AC Cuts off when RPMs increase

[turtle69mgm]

I've got a delema... (2000 Frontier crew Cab, V6) I have changed my pressure switch (one on the dryer) and the temperature switch (affixed on the evaporator under the dash). Now, after charging, my AC compressor begins cycling pretty frequently as the rpms increase. I watched it with the hoses connected. When the pressure rises, the compresor kicks off (as if it was a bad pressure switch, but it has been changed...) Any ideas would be appreciated!Turtle

[NM50]

The triple switch will cause the compessor to shut off when pressures are too low and too high.Undercharging and overcharging have the same effect on compressor cycling.1.5 LBS is the desired amount of refrigerant.

[turtle69mgm]

If the charge is corect, what would cause the pressure to go high, and thus the cycling. The triple switch has already been replaced.

[NM50]

How high does the pressure go?How low does the suctrion side go?

[turtle69mgm]

Low side drops to around 25, high side starts going above 375 around 2500 rpm. Was thinking possibly expansion valve or maybe the compressor it self. When the original tripple switch first broke (bird hit grill and cracked switch), I jumpered it for a few days until the new switch came in. So for about 200 miles of driving, the compressor (and aux fan) ran constantly, but stayed cold, of course. It was in the middle of the summer with temps in mid to high 90's. I appreciate any insight!!

[Desert Rat]

We had a similar problem on our Xterra and found the system was overcharged. It was fine after letting go a little freon.

[NM50]

The low side usually kicks off around 20 to 25psi.The high side is normally 175 psi.375 is way too high.It sounds as if there is a restriction in the line but high charge volume can cause the same effects.

[turtle69mgm]

Where should I look for this problem? The vehicle has 150K miles, but the AC system has never had any problems until after the triple swich was broken... replaced the switch, evacuated the system, and recharced (1.5 lbs, as per service manual). Worked for a while, then wouldn't stay on. Determined the temp switch (one mounted on the evaporator) was bad, changed that, worked good again for a while. Now the pressure problem. When I hooked up the hoses, i saw the pressure getting high. If you increase the RPM to around 2200-2500, the compressor clutch disengages. What about expansion valve?

[NM50]

The expansion valve is usually the culprit for blockages.