Side Effects of the PocketLOGGER cable:
The cable for PocketLOGGER for DSM's has a side effect in that when it is plugged in, the ABS is disabled. This is due to the fact that the diagnostic pin for the ABS computer is tied to the ECU's diagnostic pin. It is impossible to put one in diagnostic mode without putting the other one into diagnostic mode as well. This is not an issue with 91 GVR-4s.
The only way around this is to disconnect the ABS computer from the diagnostic line. Here are some links to more information on doing this.
Setting the timing:
To set the timing in a DSM, an underhood connector needs to be shorted. The problem arises when you try to set the timing when the PocketLOGGER cable is connected. Having both the PocketLOGGER cable plugged in and the timing connector shorted, you are really telling the ECU that you want to set the idle. If you are trying to set base timing, be sure to disconnect the PocketLOGGER cable.