Test D8 - Octane Adjust

NOTE: Enter this test when directed here by Diagnosis By Symptom Test in QUICK TEST procedure.

Fig 1: Octane Adjust Circuit

NOTE: This test is intended to diagnose the following:

Harness circuits, VPWR and OCTANE ADJUST
Octane Adjust Shorting Bar connector

The purpose of the Octane Adjust Shorting Bar is to provide optimum spark advance for the fuel being used. If the vehicle engine detonates (spark knock), REMOVE the Octane Shorting Bar. This retards spark advance about 3 to 4 degrees. If the vehicle continues to detonate, use fuel with a higher octane rating.