I have a fair amount o
I have a fair amount of knowledge and experience with the BB ignition systems...and can provide you with a pin-out diagram for the spark box.
JRVs test for the hall-effect unit is sufficient enough to determine if it's working properly. With the distributor unplugged from the harness, you should perform the same test to verify yours. Also, veify that this signal exists at the spark box connector (with the box unplugged.)
The hall effect pick-up output, in itself, is not enough of a signal to trigger a tachometer response...as the spark box provides amplification of the trigger pulse. Hense, no tach movement on cranking doesn't point to a fault.
True, the pick-up units are not available seperately, though some distibutors have a spare mounted on them that is not used...and can be swaped with a suspected bad one.
Basically, there are four tests that need to be done.
1- Verify voltage at the spark box, using the box itself as the reference ground. If the spark box is isolated from the chassis ground, and the box itself is not grounded properly...the ignition system will not work reliably.
2-Verify voltage at the coil on cranking. This test may be non-conclusive if the box is not receiving a signal from the hall-effect pickup.
3-Off car testing of the ignition coil
4-Verify pulse, waveform, etc. from hall-effect unit.
If there's voltage at the spark box, and it's receiving a pulse from the hall-effect unit...and the coil and coil wire test good, the problem points back to the box itself.
One thing that I have seen on numerous occasions is the wire spades have pushed out of the connectors between the spark box and the engine harness. A light tug on the wires (on the chassis side of the harness) will verify the solidness of the connections.
Please let me know if you need the wiring diagram/pin-out...and I'll dig it up for you.