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Stumped by Dead Engine

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Old Dec 26, 2022 | 01:05 PM
  #1  
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Stumped by Dead Engine

G'day all,

Hope someone may be able to help me with this issue. I'm not a good mechanic, but I can usually get by enough to keep rolling.
My 2004 F150 4x4 (210,000 miles ) had been running rough, so I pulled the coil lead on #1 no difference at all when I ran the motor, so I assumed the coil was bad
I replaced the coil lead but was running short on time so I only replaced #1, truck ran fine for about 20 miles, then my check engine light came on and it began to hesitate again, next thing I know the engine dies completely while I was driving. I got out lifted the hood and could smell a distinct electrical hot wire smell!
All the dash lights are dead, no key in ignition chime, no response all from turning the key, had to get it towed back home. Battery if fully charged, does this sound like maybe the wrong coil lead? and could it be possible I fried the PCM?
Any help would be appreciated.

Cheers

 
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Old Dec 27, 2022 | 08:24 AM
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You cant really use that method on this computer controlled engine . The pcm is too fast and it compensates. You had an electrical problem form your burning smell . Check your fuses find your electrical short .
I dont know what wire you are referring on number one cop , perhaps the plug in to the cop which is the cop control . !2vdc positive stands on one side with key on the pcm pulses the ground on other side the to trigger it. Most of us solder in the new plug and tape it or heat shrink it .
Perhaps ohm out each cop for correct ohms. More likely hot wire is going to ground somewhere in harness. You can use a a 12vdc bulb across the blown fuse to limit the current and give you a visual on the fault while moving wires and inspecting .
Each cop has its own pulse transistor per output ,doubt you could have ruined them all .
There is a common wear point near pcm rubbing on pcm wires where it goes under ac lines ,all kind of power in those connectors.
 
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Old Dec 27, 2022 | 09:16 AM
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All the dash lights are dead, no key in ignition chime, no response all from turning the key
If everything electrical is "dead", the problem is the battery or a battery cable or connection.

If something, anything electrical works, then the focus changes. It's still a power or ground problem, but not your PCM (based on the limited information available). Could be as simple as a blown fuse or fuse link. Given your report of a strong smell of burned wiring, I'd be suspicious of a blown fuse link.

Which engine in the truck? '04 Heritage or '04 NBS model?
 
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Old Dec 27, 2022 | 09:26 AM
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It's the Lariat 4x4 with the 5.4 engine
 
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Old Dec 27, 2022 | 09:38 AM
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Originally Posted by wombat63
It's the Lariat 4x4 with the 5.4 engine
Still need to know WHICH '04 version you have. "Lariat" doesn't tell us anything useful.

Also need your expanded observations regarding what does or doesn't work in light of my previous comments.
 
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Old Dec 27, 2022 | 09:46 AM
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It's the 04 New body
When the truck died I still had hazard lights working
The smell definitely came from the battery area, which is why I thought maybe the wiring loom to the PCM may have been an issue.
 
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Old Dec 27, 2022 | 10:23 AM
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Are the hazards the ONLY thing still working or not? If you want assistance, you have to give as complete information as possible. "20 questions" gets real old real fast, especially when they have to be repeated.


 
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Old Dec 27, 2022 | 10:40 AM
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NO everything is dead now, my hazards were working right after it happened, but are no longer working I thought I was pretty clear in my original post, sorry to waste your time.
 
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