Charging 134a

Ok I went out and bought some manifold gauges, I do residential work so I thought I could maybe make heads or tails of it but no. my first problem was when I would idle it would blow warm air then get colder as I would drive. I originally put the gauges on and the liqiud side would fluctuate as it would kick on and off and the suction side was way too high it would only pump down to like 60 or 65, so what I did was recover it, then when I began charging it just while idoling I got the suction side back up to 35 and the clutch would stay engaged, and blow cold air while idoling, great fixed first problem. Now when I rev it up the suction side drops to below freezing, somewhere near 27 or 26 on the gauge the clucth kicks off until it gets back up to around 35, kicks back in, then drops and so on and so forth. If this makes any sense to you please enlighten me, because my wife is tired of hearing "this just baffles my damn mind!" Thanks for any help. Telling me I am stupid is not welcome unless you have a solution.

have you checked the cycle switch? sounds like it may be sticking. Might also want to check the orifice tube for debris.

but the pressure should be around 35 idoling, how low should it normally go while driving,

Theres a great pressure chart you can get from your local auto parts store. the chart will give you the low and high side pressures for the ambient temperatures when charging. Typically, at 1700 rpms, the low side pressure should be around 35-45, high side 220-240, with ambient temparature between 80-90. Higher pressures if higher ambient, or lower pressures with lower ambient. If you over-charge, it will not cool well. Rule of thumb is once the low side line gets cool and begins to sweat, your 134a system is full. 134a runs at higher pressures than the R-12. make sure you only hold the 134a can up-right, and dont push or rush the charge, because you can damage the compressor. I live in Texas where the temperature runs in the triple digits, and the AC runs almost everyday. Good Luck.

hey thanks alot man, we are in texas as well so 100 is not rare