1992 F250 7.5 Liter Fuel Delivery Problem
 

1992 F250 XLT Lariat 7.5 Liter Gas -
Used but new to me. Ran well few days then would not start, spark but no fuel.
Fuel pump fuse, relay and inertia switch all checked good. No audible sound from rear fuel tank fuel pump, dropped rear tank and found electrical connection to fuel pump not locked in place, loose and not making contact with fuel pump connector. Locking tabs on electrical connector were broken so replaced with new connector. Verified voltage at connector and reconnected to fuel pump.
Decided to replace fuel filter, connection on engine side of filter was hard to get off and internal O-ring broke up when removed. Note: I suspect part of the O-ring may have stayed behind within the fuel. Line.
Installed new fuel line connector on the fuel line and reconnected.
Now, engine no start and no pressure at test port (Schrader valve) on fuel injector rail. I do have pressure on engine side of fuel filter.
I suspect blockage in fuel line, maybe piece of O-ring. Question is what do I do to get it out short of replacing fuel lines, which are not very visible. Is it possible to disconnect fuel line on engine side of fuel filter and apply low pressure to Schrader valve on fuel injector rail to blow out tubing?

I'm and aircraft mechanic that stumbles through automotive repairs.
Any help/advice appreciated.

Note: Front fuel tank leaks and is not used.

It can be a PIA to disconnect the fuel lines in different places to verify passage is clear. Can't say for sure , but possibly a piece of something is stuck in the pressure regulator on the fuel rail holding it open so no pressure can be built up. . You know what you need to do and we try everything to make sure the lines are clear , If compressed air is available , might attach a cloth or something to the line coming off the filter going to the press reg to catch anything and blow it back. If you see something ,you know you got it. What do you think?

Those little tan O rings are usually available from Ford.

I think you are on the right track. Thanks for pointing out the fuel pressure regulator which I totally overlooked yesterday in my frustration of trying to trace the fuel line from the filter to the engine. Getting the regulator removed looks like a PIA. I'll post my findings.