jeep shutting off at random

Roger Carpenter

New member
I am 66 and a very competent auto mechanic.. my 88 wrangler started shutting off randomly while driving .. I tested and tried everything I could think of found nothing wrong . finally fed up .. I ran a dedicated run circuit to a toggle switch under the dash to a fuse and to my coil . no more shutting off while driving . my only mental concern is should I put a voltage regulator in that line ? ANY THOUGHTS ?
 

Taking some old mental notes from my past experience , I found the same issue with my 81 CJ7. What I've found is that the signal wire to the coil is a resistor. Full 12 at cold start and resistive after a few seconds. After warm up, the wire opens and causes the shut down. Prior to this diagnosis, I did the same as you did, running 12v continuously shortens the life of the coil without the resistor wire. Eventually I replaced the entire factory setup and wired up an HEI distributor that also houses the coil and is designed to run on 12v continuos. This is for a V8 AMC 360 , if you have an I6 then it might not be the same cause.

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My 78 diagram calls for 1.35 ohm resistance. It is the wire, but.
If you could find 10 watt resistor, you could run regular wire to the coil.
 
well the problem is still not completely resolved .. it shut down again while driving .. next I'm installing a dedicated ground from the trigger to the block .. and cross my fingers !
 

Your block should have a ground straight from the battery.
 
so far .. my jeep has not cut off sense adding this ground wire from the trigger to the block .. but it was random before so I'm reserving judgement !
 
If that is the solution I'd replace the ground wires to the block and chassis. Look at posts about upgrading the big three.
 

well the problem is still not completely resolved .. it shut down again while driving .. next I'm installing a dedicated ground from the trigger to the block .. and cross my fingers !
What is this "trigger" you speak of?
 
I found a random shut off situation on my dads truck a few years back accidently. Start the jeep and start grabbing wires and moving them. His truck has a short where the wires go through the fire wall to the fuse box, every time you moved the wire the truck would shut down.. Hope it helps.
 
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