Thanks for pointing that out. I got you and OP mixed up. Definitely let us know how it goes.
Ok, electrical geniuses got a puzzle for you
- Thread starter 2006_LJ
- Start date
Thanks for pointing that out. I got you and OP mixed up. Definitely let us know how it goes.
Just another data point for you.
I get a consistent 1V drop between the dvom reading vs obd2. The voltage comes up at both ends but the difference remains whether engine is running or not.
I don't appear to have an overcharging problem, as even at fast idle I'm only at 13.5V measured at the battery. I never see above about 13.6 even on my external USB charger/voltmeter, so I'm definitely not exceeding 14.6 at the battery.
I got 11.4 on OBD2 and 12.4 on meter with key on engine off. I did just charge my battery from a no start condition today after sitting for a couple of weeks, so it's a little, but not much, lower than normal. The no start is why I'm poking around. Battery looks pretty old and I can only find 11mA of steady state current drain so I think I just need a new one.
I get a consistent 1V drop between the dvom reading vs obd2. The voltage comes up at both ends but the difference remains whether engine is running or not.
I don't appear to have an overcharging problem, as even at fast idle I'm only at 13.5V measured at the battery. I never see above about 13.6 even on my external USB charger/voltmeter, so I'm definitely not exceeding 14.6 at the battery.
I got 11.4 on OBD2 and 12.4 on meter with key on engine off. I did just charge my battery from a no start condition today after sitting for a couple of weeks, so it's a little, but not much, lower than normal. The no start is why I'm poking around. Battery looks pretty old and I can only find 11mA of steady state current drain so I think I just need a new one.
Awesome thank you! That’s what I’m looking for, sort of odd that the obd2 reads that way I will have to dig further into the wiring when I get a chance. I have an external regulator installed right now to keep the voltage below 14.5
Before I share info on what fixed my no-start, I should begin by asking if you’ve done a parasitic draw test with the system off? Good place to start that I’d hate to not mention.
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Fwiw, I had a no start with no codes, and ended up finding two problems. I fixed both problems and doing so solved my issue.
The easier of the of the two is to check your spade connected to your starter (for a loose connection/corrosion/breakage). My wire insulation was completely missing from six inches leading up to the spade connector. Spliced in a 12 awg wire iirc and spade connector.
The second problem involved the melting of the plug with the ignition wiring near the flasher relay where it connects to the turn signal / multi purpose switch assembly. My plug had melted/deteriorated and pins were touching. Fixing both also seemed to settle my idle down and may have lowered by charging voltage (can’t remember those details so well).
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It started right up after sitting on the charger for a couple hours. It's done this a couple of times when sitting for 2 weeks. I checked for parasitic draw but only found 11mA which is probably what gets drawn just to hold the memory in my radio and PCM.
Any voltage drop between your alternator and battery?
If the alternators good and connections are clean and tight maybe the battery isn’t long for the world?
Edit: fwiw sometimes batteries don’t come back to proper health once they’ve hit a low charge state. This happened years ago to a truck battery that wouldn’t start if I left it for a couple of weeks. The root cause of the bad battery was lack of sufficient alternator output to match the load I was putting on it (good lesson learned).
Btw, depending on the charging method it might take up to about a day to fully recharge a battery. It’s usually overnight at a minimum for me using a 1A wall charger
The difference between 80% and 100% is greater than one would think bc it’s not linear. That seen when our phones charge up super fast from 10% to 20% but take longer to go from 90% to 100%.
Maybe add distilled water to the battery if it’s low? Also, I’ve read where you can continuously trickle charge the battery for a week to ten days to recondition it. I’ve never tried that as I’ve always gotten a new battery if I’ve fully charged it only to have it fail again.
It's been doing this for the entire 2 years I've owned the LJ, and it was already building crusty blue corrosion on the positive terminal back then. Usually it doesn't affect me because I drive it at least a couple of times a week. In the past it's been when I had it taken apart for some project that took me a while, like my trans swap, my front locker install, etc. We had an unseasonably cold week (I'm still running without windows) followed by being gone to visit family for Thanksgiving for 8 days so it sat, and as I've come to expect, I got about a quarter second crank followed by rapid starter clicks.
I just put my automatic charger on it for the afternoon and it's starting now, though a little sluggish. I'm sure it'll need some more driving or charging to come back.
It's a sealed top so I don't think I can add water to it.
I'm really not trying to hijack this thread though. I've been looking for an excuse to get an AGM and this might finally be it.
Yea man best to not over work the alternator if you can avoid it. Best of luck.
I wonder if the battery temp sensor is causing your issue... I have seen a similar issue in some older Dodge trucks that had near identical symptoms.
If I'm not mistaken, some do and some don't on the 05-06 models - I believe the ones that don't have a battery temp sensor utilize the air temp sensor on the front of the grille.