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Discussion Starter #1
Problem started with broken coil in the 3rd cylinder. Replaced coil and spark plug, reset ECM truck started but in limp mode throwing the same codes (3rd cylinder missfire). I checked the connector to the coil and it doesnt lock on like it should so I shoved it up tight and threw a zip tie on it for now. Tried to start it and now it just turns over but wont start? I tried re programming the key, no luck. Lastly I checked fuses and found fuse 78 in the engine bay was blown. (Powetrain control module voltage power 4 ignition coils) replaced it...it popped again without the truck starting. Help!
 

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Undo the 3rd cylinder coil wires and see if it pops again.
 

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Discussion Starter #3
I will try that tonight after work, if it is the wire/plug to that cylinder should I replace the harness?
 

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Try swapping a coil from another cylinder into 3 to identify if it is new coil or a plug/wire issue. I believe you can just buy a new pigtail if it is the plug.
 

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Discussion Starter #5
Tried swapping the coils, no luck. Disconnect cylinder 3 coil wire, same...nothing fuse popped both ways
 

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Did anything else change recently? try looking at the PCM and BCM connections. Do you see any damaged or corroded pins? check for bad grounds.
 

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This may be far fetched but you said connector dosn't lock on. Does your new coil have 3 terminals or 2 terminals inside where connector plugs in? if it is 2 terminal it is the wrong coil and will pop fuses . You need a 3 terminal coil. I'm in casa grande Az , i have a spare coil also set of spare coils if you want to try new set. .
 

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Discussion Starter #8
Bad454SS, I work late...just got up. I'll go check that out, wouldnt be the first time autozone gave me the wrong part
 

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Discussion Starter #9
Swapped coil spots, tried old coil...everything blows that fuse when I try and start it..
 

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Did new coil have 2 or 3 pins sticking out.? If it was a 2 pin may of damaged ECM. If new coil was a 3 pin ECM should be OK . Otherwise Trace and follow wires back from the coil all the way back to ECM make sure wire loom isn't hanging down touching exhaust and grounding out on passenger side. To me it sounds like you barely have a wire touching ground somewhere , and you were getting a misfire and it has progressed to a solid short now taking out the fuse.

Had a similar thing happen on my 2010 Raptor few months ago , wiring harness for transmission and oxygen sensors dropped down and barely started touching hot exhaust . Causing a slight miss at idle, running rich on bank 1 , parked it and ordered new sensors. The next morning started looking underneath and found burnt loom with one wire showing copper. ,that wire i traced to the bank 1 sensor heating circuit . Barely grounding out caused the sensor to flake out.

Sucks man trying to work in this heat. Good luck
 

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You can find the connectors on RockAuto.com

I replaced one on mine and it worked fine. Motorcraft stuff.
 

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Check wiring under truck passenger side where pipe goes up to Turbo see if anything is touching. Check entire loom for rubbing or abrasion.
 

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Discussion Starter #14
Is there a harness for both sides? If so, could I unplug the problem side and see if it starts or is that not possible on 3 cylinders or possibly do damage?
 

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I would start at the wires for the coil with issues and follow those wire colors back to ECM plugs.
 

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Discussion Starter #16
If off today, I'll be looking every over. I'll keep you guys posted and thanks for the help along the way! It takes a village!
 

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Discussion Starter #17
UPDATE- wires on plug were grounded together, I separated them coated them with liquid tape and it started! 1/2 block later died with same issue and somthing smelled like it was burning. FML. I'm going to try and replace the coil pack plug as maybe it was melted inside the plug? Short of that I'm looking at a whole used wiring harness for $300..
 

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At least you zeroed in on the cause.

Sounds pretty rare though, to be honest.
Haven't seen this ever reported around here.

Sent from my SM-N950U using Tapatalk
 

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Discussion Starter #19
So the wires were all together again when I checked everything in the day light. I separated them all, taped them up individually hoping the truck would start so I could get it back in the driveway and it wont start. I guessing the wires could be f'd up farther back...at this point I feel like replacing the harness is the next logical step?
 
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JarodAZ
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