It seems like there is a rash of these fuel pressure regulators going bad.
The '84 I just got had this exact problem.  It would start initially, but
then when it warmed up and you tried to restart it wouldn't.  The guy I
bought it from rigged up a switch to the fuel pump.  He would shut off the
pump when trying to restart and the van would start and then he would switch
the pump on and it would run.  So it seems pretty obvious that what was going
on was that the fuel pressure was too high and basically flooding the motor
when you tried to restart.
The other folks that were having this problem last week actually got so much
fuel in the cylinder that it caused a hydraulic lock (yikes!).
One thing that amazes me is that the fuel injectors are allowing the over
pressurized fuel to leak past them and into the motor.  I thought that when
these injectors were shut they wouldn't allow any fuel past them?  Or maybe
they aren't leaking past but just dumping a bunch of fuel when they do open
due to the higher pressure?  Any one have any ideas on this?

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
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