the other day while driving on the highway my yj just shut off as if someone turned the key off. while trying to diagnose it yesterday i found that it had no spark from the coil(bypassed plug wire so wire is not to blame). thinking it was the coil i changed it out with a new one i already had. still nothing. then i tested it again...suprise spark. so i started it and within a few minutes it died again and would not start.

-its carbureted so no crankshaft position sensor, correct?
-if i'm not getting spark from the coil, the problem must be before the coil and not with the dist. correct?

tomorrow i will look at the ignition box and possible get a couple from the junk yard

I just had a similar problem happen on my CJ7. On two occasions on the same day it just died. However, mine was due to a total loss of power to the fuse panel under the dash. I was EXTREMELY lucky that both stoppages occurred while the Jeep was sitting in the garage. I had just been out earlier riding around.

After some troubleshooting, I discovered that a 14-year-old splice under the hood, in the main feed wire from the battery to the fuse panel, had become corroded at one end of the splice. Moving the splice slightly caused it to connect and then disconnect. I was lucky that both times it disconnected, I was sitting in the garage where I could trouble shoot it.

This splice was installed back before I started using Star Brite Liquid Electrical Tape on all terminal and splices under the hood. After I repaired the problem, I goobered it up good with LET.

So, don't always assume that some component has gone bad. A lot of times it's a bad wire or poor electrical connection. In your case, I'd start by checking two things: (1) Does the coil have voltage on the hot side anytime the key is in RUN? (2) If that's OK, does the ground on the low side of the coil come and go when the engine is being cranked? If the answer to either of those questions is NO, then you know where to start troubleshooting. BTW, a multimeter is invaluable in troubleshooting these electtrical problems. I carry one in the shop and another one in the tool box in the Jeep.

New spark (ignition) boxes are so cheap why waste your time looking for a used one? It is on the drivers side fender well and is attached by screws from the tire side of the fender.. Lots of guys carry a spare everywhere they go..
It is about the easiest lectric part to replace.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

The ignition on the old Jeeps is not very good or very reliable.I have an 89 YJ with a 4.2L and the best thing I ever did was to put a HEI ignition on it. I have gained better MPG and more power, plus the acceleration is much better. This ignition does away with the old Distributor and the Duraspark box. The cost is about $190 from CRT Performance.

Truk guy. Any performance gain from that swap was from disconecting the computer to the dist! NOT from the hei!
You would have had the same performance gain from simply disconnecting the computer from the original dist...
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

Can't agree with you less. The CJ's with Motorcraft mag pickup distributor, ignition module, and Motorcraft 2150 carbs were some of the most reliable made. Easy to tune. If something did break, easy to replace.