how exactly is the loom configured, to pick up one side of one of the coils to drive the tacho = should be if you are running the rs2K tacho, or from the pin at the ecu as per std install using original tacho via the original wiring at the coil back to the tacho?

an easy test would be to hold the car at around 3K revs, and get someont to disconnect the multiplug from the coilpack. if the rev counter drops to 0 immediately that the wiring is correct. if it drops down matching the engine speed as the engine stops to 0 then its wired as a std car using the driver board to supply the rev counter feed.