Extremely high low, zero high pressure

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Jpittman
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Joined: Tue Jun 13, 2017 5:16 pm

Extremely high low, zero high pressure

Postby Jpittman » Tue Jun 13, 2017 5:22 pm

I recently converted my 90 Miata from R12 to R134-a. I've replaced all o-rings, the expansion valve and compressor shaft seal. After vacuuming I went to charge the system and got some strange results. I accidentally forgot to engage the AC from the dash so I added all 12oz without the compressor running and ended up with pressure on both sides at about 105psi (pretty hot day). I engaged the AC and the high immediately went to 0psi and the low to 130psi. What gives? No, I DO NOT have the gauges on backwards, I promise. Does this mean my compressor is shot? I also suspect my expansion valve may be trash, I bought it from autozone and when I received it you could tell it had been used, someone had put teflon on the fittings, installed it then removed it.
Jpittman
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Joined: Tue Jun 13, 2017 5:16 pm

Re: Extremely high low, zero high pressure

Postby Jpittman » Tue Jun 13, 2017 5:23 pm

Oh also, compressor does not cycle, it runs constant.
Dougflas
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Re: Extremely high low, zero high pressure

Postby Dougflas » Tue Jun 13, 2017 7:38 pm

handwheels on gauges closed?
Jpittman
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Joined: Tue Jun 13, 2017 5:16 pm

Re: Extremely high low, zero high pressure

Postby Jpittman » Tue Jun 13, 2017 8:46 pm

Yes, closed.
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Tim
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Re: Extremely high low, zero high pressure

Postby Tim » Tue Jun 13, 2017 10:32 pm

Low side restriction.
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Jpittman
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Joined: Tue Jun 13, 2017 5:16 pm

Re: Extremely high low, zero high pressure

Postby Jpittman » Tue Jun 13, 2017 10:46 pm

Tim wrote:Low side restriction.

Please explain
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bohica2xo
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Re: Extremely high low, zero high pressure

Postby bohica2xo » Tue Jun 13, 2017 11:20 pm

So you bought a TXV from twilight zone, found TEFLON TAPE on it - and installed it anyway?

Yeah, that TXV is probably more like a plug than a valve.

How did you flush the system? What type of oil did you refill it with? Was the dryer replaced?
Jpittman
Posts: 5
Joined: Tue Jun 13, 2017 5:16 pm

Re: Extremely high low, zero high pressure

Postby Jpittman » Wed Jun 14, 2017 5:41 am

Yea I know, I shouldn't have installed it.
I used ester w/ dye and no I didn't replace the dryer. I know most people say it's necessary but I've seen many conversions where the dryer wasn't replaced and worked fine.

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