EmmJay

Good news... Got it running today. I ended up rechecking that all electrical connections were tight, rechecked all the fuses, then pulled a plug while a friend cranked the engine and found that, in fact, the spark was there. I then pulled the cover off the carb, cranked it once, reinstalled the cover, cranked it again and it fired right up. The Neutral Safety Switch was to blame for the truck not starting in Park. When I crawled under today I found that a bracket on the driver's side of the transmission was loose. I tightened it up and the Jeep now starts in both Park and Neutral.

'86 MJ with the 2.8 V6 and 3-spd auto. transmission. The truck will not start OR crank in Park, and will crank and crank in Neutral but won't fire. Any ideas as to what could cause this? Recently I replaced the flexplate, which required removing and reinstalling the transmission. After the job was done, the truck fired up right away and sounded awesome. About three minutes later the engine cut off and smoke appeared under the hood. Realized pretty quickly that it was electrical (the large positive starter wire had melted on the exhaust manifold, causing a short). I replaced the positive battery cable but the truck still didn't start. Replaced the starter relay--still no start. I then tried starting it in Neutral (instead of Park) and it cranks and cranks but will not fire. Using the screwdriver-in-the-spark-plug-wire trick, it seems as though there's no spark. It sounds a little like the problem could be a bad or misaligned Neutral Safety Switch (NSS), but that would prevent the starter from energizing, wouldn't it? And the truck started up just fine in Park after the flexplate replacement, and I haven't messed with the NSS since then. I'm wondering if the no-spark condition is due to some other damaged caused by the short... If so, what's the most likely culprit?

That helps. I'm feeling pretty confident it's externally balanced. I'll post here what I find...

Thanks for the replies. Yes, I know I can figure it out once I get everything apart, but I'd like to know beforehand so I can order the correct flexplate. Otherwise I'll probably just order both and return what I don't use. Any other insights on this? I feel like is a pretty big detail that I'm sure someone knows something about...

Hey all, just bought my first MJ last weekend and have been glued to ComancheClub for a week straight! Looks like there is lots of good information here and I look forward to contributing as I learn more about the truck. My DD is a '97 TJ, but I've had my eye on Comanches for a long time... Picked up a 1986 Custom 2.8L V6, 3-spd auto, 2WD. Interior and exterior are in excellent shape, and the truck starts and runs decently. Got an excellent deal on it knowing that it needed a flex plate replacement. My question: I have read that the 2.8's were made both externally and internally balanced, depending on the year. I've read on some threads that they switched from externally to internally in the middle of the '86 year, while other threads state that internal balancing did not come along until '87 or '88. Can anyone tell me for sure if there's a definite way to tell if my '86 engine is internally or externally balanced? I'd like to order the new flex plate ASAP so I can get the work done before it gets too cold outside... Thanks for the help.