NCWrangler

I recently acquired a 1989 F150 with the 4.9 Inline six, auto trans and single fuel tank. It has been sitting and not started for 12 years. I oiled the cylinders and replaced spark plugs, I have drained all the old gas, replaced the rear pump assembly, removed and checked the inline rail pump, blew out all the fuel lines, replaced the filter and finally got the truck to fire for the first time in 12 years. However It will only run for about 5 seconds and then die. It will not start back until it sits for about 5 or 6 minutes and then it will do the same thing. Tested fuel pressure at the rail and it primes up to about 50 lbs after a couple tries. then holds 45 lbs when its running for the few seconds until it dies. After it dies or after I prime it during a no start the 50lbs of pressure will leak down to 0 in a matter of a few minutes. I would appreciate any help on where to check next

Steve83

That's a start, but that & much more needs to be in your signature as this caption explains:


(phone app link)Exactly how did you check it?Define "not start" - does the key not turn? Does the starter not engage? Be specific & descriptive.Start with this caption, but follow the link to the fuel reservoir album:


(phone app link)

NCWrangler

Steve83, Will definitely work on the signature and more specs for the truck, I did remove the inline pump and cleaned both openings with car cleaner and bench tested function with diesel fuel. It did pull diesel fuel out of a container and shot it several several feet so I felt like it was ok. I reinstalled it and it does prime for about 3 seconds when the switch is turned on.
The no start I am describing is when the engine will turn over but will not fire. It will fire up and run smoothly for about 5 seconds then fade out like fuel starvation. Then it will not fire again until it sits for about 5-10 minutes. REminds me of some type blockage or constriction that burns the available fuel but it takes a while for new fuel to reach the cylinders. However the fuel rails holds 50lbs when trying to start and when running so not sure how it could have a blockage. Thank you

NCWrangler

Oh, forgot to mention that I did open the fuel reservoir canister and cleaned it out. There was no filter inside and was fairly clean inside, then reassembled. Not sure if there is supposed to be a filter there or not.

Steve83

3 sec. is about 3x longer than it should be. Check this:


(phone app link)

The reservoir album explains how to tell if it should have a filter.