Crimp-on splices are way out of spec because you have to kill too much of the twist, and expose too much wire out-of-the-jacket, and they cause a major impedence lump in the cable (expecially at 100Meg).
It would be better to crimp on an RJ45 to each side of the cable and connect them with a coupler.
One thing to watch for as you get your cabling organized, is whether the original contractor used TIA/EIA 568A or 568B components at the outlets and patch bay. The two are similar, except the orange and green pair are swapped (B = pair two is green, pair three is orange, A = pair two is orange, pair three is green).
If you connect a 568A outlet to a 568B panel, the net effect is an Ethernet crossover cable (1&2 swapped with 3&6).
If you're getting link on both ends, the continuity is OK (or you have a short from TX-RX).
Try the network at 10 meg, it *might* work. Put RJ45s on each of the cable-ends (in the closet) and patch 'em together with a hub/switch. That should work.
BTW: '66 blocks are (usually) out of spec for 100 meg as well...there's couple out there, but 110 IDC is recommended (or BIX, Krone, etc...)
FWIW
Scott