Can SD chip be put into "diagnostic" mode??

[Flyin Brian]

I recently was trying to verify my timing and followed the instructions to put the car into diagnostic mode by jumping pins A and B on the ALDL connector to fix the timing at 15 degrees. The check engine light flashes when I jump the pins but the timing does not change. It just stays around 28 degrees at idle. Is the SD chip not designed to do this??

 

[Eric Stage I]

Yes it works. Your timing will be commanded to 15*, but Powerlogger only displays what's commanded from the timing table, not diagnostic timing.

 

[Flyin Brian]

Thanks Eric.
The engine sound changed when I put the jumper in but I was looking at the timing on the Powerlogger which did not change.
Makes sense now.