AC problem (high side pressure)

[asp84]

Just hooked my AC up on my conversion car:

I have a: (Explorer with a 94 5.0L V8 in it)
- 1994 Explorer R-134A Accumulator (brand NEW)
-1994 Explorer R-134A Evaporator
-1991 R-12 Condensor (front of car)
-1994 R-134 mustang compresssor (panasonic rotary vane)
-1995 Mustang 5.0 Compressor lines
-Brand New clean Orifice tube

THe problem: My High Side Pressure is over 450 PSI!!!!! My Low side presseure is also abnormally high. Since I just today replaced my Accumulator and evaproator tube, soemthing else has to be the problem. NOTE: My old orifice tube did not have any crud on it, or show any the signs of black death.

Could a AC compressor that is goign out, cause this much pressure? or is it a clog in my system? I understand it is either my condensor or Air Compressor, i'd like to narrow my chances of buying the wrong part though.
Thanks,
Al


Note: he originally put in 2lbs of r-134, and then evacuated the system under vaccum pressure, and put in only 1.5Lbs to see if it would reduce pressure...........it didn't

 

[TDG]

Sounds more like the condenser to me, or low airflow through the one you have. I'm guessing that the compressor never shut off?

 

[asp84]

compressor stayed on the whole time ........(I've got the High pressure cut-out switch disconnected. Although the needle was starting to shake when it got near 500psi.

 

[TDG]

It sounds to me like there is something wrong in the condenser area, either not enough airflow or it's plugged pretty bad.

I'm guessing that when the high pressure vapor leaves the compressor and goes through the condenser that it's not coming out as a high pressure liquid but rather as high pressure vapor, the orifice tube will not have much of an effect at dropping the pressure of vapor as it normally drops the pressure of liquid (hense the high low side readings) this high pressure vapor is then works it's way back around to the compressor where it helps to drive the outlet pressure even higher. Of course it never shuts off since the pressure on the low side is never low enough to trip the clutch cycling switch. Like I stated above this is just an educated guess, maybe one of the AC techs on the board can elaborate more.

 

[asp84]

Sounds like a good guess. The Mechanics at the shop are pretty clueless. They have a solution to the problem. That is: Replace everything and charge me a $1500 bill. No thanks. Well, It looks like I'm heading down the path to replacing the condensor, since that is only $140 to replace. Then compressor (which costs $300)

If anybody else has suggestions please let me know!

Al