With a no start condition, should fuel still flow through the fuel pressure regulator, or is there a lack of vacuum that keeps the pressure regulator closed? I have fuel pressure to the fuel rail, but nothing flowing beyond the regulator.If the regulator is blocked, should there be excess pressure and therefore excess fuel and wet sparkplugs? No excess fuel in cylinders after several attempts to start. I can hear fuel pump run. Could the pressure be to low?

85s dont have a radio suppressor. Maybe bad Hall sensor.

If you have pressure to the rail and you are also getting spark, you might try pulling an injector and see if it is shooting fuel. If it isn't, it probably isn't getting electrical impulses which may be caused by a bad Radio Suppression Relay (if they were used in 1985). The later model 740's had the RS relay mounted to the front of the coolant overflow bottle, and it generally responds well to resoldering.

Harley is correct. You may be on the wrong track with fuel. Why did you suspect fuel problem??? Residual pressure is normal with engine stopped. If pumps are running and you have fuel pressure engine will run. You will only see fuel going back to tank when pumps are running and fuel pressure is elevated some. Pumps do not start until engine is cranked and or running. The vacume line merely boosts pressure a bit during periods of high vacume which equates to heavy engine load. Car will start and even run with that vacume line off.
Check for spark first if you have not ready.
--
David Hunter

make sure you have spark.