Fixed: 05 mustang 4.6L V8 no start

05 ford mustang with 4.6L engine. Crank no start condition but will start and run for about 10 seconds and die on occasion. Had a frp sensor fault in memory so decided to start my diagnosis with fuel. No fuel pressure. No fuel pump current at the power distribution box. Checked power at the pump control module. Pcm to module wire has power. Module to pump wire has no power. Tried to jump power through that wire down to the pump to make it kick on but to no avail. I did put a module in it but I'm concerned I missed something or the pump is just completely shorted out. Help me out guys

Hey randy! Grabbed the diagram for this Mustang, for reference:



To be clear, you found power on the white wire, pin 5, at the FPDM? But found no power on the pink/black wire, pin 4, going to the pump itself, correct? Were these checks done KOEO, KOEC?

Do you recall which codes were stored in the PCM? P0191 is the most common FRP code, but I was more interested in any P12XX series codes, as these are usually codes generated due to a communication issue with the FPDM.

Given that you saw no power on the pump feed, I think my next move would be to check the FPDM ground. That's the black wire, pin 3 at the FPDM. A voltage drop issue on this wire would absolutely cause the FPDM to go offline and not power the pump as designed. Do a voltage drop test on this wire with the engine cranking and let us know what you find.

you tried to put power on the pk/bk wire that goes from the module to pump?? it didnt work? did you supply the pump a ground at the same time to? the pump should run with a power/ground provided from you. if it doesnt run id be concerned about that

The diagram really helped me out on this one. Didn't know or even think about the inertia switch on this one. It was in the driver's kick panel. Reset it and was good to go. Did do some pump measurements and still suggested a pump and filter to this customer. Only 30psi and was running very slow. 8 armature humps within a 100 or 120 ms window. Thanks for the help

Sweet, fixed! This thing wasn't in a wreck or something? Just curious how the inertia switch got tripped.

Not 100% sure. Did have any evidence of a wreck that I could see unless it just came from a body shop.