Sometimes when you take the solenoid apart...as you reassemble it...if you don't go slowly...the Large Pilot Valve O ring can roll out of its track. This will present the symptom that you describe.
One reason I always tell everyone...take your marker apart ONLY when you need to. So many people are OCD and feel a need to fully strip the marker after every time out to play. This is Overkill! The marker will tell you when it needs attention.
As Uziel has indicated...it may also be down to the bolt assembly...more precisely...the O rings on there. make sure you are using the correct O rings as outlined in the manual.
Finally...if the Spool Pack O rings are worn out...you may have to change them. You won't be able to SEE anything abnormal with them unless one is torn. If your marker has a large number of shots...the inner tolerance of the solenoid manifold may be worn around the spool...or the spool may be binding up.
These are all I can think of...other than the most common problem...a cheap or worn out battery!
You broke it didn't you!
I Love that it takes longer to open a package for a repair on an Ego than it takes to actually fix the gun!
For the Love of Paintball....Use OILon the rammer!
If you THINK you're a Super Hero...You're NOT! SLIDE RIGHT!!!