u/Electrical_Bison1019

Hello everyone, I have a problem with a customer truck, it’s a loaded summit with air suspension that came from another shop to fix a problem with the PCM, the thing is this truck has been sitting for nearly a year and meanwhile the suspension dropped to the ground, now that the truck runs fine, the suspension will not lift even a millimeter, after inspecting a lot, I tested lines and fixed minor leaks it had, yet does the same, pump activates and after like a minute, it does a “PSHHH” sound and starts blowing pressurized air from the hose I circled, how can I know if the problem is the valve block not sending air to the bags, overpressuring the system and then doing that or if the compressor itself is bad?

This is a 2011 to 2014 F150 with the 5.0, lost compression in one piston, teared down to re-ring and replace that only piston.
Ordered it from the dealer, part number BL3Z-6108-N.
Piston looks the same except for few details, the new one has 2 extra oil control holes and a slight chamfer in the second ring, other than that, looks the same.
How big of a problem this would be? Took this route to save money and to not balance the rotating assembly.