Ignition Coil wiring

[rjtrinity]

I had a great story here of my new-to-me Explorer dying out in the woods and the work I've done to it up to now, but that post had gotten too long so I'm giving the condensed version now. Anyway, the current situation is that I installed a new coil pack (old one definitely bad - very big crack) and had a very nicely running Explorer. For a few minutes. Then on the test drive it coughed once and died. I had cleared the codes before the test drive, now after it died it has codes for all 3 coils. The fuse for the coil was blown (2nd time). Replaced the fuse and it started, but runs terribly. Codes for 2 and 6 misfire. The coil looks perfect and the ohm meter says it's within specs. That and that it ran nicely for a while makes me thing the coil is OK. The repeated fuse blowing makes me lean toward a short in the harness and with the coil looking/testing fine the misfires on 2/6 could also be a short in the harness. So what I'm wondering is: 1) Is there a common point where the wiring to the coil pack goes bad? And 2) Can somebody describe the path of the wiring between the coil pack and the PCM? (pretty direct through the harness to connector X of the PCM, or via the fuseblock or...) Any other suggestions? Thanks in advance... -rj

 

[decipha]

The coil trigger wire comes direct from the ecu is doesnt go anywhere else

The coils get a shared power feed, make sure that wire isnt getting tapped anywhere and that its not frayed, pinched, etc...

lastly, check your wireset, if any of the wires melted to the exhaust or are not connected to the plugs securely it can cause the same problems

 

[rjtrinity]

The coil trigger wire comes direct from the ecu is doesnt go anywhere else

The coils get a shared power feed, make sure that wire isnt getting tapped anywhere and that its not frayed, pinched, etc...

lastly, check your wireset, if any of the wires melted to the exhaust or are not connected to the plugs securely it can cause the same problems

Thanks for the info. I did find the wires from the PCM. They're on the bottom plug, among the row of pins on the outboard side of the plug if that helps someone else sometime down the road.

 

[rjtrinity]

I've untaped and unwrapped a bunch of the harness, looked, tugged, twisted and pushed and can't make an ohm meter read anything but good between the coil pack plug and the PCM plug - neither opens nor shorts, at least not shorts to ground. Also from the coil pack plug to the fuse block for the positive wire. Of course there's about 10 - 15 inches I can't unwrap or barely even see under the intake plenum. Anyway, I put it all back together, fired it up and exactly the same. Oh, and I was mistaken earlier. I said it had codes for 2 and 6 misfire. Those codes were earlier and I haven't seen them since the coil pack replacement. What's setting now is actually the code for "Coil C primary/secondary circuit malfunction" - P0353. To test the operation of the circuit I pulled the boot off of the #6 plug, put a piece of wire in it running to near a good ground, fired up the motor and noted a good spark. Did the same on the #2 and similar good spark. (Both were able to jump a lot more than .054!) So the circuit is operating, at least as much as getting spark to the boot. I guess I'll pull the plugs tomorrow.

 

[fordapprentice96]

i had the same problem. i replaced the coil pack and it ran good for a few weeks. then it started misfiring on 2 and 6. pulled the wires off when it was running from the coil pack and they wouldnt arc like the other cylinders would. not sure if its a wiring problem or a failed coil pack. i replaced my plugs and wires a year ago

 

[ESGWheel]

check out FordTechMakuloco on his youtube site. He as an upload called "Ford Ignition Coil Primary Codes P0351-P0360 Diagnostic Walkthrough"


hopefully that will help...

 

[fordapprentice96]

check out FordTechMakuloco on his youtube site. He as an upload called "Ford Ignition Coil Primary Codes P0351-P0360 Diagnostic Walkthrough"


hopefully that will help...

that helps for people with coil on plug style vehicls. i have a coil pack with wires. my problem i think is wiring from the pcm to the coil pack or the pcm themself

 

[ESGWheel]

Oops, sorry... to many beers on a Sunday...