Jdub, i'm having the same issue. Found this on a site today:
or here's the quote:
Ejector pumps are installed with the same procedure as above with two additional steps.
Unbolt the lid. The lid of the ejector pit is bolted down with a foam rubber seal between the lid and the pit. Using a socket wrench, you will have to remove the bolts from the lid to lift it up. And if the rubber seal is too dilapidated to reuse, you will have to purchase a new seal from the hardware store. There are also seals around the pipes that come out of the pit held down by two screws that hold the pipes secure in the lid, as opposed to the sump lid that has the pipes loosely penetrating the lid.
Disconnect and reconnect the vent pipe. When you look at an ejector pit, you will see two pipes coming out of it. Because the ejector pit is airtight, when the pump removes water from the pit it creates a vacuum that would suck out the trap water of the fixtures plumbed to the pit, which would allow sewer gas to permeate the home.
To stop this from happening, a vent pipe brings air into the pit to counter the vacuum, and is usually connected to the main plumbing vent of the house. It is common practice to have a rubber hose (looks like a piece of radiator hose) with clamps on it located on the vent pipe at the same height as the check valve, so that when you disconnect the hose, there is a break in both the discharge pipe and the vent pipe where you can easily lift the lid off. If there is no hose on the vent, you will have to cut the pipe at the same height as the check valve and reconnect the vent with hose or a PVC coupling.