Ac Compressor Operation Questionable?

[lexus082]

Here's the deal. I added 134A refrigerant to my sc400 which has a sticker that says DENSO 134A only. I bought a can of 134A and it came with a hose and a gauge on the can. It stated less than 25psi "low" 25-45psi charged. I was just trying to get mine up to 25 and then I was going to see how that felt. I wasn't trying to do the max 45. Just enough where it would be the (minimum charge) of 25psi according to the can of 134a. So I hooked it up and I filled it up to 25psi and stopped. As soon as I got the gauge up to 25 psi, (I believe) the clutch disengaged (AC was still on coldest setting on max). So after that (re-charge) to reach 25 psi. the "clutch" (if thats the correct part name) disengages and engages on its own several times a minute. This is still with the AC set to the MAX COOL setting. Why is my compressor (clutch) suddenly engaging then disengaging on its own??? I did the self test and the only one I had blink on and off again repeatedly was code 21 which is the solar sensor. But again something doesn't seem correct. Everything was working mechanically ok before I added the 134a. Just my luck that something would happen. Deep Breath.... ahhh. Nope didn't work. Any help would be appreciated greatly as always.

Also... While installing the hose from the can of 134a I bought to the Low Pressure side it took a while for me to finally get it snug. It looked like the fastener to temporarily lock the hose onto the low pressure port was somewhat damaged internally and maybe perhaps I let freon escape and thats why its cutting on and off. Does anyone know what the correct pressure should be in (PSI) for a charged system. I hope its just low and thats what is going on. Is it 35 PSI (max)?

[lexus082]

Well I found out why the compressor was engaging and disengaging on its own repeatedly. This happens when there is low refrigerant in the system. I guess I had some leak on when I was trying to add the refrigerant from the can I bought. I think the valve on the hose that connects to the Low pressure line was faulty and allowed it to leak out. But since I found out I thought I would share this with you all in case it ever happens now you might know why.

[jzz30]

typically a 134 system low side pressure is about 35psi. 45 is a bit high. and reguardless of your fan speed your clutch will turn on and off.

[lexus082]

Thanks you always have the answer. Its cycles on and off within a short amount of time repeatedly when first turned on. I didn't want to cause any damage to the compressor if it was low on compressor oil/refrigerant. Hopefully when I have time I will get it to 35 psi and will post my results.

[jzz30]

oh yea if it cycles on quickly then the pressure must be on the edge of being too low. but yea post your results!!

[lexus082]

Well according to the manual I checked to see what the specs are for a "normally functioning refrigeration system" and it states Low Pressure Side (1.5 - 2.5 kgf/cm2) and High Pressure Side (14 - 16 kgf/cm2).

My question is mine currently is approx. 2kgf/cm2 on the low pressure side, if I got it up to the normal max. of 2.5kgf/cm2 would I notice any temperature change of the air coming out of the vents??

Also, today was around 87* F and the air coming out of my vents was 55* F according to my thermometer. This temperature reading was obtained while driving, ac on coldest & on max fan speed. Last night I got it down to 50*F at idle

Now I just have to compare to my sister's new car and see the difference in temperatures at the air vents.

[jzz30]

honestly i cant answer that question but if max is 2.5kg then fill it up to a little less than that and measure if there is a difference. but do the measurement back to back. if it doesnt make a difference then take it back down because i think it should be in the middle of the acceptable range because pressure does fluctuate with temperature. PV=NRT or sumthing like that right?