Another crank, no start issue...

[ghetdjc320]

17 minutes ago, acfortier said:

Interesting... it's worth a shot! Thanks for the tips. Coils are cheap enough, and I can bring the battery to get tested at the same time. Honestly, not sure how old the battery is--it's been in there since I purchased it.

May be time for a new battery. Most parts stores just test the standing voltage but they really need to be load tested under a heavy cranking load. Hopefully you can just return whatever isn’t needed/used 

 

Its entirely possible your issue lies elsewhere but a couple a quick stops to the parts store may save a ton of time chasing phantom issues.

[Tsalagi]

2 hours ago, ghetdjc320 said:

Just remember, all of this can be due to battery not giving a full 12v during cranking 

Grab a replacement coil from the auto parts store and throw it on along with a good battery if you have an extra or a jump. It’s really hard to catch that 5v pulse on a regular meter. I’ve tried, and was also convinced of a bad ecu. Have had this happen on 3 HOs so far. Each time it’s been either coil or battery. 

This has been my experience as well. A "weak" battery just won't send the correct signal to get everything kicked over. It will turn over fine but will not start.

[acfortier]

Well, now I'm just embarrassed. I like to think myself as a technical/mechanical person, but sometimes these problems eat me up. Tried to do component isolation before firing the parts cannon at it, and I could have swore I was able to see the 5V at the ignition coil previously, but I must have gotten it mixed up with something else.

 

Picked up a Carquest Premium coil from Advance for $40. Was surprised to find it say Made in Poland on the box. I assume Poland must be better than China, at the very least, right?

 

Popped off the old coil, popped on the new one, and voila--it turns on. Since I was curious to confirm that it definitely was the old coil (and not get a possible false positive), I put the old coil back on. And it fired up again. WTF? But, the connector was yet again loose, just like it was previously--I was able to apply pressure to it to get the Jeep to stumble and turn off. Also, compared to the new coil, it was noisy and I could feel vibrations when touching it.

 

So I took the old one off again, cleaned up the bracket and bolts used to secure to the bracket. Also, the connector was way tighter on the new coil than the old, and I wasn't able to do the same thing to get it to stumble like previously.

 

My guess is either that coil is bad/was going bad, it had a poor ground through the bracket that connects to the body, and/or the connector input was loose again.

 

Thanks @ghetdjc320 for urging me to go the route of a new coil. It had previously tested fine via resistance, but it very well could have been a poor ground/poor connector.

[ghetdjc320]

Awesome! Glad to hear you got it working. Maybe plan for another battery soon as well 

[acfortier]

Heh, so the updated part of this is that the issue was definitely not fixed and still intermittent. I've always been leery of my battery cables, since the negative was definitely replaced (or painted?) at some time. and the terminals were a bit crusty. Bought the JeepCables kit, and did the Big "4" (I didn't bother adding in the fuse between PDC and Alternator, nor did I replace the firewall to valve cover). It seems like the battery negative to englne block was significantly shorter than what I had and forced me to reroute it, but it's still a bit too tight than I'd like.

 

After that, fired right up. Fired up a couple other times randomly, and decided to try to go for a ride to the town dump for some yard waste dropoff. About 30 mins round trip, no issues. So now I'm REALLY hoping it's resolved... lol