Hi all,
I am just wondering if any of you have an idea of what's going on with my A/C. This is a 1994 940 Turbo and is "new" to me. It has manual controls.

With engine off and cold I am reading about 80 psi on the accumulator so there is a fair amount of r134a in the system.

With engine at idle, the low side pressure is about 22 psi steady, and there is no cycling. The vent temp is nice and cold. Works good.

When the engine RPM is higher the clutch cycles maybe every 5 seconds or so with the low side pressure hovering around 40-45 psi. The faster the RPM, the faster the cycles and the vent temp is warmer than it should be.

I don't understand why I am getting cycles. It must not be coming from the low side switch. The pressure actually goes up (on the low side) and then starts to cycle. What is making it cycle at higher RPM and why is my low side going up with higher RPM. I would think that the low side would drop even lower with more compressor power.( i.e. more suction )

Any advice would be appreciated. Oh, and one more thing. The accumulator is not that cold. On my 740 with r134 it gets really cold.

R Duke