Self Serve Pump Solenoid Problem

[Buzzie8]

I know there are a bunch of posts on lack of pressure on self-serve cat pumps but I couldn't find my symptoms, so here it is. About a month ago my one bay had the pressure drop to about 600 PSI (About 500 PSI lower than I have it set). It was a busy day so after a quick troubleshooting session I turned the regulator pretty much the whole way up to get to 1100 PSI again. Originally I thought I lost one of my phases of power, but I did not. I changed the belt, I changed the pump oil, I changed the pump seals and inspected ceramic pistons (they were good). Today I realized that my low pressure presoak is also high pressure so I thought it was the solenoid that opens to lower the pressure and recirculate water through the pump when on the presoak cycle. I took the solenoid apart and it does energize the magnet when in low pressure. I pulled the needle and seat and cleaned it. I think it is staying open but not sure how to further troubleshoot the solenoid. Actually I am not sure it is the solenoid but it seems to make sense. I hate just replacing good parts without knowing for sure if it is the problem. Any ideas?

 

[thoffmanjr]

The solenoid, I assume, dumps back to the pump inlet right? Remove the hose from the discharge of the solenoid, stick your finger over the hose so the pump doesn't suck air and turn the pump on Rinse. Now you can see if the solenoid leaks by watching the solenoid's discharge. You could do the same thing to the regulator. If it is set to maximum pressure it shouldn't discharge either. I've also seen worn nozzles cause a drop in pressure. Try changing the nozzle too.