R12>R134a conversion: insufficient cooling

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, Dougflas, HECAT

PromiseRing
Posts: 24
Joined: Thu May 24, 2018 2:28 pm

R12>R134a conversion: insufficient cooling

Postby PromiseRing » Mon Jun 03, 2019 2:15 pm

1993 Toyota pickup truck, 22RE. I’ve installed a whole new AC system into this truck including new: condenser, evaporator, TXV, receiver drier, compressor, etc, and flushed all lines. Installed all new parts with pag46 oil.

So, I had been having performance issues with this truck last summer after all the work, and decided to look at it finally. Here are my test results.

77F ambient temperature, at 1500-1800rpm I’m getting 25psi low side and 200psi high side. This is with a LOT of airflow over the condenser, and the clutch fan fully engaged. There is no chance this is an airflow issue, since i was moving so much air and results are the same on the highway. 57F absolute coldest temperature from the vents. 20F drop over ambient.

At idle, I’m getting 33psi low side, 170psi high side, again with fan clutch full engaged so lots of airflow. Vent temps 57F.

What should I be looking into? I would expect temps closer to about 40-45F.

Oh, and before I got these numbers, I evacuated the system, vacuumed for 40 minutes, let sit for 20 minutes, then vacuumed another 20 minutes.
User avatar
Tim
Site Admin
Posts: 276
Joined: Tue Apr 12, 2016 2:19 pm
Location: Scottsdale, Arizona
Contact:

Re: R12>R134a conversion: insufficient cooling

Postby Tim » Mon Jun 03, 2019 3:50 pm

Hot water shut off valve may be leaking.
------------------------------
Please support ACKITS.com for your Auto A/C Parts and Tool needs.
P:602-233-0090
PromiseRing
Posts: 24
Joined: Thu May 24, 2018 2:28 pm

Re: R12>R134a conversion: insufficient cooling

Postby PromiseRing » Wed Jun 05, 2019 12:21 pm

Tim wrote:Hot water shut off valve may be leaking.

Hi Tim, thanks for the reply. I will check into this next time I am near the truck.

Based off of the pressure readings, is there a way to tell what the vent temperature should be close to?

Also, the only things I'm not really confident about with this AC project was the TXV bulb placement as well as evaporator placement (I think hot air may be getting in from the engine bay).

Is it possible that I have a TXV bulb placement issue, or do the pressures I posted suggest that it is doing it's job? Thanks

Return to “Automotive Air Conditioning Forum”