Won't start pointed uphill

[komual]

Out of deep lurk mode with a question... 1993 W350... replaced the transfer pump that mounts on the block about 6 months ago when the symptoms started, and it was better for a while. Now it's back, and worse. If the nose is pointed uphill at all, she'll crank, but not fire til leveled or pointed downhill. I'm thinking the return line must be letting air in and "unpriming" the system, and need replaced? Clues and troubleshooting tips appreciated. I haven't been around for a while 'cause she's been just running fine for quite a while. Sad note: pulling the last load from my old house to the new house Friday I got t-boned in traffic... took out the front half of the bed, and the extra cab section of the cab. Rats! Alan, waiting for insurance adjustors...

 

[fox]

Are you getting any signs of a leak?

On my 95, the return line was leaking, first just letting air in, then fuel out when it got worse.

I am not familar with the 93 return line.

 

[komual]

No visible leaks, but as you said, it may just be air at this point. Is this a drop the tank job?

 

[fox]

I would suggest that you follow the lines from the tank forward to the engine. The bigger line is the feed and the smaller is the return. Check it all the way to the pump/injectors and make sure it is tight and dry.