Paul is 100% correct. The fuel pump(s) has a fuse link.

This is what your fuel system should look like:


Notice there is no high pressure frame rail fuel pump.....

 

When we finally got it running, and wonderfully at that, I unplugged the pump on the frame rail and it kept running for about 15 seconds.
I'll try to get some pix today.
Guessing this truck may have been assembled from junkyard parts but it sure runs great now.
No noise from front tank pump yet but that's another puzzle. Power? fusable link? broken wire? etc.
Really appreciate the advice and will try to stay on it.
Door jamb and registration says 1991 but I'll double check that too.
Maybe look for a frame number somewhere.

 

truck in question says 5-91 on door jamb and
vin# matches the one on the dash tag.
Let me go check the 92.
ok
the 1992 f150 says 7-92 and I'll go crawl under that one and see if it has a rail pump.
When, may I ask, did they go from 2 low press pumps and fuel diverter and hi press rail pump to
separate tank pumps with no diverter?

 

Ford stopped using the low pressure in-tank pump/frame rail high pressure pump setup after the 1989 model year. 1990 and newer trucks used an in-tank high pressure pump, or pumps if you have dual tanks. For whatever reason someone has most likely retro-fitted the older fuel system onto your 5-91 manufactured truck.

 

ok, confirmed.
the 1992 only has a fuel filter on the frame rail.

I now wonder how to check which (in tank) replacement pumps I got for the 1991 with the hi pressure pump. How do we tell from looking at the pumps?

Whatever they are, I should keep them as known working units but not sure what injection design they are for. I have an 89, 91 and 92 trucks so they may come in handy someday.

yupp. the 1991 has a pump in each tank, fuel diverter and hi press pump on the frame rail. Looks just like my ol' 1986 f 150.

also wish I knew where to look for the fuel pump fusable link(s).

Gonna hafta pay you guys back some how.
I read xrays, (26yrs) if that helps anyone.

 

I have worked on diagnostic imaging equipment for 29 years.

Glad to see a fellow "glow-in-the-dark" brother on the forum boards!