Greetings, Fellow F150 Enthusiasts!

Truck quit on me, seemed like out of gas, with 1/2 tank. Towed home and started troubleshooting -

1. Fuel pressure indicated 18psi
2. Replaced fuel pump
3. Started, run rough, fuel pressure indicated 22psi
4. Engine stumbled, then died
5. Cranked, no start; fuel pressure 0 PSI
6. Verified pump relay function via DTC FB ground
7. Verified pump operation by disconnecting line from filter
8. Disconnected fuel line from filter to fuel rail, used shop air to verify clear
9. With fuel pressure gauge in place, used shop air to pressurize fuel rail - 0 PSI
10. Removed fuel pressure regulator, using shop air verified fuel rail clear
11. Replaced fuel pressure regulator
12. Crank, no start, via DTC FB ground pump relay not functioning
13. Apply alternate power source to fuel pump, bypassing wiring harness, verified function
14. With fuel pump running on alternate power, crank and immediate start
15. After engine warmup, run from from idle to 3800 rpm; no issues, shut down
16. Remove fuel pump alternate power source
17. Replace fuel pump relay
18. Crank, immediate start, dies after 8 seconds, crank - no joy

So, with all this done, it seems the PCM is operational but the fuel pump circuit is not energized. Next step is to shunt inertia fuel cutoff.

Apart from this, any recommendations?

 

If fuel pressure is low, step 2 should have been to measure voltage at the pump. If that's not the same as battery voltage, trace the circuit to find the high resistance, and repair it. Study this:

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Thanks for the assist, Steve83.

In looking at the diagram

1. pump harness call-out diagram states pump power wire to be orange, with brown/white ground
2. fuel pump switch indicates brown/white power and orange at pump to be ground
3. only one tank - rear, so assume there is jumper in place of tank switch

Battery died, so waiting to charge to conduct voltage test.

 

Steve83 -

Thank you very much for the diagram. Reversed polarity of pump wiring and started right up! Doesn't make sense why the connector diagram would differ, but what the heck - it worked!

Many thanks and best regards,

Peter

 

I have a 1988 4.9 liter 4speed.
Replaced the fuel pump and filter after no start. Im running on the saddle tank, not the rear. I have 60psi at the schrader valve on the fuel rail. it idles well, and drives pretty well, but when I accelerate while driving and shifting up in gears it surges quite often.
I am thinking it might be the fuel pressure regulator. At first I thought it was just clogged injectors from bad gas from years of sitting, but after a fresh fillup of 93 and seafoam spray&liquid, it still has the same effect.

Any on my next step of diagnosis? I plan to take off the manifold and replace the regulator, but I dont want to do that unless I am sure of the problem.
How can i test that i have proper vacuum to the regulator?
I ripped out all the smog equipment recently and i think i might have disconnected some of the vacuum lines..

 

It's not a saddle tank - only GM used those for a few years. They're OUTside the frame rails. You're using the FRONT tank. No, the FPR can't cause surging, and you don't have to remove the plenum to change it. The FPR uses full manifold vacuum - if you have a good hose from the tree to the FPR, it has the correct vacuum. But if there's gas in that hose, the FPR is ruptured.

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Ripping $#!+ out is probably what caused your truck's problems. You should fix it back the way Ford built it - it ran correctly that way, so it can again.