Hey guys. Last night I was driving and my truck just died. It's an 04 SCREW with a 5.4, 4x4. A buddy came out with a scantool and it said it was unable to connect to the computer on the truck. Another buddy said that the battery was probably garbage, and the scantool wouldnt be able to connect because it didn't have enough juice. It seemed to have ok power, but it wouldn't turn over at all. I tried jumping it and got it to turn over, but it wouldn't fire. When I unhooked the jumpers it didn't turn over at all, so I replaced the battery.

I tried starting it again, and it didn't turn over. I now have a ticking/humming sound coming from what I believe is the evap purge valve. Its a small thing on the firewall by the master cylinder with two lines that look somewhat like fuel lines, with a shrader valve, and one electrical plug. Now the truck does turn over, but still won't start, and I still get the hum/tick. I can't figure out what this thing is, or if it is causing my problems or not. Any help or ideas would be greatly appreciated

 

Try the fuel pump reset switch

 

as far as i know your purge valve will never keep your truck from starting. check the battery cables, make sure there isn't a ton of corrosion, make sure everything is tight and check grounds. from the way you describe it, it really sounds like a battery.

 

my 97 did that once and it turnes out to be bad battery....they can do some strange things sometimes.check all connections etc... had a taurus that would just die if i hit a bump just right ...me crazy.. was a loose main ground wire.

 

Here's an update... I got the battery good and charged up and it turns over like a champ but still won't start. I tried resetting the inertia switch with no change. I started checking fuses, and the "Fuel Injector/PCM Power" fuse was blown so I switched a new one, but it still doesnt start. The hum/tick from the purge valve went away at this point. I couldn't hear the fuel pump running with the key on, and hitting the tank with a mallet didn't start it, so I pulled the inertia switch and ran a jumper wire to see if the switch was bad, which it apparently wasn't. I thought it might be bad because I assumed resetting it would make the button seat and click in when I reset it, but apparently that's not the case. So I think it's the fuel pump, but I can't be sure. My truck is on a street 10 miles from my house so it's hard for me to do too much with it today

 

Try the fuel pump driver module, its a 150 dollar part, mine went on my truck, its near the spare, do a search for fuel pump driver module and you'll learn more. It may be completely unrelated to the battery

 

make sure you check all the fuses. If you ahd one blown there could have been one in the engine compartmwnt or in the cab that blown too.

 

Same thing (above) happened to my 2005 and it was dead in the water, but turned over fine. Now that you have a good battery, I'd check for codes again. If the driver module is gone, you won't hear the fuel pump run with the key in the on position either.

 

Thanks! I'm gonna check the FPDM right away in the morning. I've been searching online, is this a dealer only part? It wasn't even on Tasca. Should this throw any codes or anything to pinpoint it? Or should I just replace it if it looks bad?

 

I'd kinda be curious about the blown "Fuel Injector/PCM Power" fuse.
Fuses dont just blow for no reason either a component went bad or something shorted to ground.

 

I got mine at the dealer, they go bad, so itd be worth replaxcing it anyways, the newer p n has a different mounting system than the original that stops salt and crap from rotting it out

 

It is caused from the FPDM circuit board getting corroded up... bad design.

 

So do you think that maybe the FPDM went bad and that caused the blown fuse? Is that plausible?

 

As Mr.Spock would say...Sounds logical

 

Yes... anytime something can potentially get shorted it SHOULD be protected by a BUSSMANN fuse. Especially something like that. Thus since it shorted the "Fuel Injector/PCM Power" fuse, I would bet money that the FPDM caused the short thus blowing the fuse saving your truck from a possible explosion, burnout PCM, and/or fire. That's what fuses are for and it did what it was intended to do -- blow.

Also if you notice "Fuel Injector/PCM Power", that FPDM has a circuit board too just like the ECU.