Crank, no start. Starts briefly on ether, then dies. P0191 on the reader.
Everything that has been replaced:
-Fuel Pump
-Fuel Filter
-Fuel Rail Pressure Sensor
-Fuel Pump Driver Module
-Grounding wire on frame
-Relays and Fuses related to fuel system


​​​​​​I had a mechanic(although, not one I particularly trust) with a high-end code reader do a full diagnostic. He said fuel pressure was fine, and said the pump was infact turning on. He told me with 150% certainty that it was the pressure sensor, so I replaced it, and same issue.

I'm out of ideas.
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A capable scan tool will provide the desired and actual fuel pressures. If we did not get that info the diagnostic is faulty.

Also,,, check the wiring and tightness of the connections to the pressure sensor.
Incorrect info to the PCM is as bad as no info.

 

I would advise going to the dealer. While sometimes more expensive, throwing parts at an undiagnosed problem gets really expensive. I had similar problem with my 06 E150. After chasing the problem with parts, advice, and frustration I took it to the local Ford dealer. They found the problem (wiring harness with broken wire), repaired it, and I have had no further issues. Yes, it was an $800 repair (all labor), but now all is well!

 

I could be wrong,,,,but you are going to chase that wire down, huh,,it would be wise to get a diagram of where the wires to the pressure sensor come from so you don't create more problems working blindly..

 

I've never come close to doing anything with the wiring of any vehicle, but it seems that is all there is left to check, and I don't even know where to start or what tools I'll need lol. Back to YouTube I go, I suppose

 

A little multimeter using the ohms function could help.

If you are careful,,,,,,,,,,,,,,,,,, the wires on the sensor have particular colors.
If you carefully trace where they go,you might find the problem,,IF you gently tug on the particular wire a little at a time and if if feels like spaghetti , you found it.
The cost of having it repaired is concerning and we understand that, but sometimes the advice offered by dpboone could be the better way to go..

Doing this type work everyday is just another job, but if never done before , it can seem monumental.

If you do a good visual inspection, you might see where the harness or wires rub against something and sometimes that provides a clue where to spend more time checking.. If you are not comfortable doing this type work, by all means, consider having a good shop tackle it.

 

The fuel rail pressure sensor also includes the fuel rail temperature sensor (both are part of the same component). Thus they share a signal power supply (VREF) and signal "ground" (SIGRTN). I gather that your scanner guy saw no signal for fuel rail pressure to make him believe the sensor was bad. You should ask him to check now (with the new sensor) for signals for both fuel rail pressure and fuel rail temperature.

If the temperature is good, and the pressure isn't, then the problem is likely in the pressure signal wire. If both are bad you should investigate the wires for VREF & SIGRTN.

btw, The above assumes 4.6 or 5.4L (they're both the same for this circuit).

 

i had same problem. Gave up and went to dealer. They found melted wire in wiring harness. $800 later they repaired the harness and no further problems.

 

Any good diagnosis begins with a good visual inspection and many times a problem is found before getting really involved.
Also, sometimes we aggravate the problem if we move things without watching closely what we move.