Mdsnj

2004 5.4 motor will not turn over unless I reset the inertia fuel shutoff switch. After it runs it will start fine. An hour or so of sitting it will not turn over again. I bypassed the inertia switch with a jumper and the same thing happens.
What should I check? Any help would be great

Especial86

iTrader: (1)

Check the FPDM for corrosion. Its under the truck by the spare tire..

primalurges

Check the battery cable terminals. Mine were so Nablus corroded that the ring that attached to the terminal was beginning to separate from the wire, had a tin layer of material left. Given that you jumped the inertia switch with no change in condition I would think it's just a coincidence that it decided to turn over the last time you reset it. Also I believe inertia switch is just a fuel pump cutoff so that wouldn't affect your ability to turnover the engine.

techrep

iTrader: (1)

Do this ^^^^

TYM1

try your spare key, might not be ready your main key very well anymore
i think the motor will still turn over if the fpdm is shot, mine did anyway, it just wouldn't fire

Mdsnj

ok here is what I did, which did nothing.
Replaced the fpdm, it looed in rough shape. That did not work. I had to put the key to the on position for 30 seconds or so then to off. Repeat that a second time and then it fires right up like no issue. I then drove around running some errands shutting it off 4 times and it fired up perfectly. Got home a let it sit for an hour. Tried to start it and nothing again. Had to do the key on/off sequence and fired right perfectly.

What the hell do check?

primalurges

Sounds like an ignition switch problem to me. Not sure how difficult the plug from the switch is to get to but if you can get to it and get a probe on it you'll be able to test it's functionality.

Especial86

iTrader: (1)

Well that's a bit strange... Maybe a battery connection issue?

I wouldn't think its ignition if it eventually starts.
. But it could be something wrong with the tumbler.. Do you have an excessive amount of weight hanging from your keys when they are in the ignition?? Have you tried jiggling the keys and moving the shifter around as you attempt to start it?

techrep

iTrader: (1)

so... it cranks but does not start ?? when is the last time you changed your fuel filter ?

Mdsnj

I have been told by 2 people, mech's that it sounds like the fuel pump is loosing it's prime and a new pump is the answer. If the pump looses it's prime wouldn't the truck at least try to turn over? My truck does not turn over at all then fires up perfectly. By me doing the key reset thing is there a safety on the pump?