cobra II high pressure pump cavitation

Our high pressure pump (cat3535) started cavitating 3 days ago. We have check every swivel and every hose and there are no leaks(water or air). The pump only cavitates during the High pressure soap and wax cycle and pressure gauge drops from 1100 to 750 psi. It runs smooth and quiet during the two high pressure Rinse cycles at 1100 psi. We have only one guess that it could be in the Danfoss Solenoid Block 2 solenoid may be sticking. Any help please

Not familiar with the cobra but I think you're on the right track. If the pump is starving when wax and soap is running, look for a problem in plumbing common to those two functions. Wish I could be more help.

Thanks GregPack: We replaced both lines for soap and wax and checked solenoids. All are in better shape now then ever.

Not familiar with the cobra either. It sounds to me like the solenoids are activating since you're only getting an erattic pump during the two functions. It may be sucking air. I would look for some type of air leak before the solenoid valve. Either the soap and wax levels are below the suction or you may have a cracked fitting or hose causing the pump to suck air.