Camaro V8-305 5.0L VIN F FI (1985)
Chart C-5 Electronic Spark Control System Check
1.
Tests ESC to see if it can detect a knock and retard the timing.
2.
By disconnecting the ESC module, the ECM sees low voltage at terminal B7 and should retard timing. After approximately 4 seconds, "SERVICE
ENGINE SOON" light will come "ON" and Code 43 will be stored.
3.
Checks for proper voltage output (measured on A.C. scale) of knock sensor. Low or no voltage would indicate an open circuit to terminal "E" or
faulty sensor.
4.
Checks to see if constant retard is due to a faulty knock sensor or module, or if a false voltage signal is being transmitted on the wire from the
knock sensor by induction from an adjacent wire, such as a spark plug wire, ignition wire, etc. Reroute wires as necessary.
If engine knock is not present, and timing increases when knock sensor is disconnected, fault is an over sensitive knock sensor. Timing should not
normally increase.
