I have a 85 XJ6 with the 4.2 liter. I evacuated the AC system and installed a R134 retro fit kit. Started out with no problems, I sucked the system down and it held its vacum perfectly. I installed the oil then started putting in the R134. After putting in 3 - 12 oz cans of freon, the low pressure side built good pressure (40psi). Whats odd is that the high pressure side did not show any pressure at all. I live in MN so it is still a little cold out but I did this work in my heated garage and had 52 degree air coming out of the vent.

How many 12 oz cans of the R134 should this system hold? Why do I not have any "high" side pressure?

Also, the AC pump comes on when the fan is turned on and runs continious. Shouldn't the pump cycle?

Thanks for any help!

 

I'm not an A/C expert.....but maybe the expansion valve?

The compressor runs in all modes, including heating modes, by design. All incoming air is first refrigerated and dehumidified, and then heated as needed to maintain the desired cabing temp. The compressor will cycle on/off if the evaporator core ices up...there's a thermostat with a thermocouple in the evap core for that.

After you fix the pressure problem you can test the system in cool weather by tricking the system into thinking the cabin is hotter than it is by heating the cabin temp sensor...it's in the lip of the padded dash right above the glove box door. Use a hairdrier or even the cigarette lighter (the car's cigarette lighter...not the kind with an actual flame used to light your Pall Malls!). This will force the system into max cooling.

Good luck
DD