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Hello everyone, been a while since I’ve posted here. I have some diagnostics I need help with. I strongly believe it is fuel related. Details below.
2005 F-150 XLT 5.4L 4x4
While driving down the road last week the truck stalled. Waited a few minutes and fired it back up and headed back home. On my way home the truck died about 3-4 more times but always started back up and drove another mile or so before dying again. Once I got home I let it sit over night since it was dark, went out the next morning and it wouldn’t start without starter fluid, only to die a second later. Pulled the codes and got a PO191.That signals a fuel issue. Since then I have replaced:
All to no avail. What else can I try to fix this problem? I was advised to maybe replace the fuel pump relay but I cannot find a location on my fuse diagram or online and in fact some sites say the 05 doesn’t have a fuel pump relay. I’m at a loss. Any and all help would be greatly appreciated! Thank you!
Last edited by grahamjt04; Jan 5, 2023 at 12:47 PM.
You need to see if this is fuel related or electrical. Have you tested your fuel pressure while driving?
I have not tested fuel pressure. Mostly because I cannot get the truck to start anymore without hitting it with starter fluid. Once it starts it almost immediately dies so I can’t drive it to test.
I have not tested fuel pressure. Mostly because I cannot get the truck to start anymore without hitting it with starter fluid. Once it starts it almost immediately dies so I can’t drive it to test.
Right, but baseline you need to see if you have fuel pressure. If you don’t, then check power to the relay, then power to the pump with the key on. If you have all that, you’ve got a delivery issue.
If you’ve already replaced the FPDM under the spare tire, that’s the most common point of failure on the fuel system and can be eliminated.
Right, but baseline you need to see if you have fuel pressure. If you don’t, then check power to the relay, then power to the pump with the key on. If you have all that, you’ve got a delivery issue.
If you’ve already replaced the FPDM under the spare tire, that’s the most common point of failure on the fuel system and can be eliminated.
How do I test fuel pressure if the truck won’t run? Is there a way to do it?
Also, how can I check the relay? I cannot located the fuel pump relay. Can’t find anything on line either.
How do I test fuel pressure if the truck won’t run? Is there a way to do it?
Also, how can I check the relay? I cannot located the fuel pump relay. Can’t find anything on line either.
IF you have a OBD2 scanner that reads live values you should be able to check the fuel rail pressure with it.
As for the fuel relay im pretty sure there is one in the fuse box.
The best way to check fuel pump circuit is to look for voltage on the fuel pump supply wire at the plug for the FPDM connector. If you have voltage there then that means the inertia switch, relay,everything upstream all the way to the fuse is likey good.
The thing I would check if it's not a fuel supply issue is the crank position sensor and wiring.
How do I test fuel pressure if the truck won’t run? Is there a way to do it?
Also, how can I check the relay? I cannot located the fuel pump relay. Can’t find anything on line either.
Rent a fuel pressure test kit from Autozone. See if you have pressure on key “on” cycle, then see what your pressure is during cranking. You don’t need it to fire off in order to make sure your pump is sending fuel thru the rail.
When you first turn the key to the ON position can you hear the fuel pump run for a few seconds? I doubt this is your issue but if you did not hear the fuel pump run then you should check and make sure the inertia switch is reset and has voltage in and out. Inertia switch is located near the Central Junction Box (Fuse Box), located behind passenger's kick panel.
As Jimboy asked, do you hear the fuel pump run briefly then quit when you turn the key to the Run position? If so that eliminates the Fuel Pump Relay, Fuel Shutoff Switch, and Fuel Pump Driver Module as the problem.
If it runs, we really need to know the fuel rail pressure. Does your OBD tool show this? If not, maybe someone you know can help out.
If not and you want to check the Fuel Pump Relay, it’s Relay #303. It’s not shown on the black cover over the fuses/relays box. But it's the one that’s located directly below Relay 02 shown on the cover (photo below).
The Inertia Fuel Shutoff Switch is shown in the 2004 Ford F150 Wiring Diagrams manual as located near the fuse box. It’s got two wires. One is dark green with a yellow stripe and the other is orange with a black stripe.
As far as I know the fuel pump relay is soldered on the back side of the fuse box . You more or less have to get a new fuse box or a junk yard one . There are tests to prove its okay . There are connections under the truck driver side going to the fpdm . You need to get a test light going to prove where your are losing power to the pump or not .
Fuel pressure should show on fuel rail with key on . Torque pro will read it .
2005 Fuel Issue
