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Stock JK TechBulletin board forum regarding issues with OE (original equipment) components of the Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) such as factory suspension parts, engine, transmission, body parts, interior fixtures and the on-board computer.
I have just over 104,000 miles on my jeep and about a month ago my coil cracked on top left coil looking at it mounted. I replaced the coil, plugs and wires and every thing has been good until today, as Im driving to work I get the misfire again and engine light. I pull over to look at the coil and between the top two plug wires is bowed out and ready to explode. Any suggestions what may be causing this or did I maybe just get a bad coil? I haven't had any issues like this before so just curious if anyone else has had them before, thanks in advance.
Update: I just removed the coil and the back is split open with black melted liquid coming out of it.
Last edited by 08 Wrangler; 06-24-2015 at 01:50 PM.
I have just over 104,000 miles on my jeep and about a month ago my coil cracked on top left coil looking at it mounted. I replaced the coil, plugs and wires and every thing has been good until today, as Im driving to work I get the misfire again and engine light. I pull over to look at the coil and between the top two plug wires is bowed out and ready to explode. Any suggestions what may be causing this or did I maybe just get a bad coil? I haven't had any issues like this before so just curious if anyone else has had them before, thanks in advance.
Update: I just removed the coil and the back is split open with black melted liquid coming out of it.
I have the. 2007 jku 3.8 and have had same problem . Replaced multiple coil and plug wires same keeps happening. Have you had a solution ?
Could be a ground issue. Get a digital multimeter and check the resistance between the ground wire on the coil pack and the negative battery post. See if it is high and how it compares to the other coil packs, especially on the other bank.
Ok same issue y'all are having Ive gone through 3 packs now getting the 4th in the morning, all of the coils are Mopar could packs as well, after the first pack about 3 months ago I replaced the pack wires and plugs.....
A few things I noticed, the packs are fragile especially if over torqued the plate they mount to typically isn't flush so if you tighten them too tight it twists the pack ever so slightly causing the cracks, this happens if you drive one bolt home and suck in the other one too it has to be installed like a flywheel almost tighten it slowly and equally till it's finger tight and use lock tight to get it to stay not torque.......
On the side of the engine from the underneath you can get access to the packs ground wire, it goes to the block there are 2 wires that go there clean them all I can't remember exactly what one is to the pack but it's on that motor ground for sure.....
3rd thing I noticed is that if you managed to crack the ceramic on your plugs it can cause this as well, so check all 6 plugs for damage to the filament......
Hopefully this helps some of y'all get a grip on this and please keep in mind I am no mechanic just a pissed off jeep owner so take my advice at will
Check voltage on the low side of the coil when engine is running. May be too high causing insulation breakdown, due to higher voltage, on the high side or too low 12V causing more current (aka heat) to flow. Use the sharp prong attachments on a multimeter to 'dig' through the insulation of the 12V wires or start first with system voltage with engine running at the battery or alternator main terminal.
Check voltage on the low side of the coil when engine is running. May be too high causing insulation breakdown, due to higher voltage, on the high side or too low 12V causing more current (aka heat) to flow. Use the sharp prong attachments on a multimeter to 'dig' through the insulation of the 12V wires or start first with system voltage with engine running at the battery or alternator main terminal.
Do you have pictures or something describing this better as far as I know there is no "ground wire" on a 08 coil pack because the pack just sends powers to the plugs that ground out to the motor creating a spark, the block has good ground and the pack is melted it's running on 2 cylinders at best there has to be a way to test it without risking my cats with unburned fuel
Check voltage on the low side of the coil when engine is running. May be too high causing insulation breakdown, due to higher voltage, on the high side or too low 12V causing more current (aka heat) to flow. Use the sharp prong attachments on a multimeter to 'dig' through the insulation of the 12V wires or start first with system voltage with engine running at the battery or alternator main terminal.
I uploaded the wiring diagrams for my 08 wrangler page 15 had the coil pack wiring, there is no ground wire to check there is 3 coil control wires and one brown white wire that ties into 02 sensors the injectors and I think the asd or something else too
I uploaded the wiring diagrams for my 08 wrangler page 15 had the coil pack wiring, there is no ground wire to check there is 3 coil control wires and one brown white wire that ties into 02 sensors the injectors and I think the asd or something else too
Update, the 12ohm resistance is from the injectors and it's on 6 pins just spread out, after Inspecring all 3 coils I had still that got melted I noticed a trend, middle coil every time, not sure what it means or where to go from here I guess to a shop
Couldn't find the coil in the pdf above, so here's a schematic (below). Note that the coil pack has 4 pins, switched B+, and the other 3 pins are for the PCM to intermittently sink (connect to neg ground) like ignition points did in an old-fashioned distributor. Have you checked for codes (e.g. P2305), if not that may provide info to troubleshoot with.
06-24-2015, 01:17 PM
Multiple blown ignition coils on 08
