Hey guys, meet Barb, shes a 85 f250 with the 6.9 idi. I bought her off some guy who had her sitting in his field for the last 10+ years.

I put 2 tanks through her, she ran great no issues, starts right up every time.

But I was driving the other day and all of a sudden she lost power, no bang or boom, just no power.

I can put my foot to the floor and it only revs up to like 800 rpm.

Replaced-Lift Pump (no fix)
Replaced-Return lines (no fix)
Bypassed-Gas Tank and Fuel Seperator (no fix)

No smoke when pump is held full open, not any studdering, just doesnt rev or idle the same.

Heres a video of it

Let me know what you think. Im new to diesels and pretty much stumped.

 

Is that at the pump or just pushing the pedal?

 

it almost looks like your injector pump is dead.

 

Lets see.
First off, put a cheap mechanical pressure gauge after the fuel filter, before the IP. Check that you are getting fuel to the IP.

You might even just be able to run it, then depress the schraeder with it running. If you get plenty of fuel out, you are fine. No fuel or very very little, you might have a blockage problem.

If you do have good fuel *to* the IP, something's stuck inside. I'd do the fuel-filter fill with ATF trick, then go from there.

If that doesn't do it, it's probably worth removing the top off the IP(watch videos first), and verifying that the governor assembly/metering valve is freely moving. It might be stuck.

edit:
One more 'fuel starvation' issue solution:
There's a small screen at the IP inlet, just after the hard fuel supply line attaches to the IP. You'll want to read a guide or check videos, but you can pull off the nose cone of the IP back there and make sure the screen isn't plugged.

The truck sure sounds like it's having trouble getting fuel, but that the pumping element in the IP is fine.