How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Steve S Your Own Question
Steve S
Steve S, Ford Technician
Category: Ford
Satisfied Customers: 1866
Experience:  10 years in Ford Dealership, Certified in: Auto Trans, Diesel Engines, Climate Control, Electrical D
Type Your Ford Question Here...
Steve S is online now
A new question is answered every 9 seconds

Ford F550: I have a 2008 F550 6.4 my fuel pump went out so

This answer was rated:

I have a 2008 F550 6.4 my fuel pump went out so I changed it. the truck want start my codes are p0087 and p2291. i changed the oil and filter my p2291 went away, but i still have p0087. KOEO my fuel pressure is up and down 30-40 psi. shouldnt it be 0 thats what my desired psi is? when I spin it over my desired psi is 4000-4500 psi and my fuel psi dosent get above 900 psi i bleed my low and high side like alldata said
Hello there. Did you change the fuel pump on the frame rail or under the turbos? How did you pinpoint that the pump was bad? Thanks Steve
Customer: replied 4 years ago.

The one on the frame. I cut it off and it would not start I took the fuel filter under the hood out and turned the key on it wasnt filling up. i got under it and had fire going to one side of the pump with key on and ground on the other but the pump wasnt running.

That pump should only turn on for a few second when you first cycle the key to the on position. Does out with the new pump? Don't turn the key to the craning position but just to "on" and see of pump kicks on for a couple seconds. Steve
Customer: replied 4 years ago.

I guess i should have explaned it that way but thats what it does comes on when you first turn the key on for a few seconds than cuts off the old pump wasnt coming on at all and I had fire going to it. i had another guy cycling the key when i was checking it

Ok so after you replaced this pump how long did you try to start the truck?
Customer: replied 4 years ago.

I spun it around 30-40 seconds at a time wait a few minutes and do it again over and over. my fuel housing has fuel i got fuel at my service port

Ok. The choose PO 087 indicates low fuel pressure in the high pressure fuel system. This code is most commonly caused by the HIGH pressure fuel pump located under the turbos. And the code 2291 is am indication of low pressure in this system also., this is where I would be headed with diagnosis. This pump needs to create 1000s of pounds of pressure to operate and the pumps do fail frequently. Steve
Customer: replied 4 years ago.

ok. but whats causeing my fuel pressure not to fall to 0 psi when my desired psi is 0

You have two valves that are part of the fuel pump. These are the volume and pressure control valves. These are what fails then they can't control pressure and volume add the pcm would like. Steve
Steve S and 7 other Ford Specialists are ready to help you