I am trying to troubleshoot a non flushing toilet. It's been an issue for about a year and I am scratching my head. The cistern fills, you depress and hold the handle, and water rushes out of the inlets and into the bowl, but rather than pushing water through and into the drain, the bowl fills. The strange part is that the bowl drains all the way until there is about a few cups of water in the outlet in the bottom of the toilet. This takes less than 2 minutes or so and If enough time passes after that, it evaporates and its just bone dry.
Yesterday I pulled the toilet. The wax ring was intact, with no apparent obstructions to the drain. The closet flange was clean and undamaged. The drain is a metal pipe, it's clear. To check, I poured a bucket of water into it, and it didn't fill or overflow. While the toilet was off, I took it outside and filled the cistern with water, filled the bowl with water, and flushed using the handle. All the contents of the bowl evacuated along with everything in the cistern. The water rushes out of the cistern rapidly and there are no blockages in the inlets.
I can put a toilet snake through both ends of the toilet and see a clean spring on either end. I did this before the flush test and was surprised there was nothing there.
The really confusing part is, with no obstructions in the toilet, and no obstructions in the drain, why then after reinstalling the toilet, with a new wax ring, if the issue persisting. The bowl fills with a full flush, and drains slowly. I even filled a 5 gallon bucket and poured 3 or so gallons in the toilet, until it filled to the inlets. It drained slowly again. I don't know what to do next.
It's an older Eljer two piece toilet.
Please, any insight will be helpful. I have two toilets in the house, and the other flushes without issue. No clogs or stoppages in any other drains in the house. Let me know if I can answer any questions to clear anything up.