and only 40-80psi on high (don't exactly remember what it was).


Replaced compressor, expansion valve and fitted with new new evaporator drier. Now, I'm getting 25-30 psi on low which fluctuates up and down 5 or so and high is around 75 psi with the new compressor.

Now get this... the car won't turn on compressor now and I confirmed its getting pressure at the receiver/drier sensor port. Did the sensor get damaged staying in vacuum for a month? I'm not sure why ECU won't activate it. I was going to get to it later, so I charged with 850g of CFC-12 again and activated the system by turning on the fans and jumping the compressor clutch directly.

Compressor: DCW-17. Zexel Diesel Kiki, variable displacement type.
Expansion valve: Four Seasons
Filter drier: Some generic one from NAPA.

Both service ports are next to each other and they're within few inches from the compressor right off of the piping entering/leaving the compressor. So, restriction between ports and compressor is highly highly unlikely.

AND.... STILL no cool. When I pressurize the system to 150 psi for test and pull the output connection on the filter drier, N2 rushes out fairly quickly, so I guess the condenser is not restricted, or is it?


When it was disassembled, evaporator core or expansion valve showed no visible signs of debris even though filter drier was sounded like noise maker when shaken.


The old compressor only let out a few drops when drain plug was removed and turned upside down as well as turning the rotor over. I'm not sure if oil is captive in the unit, but as suggested here, I added 4oz of oil.

I don't know what to do now.

Edited: Wed June 27, 2012 at 2:14 PM by Leggie

mk378 on Wed June 27, 2012 5:56 PM

Upon finding a system "totally flat", the first order of business is to find the leak.

The switch on the high side should stay closed between 50 and 450 psi, and open if pressure is too low or too high.

Also it sounds like the compressor is shot. A variable compressor should never pull the low side below about 20, that's how they prevent the evaporator from freezing.

Leggie on Wed June 27, 2012 7:27 PM

Quote
Originally posted by: mk378
Upon finding a system "totally flat", the first order of business is to find the leak.



The switch on the high side should stay closed between 50 and 450 psi, and open if pressure is too low or too high.



Also it sounds like the compressor is shot. A variable compressor should never pull the low side below about 20, that's how they prevent the evaporator from freezing.


I replaced that compressor with a used compressor from a known good system from a wrecked car. The new compressor holds low side to 20-30 psi, which is normal. The thing is, it doesn't cool at all still. The vacuum pressure was with old compressor that sounded like an MRI machine. I already wrote off the old compressor due to the sound.

The low side pressure is normal. The thing is, the new compressor + expansion valve didn't work even with freshly weighed in charge of 850g of R12 as recommended on plate.

The switch has four pins and I currently don't know the pin-out on it.

I think that system has been tampered with in the past as the connection between evaporator and vapor line was missing an o-ring old compressor didn't have any oil in it.

Edited: Wed June 27, 2012 at 7:29 PM by Leggie