Valvoltec

Hi great its running again,and all that for a broken wire! Always found myself that the more baffling the fault appears the simpler it is when you sort it out.Is the jeep back on the road again or are there more jobs to tackle?

The Rooster

Glad it's fixed if it was me I would check all the other ground wires just to make sure all of the other ones are good

RERJR

I recently canceled a fishing trip midway to Canada because my 1993 JGC 4L w/260,000 started stumbling at a stop sign as if failing to engage the clutch with a straight stick (also like a stuck torque converter lock-up release valve). I've professionally wrenched for over fifty years and immediately suspected the problem to be electrical and evasive so I did a 180 in the middle of nowhere and returned home. My hunch was right. She died one mile from my house and a buddy towed me home, boat trailer and all.
Before we even attached the tow line I determined I had spark, fuel and compression. Indeed a puzzle that I was fortunate to have avoided crossing the narrow toll bridge into Canada, the tight alleyways at Canadian Customs or the narrow causeway that island-hops to my favorite fishing spot. Long story SHORT, after checking everything else and finding all good I carefully measured the spark jump the coil could put out which should be => .5" but it faded and became intermittent at 1/4" so I replaced it even though the resistance on both prim. & sec.loops measured squarely in the middle of factory specs. BINGO and sweet music as my 4L once again sounded smooth as a sewing machine (except for the trademark rattle in its original CAT).
FYI I've found a coil failure to be extremely rare so I double checked everything before parting with the $50 for the coil. A basic fact about spark is that resistance through the compressed fuel/air mixture in the cylinders is multiplied about 3 times and a spark that will jump .035" in open air may not do so under compression. Everything I am familiar with that has "electronic ignition" (gross misnomer) including outboards requires a spark capable of jumping a half an inch in open air. I suspect my coil had an internal crack or "leak" and was taking the path of least resistance to its steel core.
Thank you to everyone who contributed their thoughts and experience. As with a poor or missing ground there is no fault code thrown for a leaky coil and you have to deal with it the old fashioned way.