Hello, this is my first post, so bear with me. I’m working on my grandfathers 89 F-350 with the 7.5. That has sat for 10 years, I’ve replaced several things including; the map sensor, front fuel tank and pump, fuel injectors, ignition switch, eec relay, and battery. I let the cylinders soak in marvel mystery oil before I installed the front fuel pump and tank. I don’t have the rear plastic tank clean yet, so I just connected the old fuel pump up to keep the fuel from pouring on the ground when the front pump is turned on. When I started it up yesterday day, it ran great for a few seconds then died. I tried a few more times, same result. My question is, will not having the rear pump/tank cause some kind of pressure problem resulting in fuel not getting to my injectors?

 

Was the fuel tank selector switch last on the rear tank when the truck was parked? My guess is that the dual function reservoir ( on the the driver’s frame rail) is stuck drawing fuel from the rear tank so you cannot access that fuel in the front tank. That is was happened to me when I put my truck back on the road which had been parked about 9 years. It left me stranded on the highway with a full tank of gas I couldn’t access.

 

Thank you for your reply. My truck doesn’t have that reservoir on the Frame. I was certain it would, but mine doesn’t have that or the external pump. I know the front pump is working. I hear it, and I disconnected the fuel filter line to see if fuel was going thru ( it was). I haven’t put in a new fuel pressure regulator yet, or checked pressure to the rail. I’m not sure if that could shut me down like this.

 

Sounds like you have a 1990 truck and not a 1989.

 

What letter is in the 10th position of the VIN?

1989 is “K” ; 1990 is “L”