wdavern

So I've been having this sporadic problem lately where I go to start my Jeep after it's been running, and it's like the battery is drained. Not fully dead just drained to the point where it will not turn the starter over enough. But if I leave the Jeep for an extended amount of time and let it cool off it will start up with no problem. I believe I've narrowed it down though to when it mainly happens, which is when the engine is hot and the Jeep is shut off for a short amount of time. For example when I went to get a hair cut the other day I had been driving around running errands beforehand so the engine was at regular running temperature. I was in the barber for maybe 20 minutes and when I came back out to leave the symptoms described previously occurred: when I tried to start it it sounds like the battery is drained but not fully dead and the starter won't turn over enough to start the engine. I replaced the battery and alternator about 2 weeks ago and the starter I replaced in mid February (2018). I had those 3 things all tested both at AutoZone and by my friends dad who is a mechanic and has a professional tester at home (old Snap-On model or something I'm not 100% sure). He also helped me go through any additional wiring I had which isn't much, only two led pods on the windshield, a subwoofer and a Badlands winch. The winch is the only thing directly wired to the battery, everything else is properly wired to turn on only when the key is turned in the ignition or the car is running. The battery, alternator and starter are all Duralast components purchased from AutoZone, I'm just wondering if maybe I got faulty parts or the starter is crapping out on me early. Any suggestions on where else to start looking would be greatly appreciated!

karls10jk

Are you getting any codes? Some codes will not show up as a CEL but rather just store in the memory, that may be something the scanner can pick up. Connections are tight on the battery, right? It sounds like you've got increased resistance happening when the wires are hot, maybe you've got a small break in the line somewhere....which line though, tough to say.

wdavern

After reading this I tried to trace the starter wires first as far as I could figuring if those wires were heating up and causing resistance then it might make sense for the battery not being able to get enough juice to the starter. Made sure the starter connections were tight afterwards and ended up finding a small hole in my starter, somehow some of the housing cracked. I got a new one under the lifetime warranty, threw it in and even got heat shielding for where the wires were somewhat close to the exhaust. Took it for a test drive around town and on the highway to heat it up and when I got home and shut the Jeep off and tried to start it again resulting in the same symptoms occurring. Go figure I thought the cracked starter had to be the source of the problem. Going to have to keep searching for whatever is heating up and causing resistance

wdavern

Tried leaving the Jeep overnight since usually it would start right up once it cooled down. Went to start and it was almost like the battery was completely drained worse than the previous symptoms. It wouldn't start even when we tried to jump it so I had to pop the clutch to get it started. Once I got it running I noticed the red battery light was on on the dash (which wasn't on previously)

Quyen

Google this and read the full post on the first link that shows. It's apparently a sensor in the transmission.

"jeep jk sometimes won't start after just being shut off"