Will there be toilet problems?

I recently received some really great electrical guidance on another forum (electrical) so I hope I can get some help here on a toilet installation. I am about to remove the old toilet in downstairs bathroom and install a new one. It will be off for a few days at least while I tile. Here's my question: if someone flushes the upstairs toilet, which is essentially directly above the toilet to be removed, will anything come out the pipe where the toilet has been removed?
I think the downstairs toilet bottom is only a few feet higher than the pipe to the septic and it has never flushed that great. When it flushes, it fills nearly to the brim but usually eventually goes down after spiraling around 20-30 times in slow motion. When it is swirling, it makes a sucking/swirling/gurgling sound. Thanks in advance for any help!

 

If the line isn't partially clogged it should be okay but best to put a test plug where you removed the toilet to keep out sewer gas.

 

I agree with Ray. Sounds like you may have a partial clog. I've only used a rag stuffed in the pipe to keep out sewer gas never considering back flow from toilet above. Test plug is a good idea but I would look at the flush problem before finishing that bathroom. Any flush problems with the old toilet in that location? Now that you have total access to sewer from removal of toilet you might want to snake the drain from that location.

 

Maybe just try dumping a 5 gallon bucket of water down the open pipe quickly to see if it has a good flow?

- Peter

 

Thank all of you for responding and the advice is appreciated!