So it looks like it should be a 4 ohm load the amp is expecting so the speakers should be 16 ohms each.
Do the speakers have an ohm spec on them? Do they say 8 ohms or are you assuming?
I would start by un-soldering all 4 speakers and measuring them individually at the speaker with no wiring attached. They all measure about the same.
If they were 8 ohms, the reading should be less then 2 ohms (like 1.x).
2.3 does seem on the low side; what type of meter are you using? is it set to the lowest setting for ohms?