Thanks, Pete (and Joel and Rico) for responding and clarifying some
of this electrical stuff.  Maybe it's not so complicated after all.
And I will definitely check that Hall sender connection.

I realize that I wasn't specific in my original post regarding the 86
terminal of the power supply relay.  I don't know if it matters but I
also tested it at the socket with the relay removed and did not get
any voltage that way either.  I'll try to run that down this
afternoon (now that I'm such an electrical diagnostic expert ;).

Marc

>[snip]
>
>
>The hall sensor can kill your van stone-dead. Our old '81 airsucker had
>this problem. There's a really dodgy connector on the outside of the
>distributor. The wires from this leading inside the distributor to the
>hall sensor get flexed as the connector jiggles around. These wires are
>really thin & can either break or short out to ground. My van would
>be cruising down the freeway & just suddenly die. I'd get out & jiggle
>the connector while Lynda cranked it over. *Vrooom*. Eventually, I
>re-wired the sensor & replaced the outside connector. No problems ever
>again.
>

[snip]

>Pete C
>
>--
>Peter Cassidy,                   pcassidy@apple.com
>Sr. Test Dev. Engineer             +353-21-284316
>WW Operations
>Apple, Cork.