Have a pump system for bathroom underground level, just replaced flush ,water saver type, in above ground bathroom.
Now when pump activates downstairs the flush and tub upstairs makes a gurgling sound and the water in the toilet raises slightly for an instant
This did not happen with the old flush 70's vintage
What is going on

Hi Max

Sounds like you are connecting the toilet installation to an issue with your drain lines. Here, I don't think there is a connection as much as there is a coincidence in timing is all!

By your description, it sounds like the drain line the ejector pump and the upstairs bath (main drain?) connect into is getting partially clogged. I would check that out before the line totally clogs and you find out AFTER the ejector pump pumps a whole pit full of "stuff" up and into your house upstairs... UGH!

Look around for a cleanout plug after the ejector connection into the drain pipe and then remove it (unplug ejector, too) and then run a hose on full into the cleanout and see if you can get the drain to back up in any way. If that doesn't show anything then fill a tub and drain that... see if that causes things to back up the drain line (have someone upstairs to stop the tub from draining completely just in case the drain does back up). If the drain backs up then the drain line needs to be cleared/snaked to resolve your issue!

Check this stuff out... let me know what you find, OK?

Mark