Electronic Spark Timing (EST) Advance System
- A malfunction in the EST circuit should set a related trouble code. Start engine and warm to operating temperature. On vehicles equipped with a manual transmission, increase engine speed to about 2000 RPM. On vehicle equipped with an automatic transmission, slightly increase idle speed.
- On all vehicles, ground "test" terminal "B" of ALDL. A noticeable change in engine speed should occur. If no change occurs, see DIAGNOSTIC CIRCUIT CHECK in BASIC TESTING article in this section.