Hey guys, been lurking for a while. This site has helped me with many many problems. Thanks to everyone here. Finally decided to post on this issue. I have a 1997 obd2 (yes confirmed) 7.5 gas f350 ex uhaul box truck I bought. Truck has 175k and is in great shape overall. Has sat for the last 8 or 9 years. It has fresh fuel in the system though it sat almost on empty that entire time. The truck has no fuel pressure at the rail test port. I cycled the key 5 times then depressed the stem in the test port and only a small weep of fuel. Not even enough to drip. I suspect the pump for obvious reasons but want to test back to the tank properly before diving in.

I have checked the fuel pump relay (#2 position) and bench tested confirmed good.

pulled the 20 amp fuse for the fuel pump (#16) and checked for continuity. Tests good

the truck starts on starting fluid so I know my problem is fuel. What I am curious about is diagnosing from the fuse box back to the pump. This truck has a single fuel tank so I do not have a selector switch. I cant seem to find any wiring diagrams for an obd2 460 cab and chassis with a single tank.

can anyone shed some light on wire colors and functions, or possible other causes in the wiring so I can test back to the tank and confirm my problem? I'm currently stranded 450 miles from home with this issue. Thanks in advance!

 

The most likely problem is a dead fuel pump, this is almost always the problem with a vehicle that is unused for an extended period. The next most likely cause is rodent damage to wiring.
It's also practically useless to ask about wiring colors as Ford changed them yearly and I don't know that there was even an consistency between manufacturing plants
The electrical connection at the fuel tank should be fairly easy to access and disconnect on this truck, with that done you should be able to measure for voltage when the pumps are engaged at cranking. Note the pumps are only engaged for 1 seond when the key is first turned to run, but run constantly when the stater is engaged.

 

Thanks conanski. Wasnt aware they changed the wiring colors so much. I am aware of power only being at the tank for a second when ignition is switched to run. Unfortunately for me I'm solo on this trip and have no one to crank the engine while I'm under the truck. I've already dropped the tank. Going to replace the pump and test that it works before lifting the tank back up in. Had to buy a jack at harbor freight to get it down and out of there. Going to siphon the fuel out so I can get it back in. Wish me luck