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A. Penland
A. Penland, Ford Senior Master Technician, ASE
Category: Ford
Satisfied Customers: 6212
Experience:  ASE Master Certified, ASE Advanced Gasoline Engine Performance
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My 2010 f150 5.4L v8 wont start. With no previous warning

Customer Question

my 2010 f150 5.4L v8 wont start. With no previous warning signs the engine cut completely out and will not start. I have spark, and good battery.
JA: Have you checked the battery, particularly the terminal connections? Are they corroded?
Customer: no, brand new battery. replaced it yesterday. strong turning of the starter motor
JA: Are you fixing your F150 yourself? What have you tried so far?
Customer: I am. I tested for spark and there was spark.
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 1 month ago.
Category: Ford
Expert:  A. Penland replied 1 month ago.

Check fuse 27 in the engine bay fuse box. It is the fuel pump fuse and there is a known problem with it shorting out and melting. Below is a TSB for Ford technicians to fix the problem.

Customer: replied 1 month ago.
I have also tested for fuel. No fuel is getting to the fuel rail at top of engine. I then disconnected a line just outside the fuel tank and there was also no flow. Could this be filter or pump? Or something electronic? how can i diagnose from here?
Expert:  A. Penland replied 1 month ago.

Check fuse 27 in the engine bay fuse box. It is for the fuel pump. Click on the link for the TSB.

Customer: replied 1 month ago.
Its not the fuse. Just checked it.
Expert:  A. Penland replied 1 month ago.

Does the fuse look burnt or melted?
Look in the socket where the fuse inserts and make sure the wires are not melted.

Customer: replied 1 month ago.
fuse looks perfect. tested it with meter. all is well. socket looks good also
Expert:  A. Penland replied 1 month ago.

In the engine bay fuse box and remove the fuel pump relay. Then check for power on pin #3 of the relay socket when the key is turned on. See the diagram below.

Customer: replied 1 month ago.
its looking like there is no power. supposing i tested it right. I tested other relay sockets and i got 12 volts coming from pin 3 socket. but nothing from the fuel pump socket. even with key turned on
Expert:  A. Penland replied 1 month ago.

That pin gets power from fuse #27. Follow the TSB I posted to repair the problem. The fuse is getting power but is not sending the power to the relay. The TSB is placing a larger relay and larger wiring pins to handle the current load of the fuel pump.

Customer: replied 1 month ago.
I am not getting any of the indicated codes that it lists in the TSB. Do they necessarily need to be there?
Expert:  A. Penland replied 1 month ago.

Not really.

Customer: replied 1 month ago.
I lied to you. I made an error while testing the relay socket for the fuel pump. There actually is power coming through. And the fuel pump relay is also working fine. I put the fuel pump relay into the starter socket and it worked to spin the starter motor.
Expert:  A. Penland replied 1 month ago.

You are getting power on pin #3 of the fuel pump relay with it removed and the key turned on?

Customer: replied 1 month ago.
Expert:  A. Penland replied 1 month ago.

Next I will need you to go to the FPDM (fuel pump driver module) located on the frame rail above the spare tire on the drivers side and check for power on the VIOLET/LIGHT GREEN wire at the FPDM with the relay installed and the FPDM unplugged. It should be pin #1 in the diagram below.

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