Knock Sensor: Testing and Inspection

Chart C-4C - EST Performance Check:

Wiring Diagram for Chart C-4C - EST Performance Check:

CHART C-4C - EST PERFORMANCE CHECK

Test Description:

1. Grounding the "test" terminal causes the system to go to a fixed spark advance which should be different from that obtained with EST operating.

Engine is run at fast idle to get more spark advance. Usually the change is enough so it can be heard in RPM change. If so, it is not necessary to check timing.


2. The check in drive is made because some engines will not have EST operating in P/N.


3. Checks to see if fault is in MAP/VAC system.