Low fuel pressure diagnostic on an 08 Ford F-250 5.4L

Diagnostic on a F-250 with low fuel pressure codes, kind of a redneck way to test it but it works.

[@enriquepina9417]

Thank you very much my man. I did the same process you did for diagnostic and sure enough I had a bad fuel pump. I took it to two mechanics and they could not find the problem. Me being a roofer and a little mechanically inclined saw your video and fixed it my self. Thank you again.

[@mannynieto21]

Also also with scan tool I am getting similar reading almost identical. I just have not replaced the fuel rail pressure sensor.

[@AP-xq3jm]

Thanks, very informative short and sweet to the point video. I have an 08 work truck with the same issue. Mine seems to run fine until it warms up and then it will only idle. If you push the gas pedal it does not respond but it will idle fine.

[@bulldogsautomotiveadventur4387]

That sounds like an electric throttle problem, if it has absolutely zero throttle response I would check there.

[@AP-xq3jm]

@@bulldogsautomotiveadventur4387 That's what I thought but if it sit for a few minutes it will run fine again for a few miles. I'm really thinking the ECU is bad. I need to find a wiring diagram, I gonna buy a manual today. I like your trick with the wire terminals. I'm an aircraft mechanic I have tools to troubleshoot and repair any big jet but not much for cars. My motto is, "If the car mechanics don't start working on jets I won't work on cars"! Lol. But the older gentleman who owns the truck can't really afford to put it in the shop. Thanks for guys like you making great videos.

[@marandavaughan8792]

Thank you! Subscribed

[@johnjohn-xo5gl]

Hey im having this same issue with the fuel pressure in my crown vic. I did the same test and replaced the pump and filter and it still drops to like 27 psi.... regulator and driver seem to be working properly.. any ideas?

[@bulldogsautomotiveadventur4387]

If it’s this style with only one fuel line then doing this bypass test should max out fuel pressure and not stumble while driving, if it still does then it’s supply. I’ve seen volume issues cause pressure drops also while under load.

[@johnjohn-xo5gl]

@Bulldog's Automotive Adventures that's my thought exactly, I'm running lean on both banks. Before I changed the pump I pumped out about 6 gallons of fuel up at the fitting at the fuel rail in just a couple mins of cycling the key. Haven't hooked up a mech Guage to it yet but could the fuel rail possibly be an issue? BTW thank you for a response

[@bulldogsautomotiveadventur4387]

@@johnjohn-xo5gl I would be more worried about a skewed sensor, need to hook up a mechanical gauge and compare it to the sensor…I wouldn’t rule out a bad pump even though it’s new also.

[@johnjohn-xo5gl]

@Bulldog's Automotive Adventures I've thought of it being a under performing pump but the car is acting exactly the same as my 280k mile pump (original) 42 ish psi at idle and down to 27ish under load. Will be testing fuel pressure tomorrow

[@chriswood4510]

Thanks, did the sender, fuel pump and sensor with no success…

[@bulldogsautomotiveadventur4387]

I’m very picky on which brand of fuel pump we use, I’ve had a few come in with a brand new pump that was just as bad as the one they replaced.

[@chriswood4510]

Oh yea? It was a cheap rock auto pump. Do you think replacing the fuel rail it’s self would be worth a try?

[@bulldogsautomotiveadventur4387]

@@chriswood4510 no, I’ve never had to go that deep

[@chriswood4510]

Ok thanks I’ll send her off to a professional! 😂I tried my best

[@bulldogsautomotiveadventur4387]

@@chriswood4510 things are getting way too expensive and complicated to guess anymore, I also see so many bad brand new parts I just don't trust anything new.

[@realhelper]

What's the cost for replacing the Fuel Pump on that truck?

[@bulldogsautomotiveadventur4387]

I don’t remember, been quite a while ago

[@bulldogsautomotiveadventur4387]

That job was about $1000 total, over half was the pump assembly, rest was labor, diagnostic, filter replacement, etc.