Format a Standard SD card, 2GB or less with SdFotmatter https://www.sdcard.org/downloads/formatter_3/.
Change line 187 of the fat16info.pde example to:
if (!card.init(0, 4)) {
This selects full SPI speed and pin 4 as chipselect.
Run the fat16info example and post the output.
Post your the init code for Fat16 and any output.