2013 JK No Start - Help! (Long Post)

Took the starter to an alternator and starter shop here in town. All he did was apply power four times and it worked properly each time. He pronounced it good and did the test for free.

However, is that all that is needed to test the motor: application of power? It seems to me that this would be the case, since it is an on/off device with no internal computerization or electronics. It is simple electrics.

He suggested I pull the alternator and he would test that for free, too. I will do that on Friday when I have the morning off. The load tester I ordered will be here by then, but I will not have had time to learn to use it (unless it is very simple to use) so I will pull the alternator for sure.

Learning about the TJ when it is not a vehicle I drive daily is a pleasure. Learning about my JK when it is down and I need it is not so much fun. I am grateful to have my old Accord to run around in.

Back on Friday after the alternator has been gone over.
 
Load tested the battery. It shows 13.8v unloaded, which is really weird. Under load it takes a dump to about 3v. Amazing.

Thanks to Jerry et al for the advice. I still have to check the alternator and wires (continuity/ground) but I am sure this was the issue. I hate electrical work because I always end up feeling like a moron when I have to do it. I suppose a good book would help with that. Any suggestions for automotive electrical books that are good for self-teaching?

Jerry, I love my Odyssey 34-PC1500T (that you pushed me to get a few years ago on WF) in my TJ so much that I bought the reverse polarity version (34R-PC1500T) for this JK. Now I can use a winch on the JK, too.

I was informed by a knowledgable JK guy that this was a CANBUS issue. If the battery under load delivers below a certain voltage the system will send power to nothing at all. Zero. Even if it could start up other vehicles just fine, as this one did. I started up the TJ with it. The TJ did not like it very much (it was slow to catch) but it started the TJ several times. I charged it up fully afterwards and then it started up the TJ much better. But nothing at all in the JK. Nothing. So it is *barely* bad, but the JK cannot tolerate that. Another reason to dump it and get me a 2003 or 2004 Rubicon for the wife...

The Odyssey from the TJ tested at 12.4v and like 10.5 under load. Is that good? I know it is acceptable but is that load rating okay? I also tested another known-good battery (in our 2015 Accord) and it also showed 12.4v and about 11 under load.

Finally, I tested a suspected dud. It tested as not fully charged (10.9v) so I do not know what to think about the load test, which showed the same voltage. I need to charge that one up fully and try again. I don't understand what I was seeing with that one. Like I said - suspected dud.

When the new Odyssey arrives next week I will see if the JK will start up or if I am still stuck for the present...
 
I dunno how the load tester could have shown 13.8v on an unloaded and disconnected battery. At full charge it is supposed to measure 12.6 volts, they generally put out 2.1 volts per each of the six cells. The only way I can see anything measuring 13.8v is if the engine was running and the battery was connected to the alternator.

10.9v while under load from a load tester indicates a good battery. This chart indicates what minimum voltages are acceptable at what temperatures...

Load Test Voltages.JPG
 
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Yep - 13.8v on the battery, fully disconnected and out of the vehicle. I used my multimeter to confirm. (Fluke 117)

It showed that on my first test, too.

Hit that button on the load tester, though, and it plummets like a stone to 3.5v - takes like three seconds to drop that far. Like I said: weird. It smoked, too. Definitely a bad battery.

Like I said, I will test everything else in the system too, but I won't have my Odyssey for 5 to 8 business days, which means about two weeks in real terms...

Thanks for that chart. I snagged a copy.
 
I have changed these on our two Hondas (one a "pack" and on the other separate coils on each plug, IIRC) and it is easy to do on those vehicles. I have zero idea how (or what) to check to see if they are bad. Looking forward to that link, Jake. Thanks.
 
Why does this battery show 13.8v though? That is bizarre. The tester works perfectly on all our other batteries, with the predicted results, and my Fluke showing the same thing.

Probably better to just not ask. It is going off to AutoZone for recycling soon, anyway, heh, heh...
 
Wade said:
Why does this battery show 13.8v though? That is bizarre. The tester works perfectly on all our other batteries, with the predicted results, and my Fluke showing the same thing.
Click to expand...
I re-read an old battery text and it mentioned it could read a higher voltage like youir 13.8v after a fresh charge by accumulating a non-chemical charge on the plates, kind of like a capacitor. That higher voltage would eventually go away as it sat a while, down closer to the usual 12.6v fully charged voltage.
 
I had just taken it off the charger. Cool! What is the name of that manual? I want to look it up. Thanks, Jerry.
 
If your battery drops to three volts under load, it's gone. Especially if these jeeps use a canbus system to communicate. Canbus is easily upset at bad battery's. I replace any battery's that drop below 10volts under load.
 
Yessiree, it was the battery. The TJ's Optima would not light it up because the nut holding the line clamped to the solenoid (not the protected wire in its connector) was loose and dirty, so far as I could tell. It must have gotten loose over time, then, the night before it took a dump on me I ran through a busted sewer line that had flooded the street. "Filth" had gotten into the gap. At the same time the battery had begun its natural death spiral. Coincidence. And my typical bad luck. So, the battery would have probably died at that time anyway, and the gunk in the starter solenoid line's gap made it look like something else was amiss instead, since no good batteries would start it either.

As I have read about the earlier 3.6L JKs (2012-2014) simply removing the starter and replacing it seems to clean off anything that could cause it to not work.

The very slow popping is just that particular starter's noise when it is not getting enough juice. It is definitely weird and caused me to suspect other issues. I think I will see whether I can source out some sort of rubber cap for the solenoid connection that will protect it from splashed up junk in the future. If it is *that* sensitive to normal driving garbage I cannot imagine them being all that good in the mud. So a cover will be found some day soon.

I reinstalled the starter. It had been a massive PITA to remove because of the driveshaft, and I did not have time to do that too. (It ended up taking much more time by not removing it.) For the reinstallation I *did* pull the shaft from the pinion. Installing the starter took less than a third of the time it took to remove it, INCLUDING pulling the driveshaft. Lesson learned...

Pulled the factory battery, dropped in the Odyssey 34R-PC1500, clamped it down and hooked it up.

First turn of the key: BAM! Started up better than it ever did with the OEM battery. The stocker is 600 CCA and the Odyssey is 850 CCA. I turned the key and it was running. Great battery for a jeep with add-on things like a winch or lights and such. Glad I now have that upgrade ——- and glad that the JK starts up again.

Thanks to all for the help and ideas. The main lesson here was that the JK's CANBUS will not work at all with a mildly tweaked battery. If it is about to fail your JK will not go. Period. It simply will not send juice to anything on the vehicle. It is like you have no battery installed, save for some odd symptoms. This battery was fully charged and would start up the TJ, but it was dead to the JK's CANBUS. Go figure.

My wife has informed me that we now have permission to sell the JK and use the funds to get a 2003 or 2004 Rubicon with low miles.

Since the JK is so much more computer-dependent and we are now *very* comfortable working on our 2003 TJ, it makes sense that our other jeep be one we can more easily fix ourselves.

Anyone think this would be a bad idea? This would leave us with 2015 and 2010 Accords, a 2003 Sport that is well built and then whatever we get to replace the 2013 JK Sport - like a 2004 Rubicon (that would be our 4th vehicle, coming factory built enough to be our second jeep). Ideas?


Here is the new (backwards) Odyssey in the JK. Nice batteries, these Odysseys...

fullsizeoutput_10b5.jpeg



Here is the model number in case, like me, you also own a JK and want this upgrade. It is a fantastic battery on the TJ and I expect it to be a gem on the JK, too, moving from 600 CCA stock to 850 CCA. Spendy and HEAVY (50 lbs.) - It is worth it.

fullsizeoutput_10b6.jpeg
 
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