Can someone please tell me what the module in the distributor does? And what the Electronic Spark Control Circuit does that is behind my Mass Air Flow Burnoff Relay? Are they related? Thanks for any info.

 

The module has 6 pins.

1. Ground
2. Bypass, a 5v reference is on this line from the ECM, If disconnected, advance is disabled so you can set the initial timing.
3. Reference, this is the actual pickup amplified by the pickup coil in the distributer. It's a square wave signal. It's fed to the ECM.
4. EST, this line is the reference line with a modified duty cycle. Basically the ECM takes the reference signal and changes the duty cycle and feeds it back to the module. This is what makes the 'advance' possible.

Then in the 2 pin connector there's:

+ Which is just 12+ supplied by the IGN fuse used to power the module.
C Which is the "final" amplified and dwell corrected -12v square wave which is fed to the - coil connection.

There's also the 2 pickup coil connections inside the cap.

The knock retard module is just used to pull down a reference if knock is sensed. The ECM then starts to pull timing out of the module. They really arn't connected together (except in the ECM) and newer SD systems have this knock module built into the ECM itself.

Hope this answers your ?