A pulsation dampener doesn't keep the pump from pulsating. It's to smooth the normal operation of the pump. If you can feel it pulsating in the bay and you have pulsation dampeners installed and working properly, there's likely something seriously wrong with the pump.
You don't normally "charge" the pulsation dampeners, they come precharged. They should have 500-600 PSI in them, or half the operating pressure of the pump. You'd have to take them to a specialty shop to charge them.
I mentioned above about the inlet flow and noise - again, if the pump isn't clattering loudly with the trigger pulled, the flow is fine.
Like I.B. said, look at the pump. See the sticky at the top of the General Discussions sub-forum for pictures of a washed-out manifold so you know what to look for.