Hi folks,
i need your opinion on something that happened to me last week.
I went out for some errands with my 1997 F250 XLT 7700lb package (7 lug) 4x2 and it was all going good as usual, then after a turn i gave gas to join the ongoing traffic and the truck stalled, it did the opposit of giving the power i asked.

So my reaction was to remove the foot from the pedal and the truck idled just fine. So i pulled over in a parking lot and the truck was idling normal.
Since i was not too far from home i decided to proceed not revving like crazy.
So i went back on the road and it was driving ok, another turn, i accelerate (road was on a hill) and the truck died.

It didn't start ever since.

Now that you know what happened before it died i tried to connect several scanners and none of them work, there's no DLC connection.
I checked all the fuses (both in the engine bay and under the dash).

When i turn the key the fuel pump relay doesn't come on. I tried to bypass the relay and i have fuel pressure. So i thought i had a bad computer.
I bought a used computer from a junk yard, it seemed like it wanted to start a little bit but nothing, after 3 or 4 tries now i'm back to square 1, truck cranks but doesn't start.

I found a post on google where a guy was having the same problem and a technician asked to check the power wires on the pcm.
Well i get power and ground on all the wires.

What else could i look at?
Thanks

 

My bet would be fuel pump. Grab a piece of 2X4 and whack the tank while trying to start it. If it starts, you need a fuel pump.

I had the same thing happen a couple years ago. Replaced the fuel pump, and no issues since.

One tip, don't go with the cheapest pump. You'll pay for it in the end...

 

Fuel pump works, i have pressure when i bypass the relay.
I still have no priming from the PCM and no DLC connection.

 

i also forgot to mention that doesn't matter how much starting fluid i spray, it won't start.

 

I was finally able to start the truck.

I will describe my solution for whoever happens to have my same problem, because it is terribly frustrating.
My suggestion, before trying this, is always to run a diagnosis with a DTC scanner becsuse a help from the computer can be HUGE.
In my case i had no communication whatsoever.

I was browsing the internet looking for somebody with the same problem.
I found this video by Scotty Kilmer, where he points out a few suggestions. One of those were to disconnect the sensors one by one untill there is a communication with the scanner.
I thought it was totally dumb but... hey, whatever.

So i started with the purge solenoid, nothing. Right next to it there was the DPFE, i disconnected the connector and BINGO, truck communicated again thru the DLC and fired right up.

I replaced this DPFE sensor last December after a failure of the original one. I bought it on ebay, cheapest one. It only lasted 4 months... I don't know if it's a coincidence or they all suck.
However this would have saved me the cost of a new computer. At least now i have a spare in case something happens.

I hope this helps somebody out there.