Mine is a 1990, and I basically have the same problem. My van won't start
even cold. Today it didn,t satart in the morning, but it worked great the
most of the day. What I was doing in the morning was to connect my battery
charger for about 30 mins. and it would turn, no problem. Then I bought the
relay kit from the Bus Depot, happiness didn't last. Replaced the battery
about three times before that and not long ago, replaced the ignition
switch. I traced the problem to a voltage drop at the starter. I wired the
relay kit in such a manner that I can jump-start the starter directly using
the alternator wire. Just turn the ignition switch, and if nothing happens,
go to the rear, open the engine compartment and with the wire from the
relay, touch the alternator's cable coming from the battery. It cranks very
fast, starts right up. Been planing to pull the starter for a while, getting
tired and embarrased.

Hector