2003 4.6L f150 fuel problems

The only way to properly check the three electronic systems you indicate is with a live data analyzer. You can turn the key to the on position and check for voltage at the fuel pump. if none, begin checking backward. If the inertia switch has power to it, then begin checking for wire damage back to the pump.

thanks I will do that today, one more question what feeds power to the relays, PCM? Battery or other computer components? 2003 Ford 150 4.6L

Have you checked the relay in the fuse box to make sure it is good. To long to explain here, but there are videos out there on u-tube which will show you how with a multi-meter. Normally, you will have to jump from the battery power to the # 1 pin and negative to the number 2 pin.. If you hear a click, then the relay making the connection. then you'll have to check the other pins to make sure the connection is good. Without a wiring diagram for your vehicle I am guessing, but I'd say power is supplied to the relay via the PCM once the key is switched to on.

Thanks, I just replace both relays already, I disconnected harness at fuel pump and check pink/black wire, lights stays on for a few seconds, so power is there., engine start spray works for a few seconds and dies. Next I need to check pressure on fuel rail. Don't have a Ford fitting for fuel pressure gage. Pump is new, we have bench test pump it and it worked. I hoping its not a computer so far. thanks, keep you informed to help others. I have watched U-Tube, videos, but when problem is not solve the computer is replace.I am making sure to check everything before buying a PCM.

If your fuel pump kicks on when the key is in the on position, then clicks off after a few seconds, it may be working correctly, as the pump does not stay on always without the vehicle starting. It is a lot less expensive to purchase the correct connection for the fuel rail valve and check there. You can disconnect the fuel line from the fuel rail and see if gas is coming through when the key is turned. Be careful, connect a hose to the fitting and place the other end in a container with a lid with a hole drilled to the proper size to accommodate the diameter of the hose, plus a little.

For any Ford 2003 f150 owners out there and you have to remove fuel tank, I just loosen bed and jack it up, but my truck is a an extended cap , couldn't get to fuel pump but it sure helped to remove some hoses and a connection on top of tank. Broke pressure sw on top of tank, it was so brittle cost me an extra $74 big ones to replace from Oreillys .There are six bolts, star type. I was afraid to strip heads so I used pipe wrench, crabbing bolts by the flat washer on head but it worked. I will put some lube on bolts and use electric impact wrench to re-install. This is what I did on pic.

GOT IT !!! I want to thank everyone for their input. This helped me to re-focus on my testing plus cost me approx $350 vs Dealership? These included tow, $104 new pump, broken pressure sw on gas tank $74, two new relays $26 and siphon hose $6.99. To be HONEST, don't know what was the culprit. This is what I did, replace two new relays PCM and Fuel Pump, cleaned PCM pins had small spider web & dust on bottom pins, new fuel pump and tested for voltage and voltage drop over & over again. At first no pressure from pump, I also notice on both relays the center pin # 87a had burnt residue, but both relays clicked when checked. After cleaning pins I started getting voltage to pins #87 and #86. After an exhausting testing decided to replace both relays and for sure the pump. I started to get the proper voltage at the inertia sw and down to the fuel pump. After completing installation I was nervous to turn key on, but started like a CHAMP!! Thanks again to everyone. Truck has been down since Dec 4th.