I replaced my ejector pump about a month ago and have been having trouble ever since. It will hum like it is trying to go off but never actually discharges. Then when I release a little pressure from one of the rings holding the check valve in place. It will go off then. When I release the ring a little puff of air comes out with some sewage then like I said it goes off. I have taken the check valve out and looked at it but everything looks good. It is a simple flap valve not a srinp loaded one.

I doubt it is the "back pressure" that keeps your new pump from pumping. First: did you replace it with same HP pump ? Also, your check valve may be bad. I would remove check valve, attach hose to the pump discharge and gave it test run. Moreover, once you are inside the pit, take hose and hose it down. Vacuum all debris from the bottom and put new pump on two bricks. Back to you. Milo

Milo makes some very good points. If the pumps just hums then something's preventing the impeller from turning.
Either the HP is too small or you failed to elevate it up on a couple of bricks and set it down in all the debris and it's clogging the impeller . Milos advice is solid. Follow it. Good luck, Tom

Milo certainly raised good concerns.

I'm also wondering if you have a hole drilled in your discharge piping (under cover, in pit). If there is no hole drilled in the discharge piping then the pipe could be AIRLOCKED and that would cause the same issues you describe... ;)

See drawing.

Let us know more, OK?

Mark