My goal is to use and SD card to log a large amount of data from an inertial measurement system.

What I am trying to do should be simple, but it is now going on three weeks with no luck.

I have a T4.0 (not T4.1 with the builtin SD card) that I connected up an AdaFruit SD card breakout board.
I am using all the signals so that it can support SPI, 1 bit, or 4 bit SD mode.

I installed the Teensy-Duino package and can load and compile various test programs.

From another forum post I found a beta SD card library that is supposed to support the T4. I put it in the right spot and the Arduino IDE sees it.
I have tried various of the examples from that library with either no or limited success.

Could someone please post some rough instructions of how to get the environment setup properly and possibly an example program that just created and writes a file?
I am not sure if I am fighting a configuration problem, a hardware issue, or a software problem.