If you have ready access to a spare then swap the ECU but keep an open
mind. A simple wiring fault could be involved. If you don't hear the
fuel pump when you turn the key back on after it dies you can forget
worrying about the hall unit of the distributor.

There is a known failure point in the 86+ dash fuse/relay panel where
the wire connects for the ignition on signal that runs back to the
engine compartment. Pin D15 of the panel gets cooked over time and then
doesn't always make a reliable connection. If this is your problem no
amount of parts swapping in the engine compartment is going to fix it.

 From the ignition switch a black "ignition on" wire goes to the dash
fuse/relay panel and then leaves again on pin D15. From there it is part
of the main wiring bundle that heads back to the engine compartment
wiring box. The black wire continues on to the ignition coil to power
it, and then branches off to power up the ECU relay and enable the fuel
pump relay.

For testing purposes you can run a wire from the alternator power stud
to the ignition coil where the black wire attaches. There should be a
free male spade available there next to the black wire that comes from
the ignition switch. This will immediately power on the coil and ECU
relay so the key switch won't be able to turn the system on or off while
the test jumper wire is in place. I would put a fuse holder in the
jumper wire at the alternator end. Then use the fuse to turn the power
on and off as needed. I'd use no more than a 10 amp.

Mark

OlRivrRat wrote:
>                 Hey All Here's one for ya
>
>         A NonMech' good friend has an '89 4spd2wd H2OBxr with 217000mis
> ~ It
> will start just fine & idle & run just fine for a Random period of
>
> time then instantly shutdown as if the key was turned off ~ then in
> most cases it will start right back up again. On the occasions that it
> doesn't
>
> start right back up I can tell that the FuelPump is not doing the
> PreStartRun but then after a few tries or a short wait does come on
> when Key is
>
> turned to Start & will then FireUp&Run.