Truck starts and dies in seconds

[chundering pigiron]

Hey,
I know i can get some help here... Ive got an 86 6.9 4x4. Ive owned it for years , actually ive had several..But i sold this one some time ago and recently got it back. The guy i sold it to played with the injector pump timing and then set it back to factory apparently. Ive noticed a tiny bit of fuel puddling under th intake and when i fired it up it runs for about 3 secs and dies. I notice its a bit gutless now too. My freind has a 7.3 idi and it does the same thing, but if he parks it facing down hill on a good angle its fine. Both trucks are over night problems, and both have had the injector pump played with. Ive heard something about the return lines? Im not an invalid and can fix any part, but before i go mucking about i thought id ask the smart guys first..

[Scoobywagon]

Start by inspecting your fuel return lines for cracking. If it hasn't been done, you should also change the fuel filter. When you do that, pour the fuel out of the old filter into a jar or something so that you can inspect the fuel. You're looking for either water or little chunks of red stuff. Water means you need to drain the fuel/water separator. Red chunks means fungus in the tanks that has likely started to foul up your fuel system. If the fuel return lines are cracked, spend the $80 and get the kit to replace the hose, fittings and clips. Purge the whole system and see what you get. If the behavior persists, then check fuel pressure at the fuel filter. You should get about 5 lbs with the engine running. If you do, then turn the engine off, wait a few seconds, then check the pressure again. It will likely have dropped just a bit. 3lbs is probably ok, but if you get 1lb or less, your lift pump may be toasty.

[Evel486]

Also check the front bottom of the injector pump for a leak (dentist mirror works good) The pump has a weep hole for bad driveshaft seals.