The distributor has nothing to do with the advance of the timing on your system. The pickup in the distributor sends a pulse-train to the Thick Film Ignition Module (TFIM). The TFIM sends that pulse train to the ECU. The ECU decides where the timing should be and sends a pulse-train back to the TFIM. The TFIM then switches the coil based on the pulse-train from the ECU.
If the PIP is unplugged, the TFIM reverts to the pulse-train coming from the pickup in the distributor, which is the base timing with no changes from the ECU.
Either the ECU is not sending a pulse-train out to the PIP, the wiring between ECU and TFIM is bad, or the TFIM is bad.
Check out this site
http://www.therangerstation.com/tech...iagnostic.html