intermitent hot start problem

[richard bies]

> I have been fighting a hot start problem on with my '87 5Ktq (approaching
> 200K miles) for about 6 months....
>
The most difficult fault I ever found was a thermal discontinuity in the
pick-up coil of a pre-Hall distributor in a '79 5000.  Much as you
describe -- cool, everything seemed fine -- one had to catch the
distributor warm to detect anything wrong -- and once started it would
run. Finally, I carried a multi-meter with me and measured the resistance
across this coil in the failure mode -- no continuity -- then measured
again in a few hours when it would start -- continuity.  It took months to
get to that point.  (Odd oscilliscope results pointed suspicion toward
this coil.)  Aparently there was just enough active coil to trigger a weak
spark and keep the motor running, but not a strong enough spark to start.

r.m.bies