Firebird V6-173 2.8L VIN L 2-bbl HP (1983)
Knock Sensor: Testing and Inspection
Chart C-5 Electronic Spark Control (ESC) Check (Turbo)
Fig. 042 - Chart C-5 Electronic Spark Control (ESC) Check
CHART C-5, ELECTRONIC SPARK CONTROL
If the timing is retarded at idle, it may be due to ESC operating. ESC should not operate unless a knock is present.
1.
This is the ESC functional check. Simulating an engine knock by tapping the engine block should normally cause an RPM drop (decrease timing).
If it doesn't drop, either the timing is not retarding or is retarded all the time.
2.
This should cause full retard by dropping the voltage at ECM term. "L." Retarded timing should cause an RPM drop.
3.
Normally, voltage should be .08V AC or higher for a good knock sensor circuit.
