conner Posted February 14, 2012 Share Posted February 14, 2012 Hey guys, I have a 2.5L, its not stock in my truck, the PO says it was replaced from a cherokee, didn't know the year though. Anyways my battery recently started going dead so I replaced the alternator and now it still didn't seem to stay charged so I took the alternator back and got a new one and It still goes dead. I checked the output on the alternator and it seemed to be working fine but the battery just doesnt seem to last long until I have to charge it again. I also tested the battery and it is good. Is there anywhere I should check for a power drain? I can't find any lights that don't turn off, not sure what else it could be, any tips? Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 14, 2012 Share Posted February 14, 2012 http://www.comancheclub.com/forums/viewtopic.php?f=2&t=33970&hilit=multimeter Link to comment Share on other sites More sharing options...
jimoshel Posted February 14, 2012 Share Posted February 14, 2012 Your going to need a amp meter. A light bulb can be used but their harder to use and get results with. Remove one of the terminals from the battery, Insert the meter between the battery post and loose cable. Go to the power distribution center or main fuse block. Start pulling fuses. Link to comment Share on other sites More sharing options...
smuth Posted February 15, 2012 Share Posted February 15, 2012 do you know that the battery is good? a bad cell inside will kill a battery overnight, esp. if it's cold. Link to comment Share on other sites More sharing options...
Jeep Driver Posted February 16, 2012 Share Posted February 16, 2012 do you know that the battery is good? a bad cell inside will kill a battery overnight, esp. if it's cold. This Link to comment Share on other sites More sharing options...
jcComanche86lb Posted February 16, 2012 Share Posted February 16, 2012 Did you load test the battery or did you check voltage with a volt meter? If a cell isn't making good connecting the battery can still show 13 or so volts until it's under load. Just thought I'd ask. Link to comment Share on other sites More sharing options...
HOrnbrod Posted February 16, 2012 Share Posted February 16, 2012 Yep, load test the battery at any Autozone or similar first, then commence troubleshooting festivities. :cheers: Link to comment Share on other sites More sharing options...
conner Posted February 17, 2012 Author Share Posted February 17, 2012 Yep, did the load test. Thanks for that link, I'll try doing that today. Link to comment Share on other sites More sharing options...
conner Posted February 29, 2012 Author Share Posted February 29, 2012 Ok so I tried testing everything, hardly any drain on the battery when nothing is on so there isn't anything on that could be draining it. Output on the alt is good, I put my practically brand new battery from my other car in it to see if that would help but no, I had to jump it today to get home. I have no idea what could be causing this, any other suggestions? Thanks Link to comment Share on other sites More sharing options...
Exgrayxj Posted March 2, 2012 Share Posted March 2, 2012 On a previous xj I was having a similiar problem, if it was parked for more than a day or so, flat battery. Just by accident I was poking around under the dash, and found the emissions box was warm, even with nothing on. Unplugged it and tossed it, no more problem. My neighbor to the rear has a Nissan pickup. He backs into his sloping driveway. And every night for about the last two weeks I notice his brake lights on, all evening and into the night. Not on when I get up for work. Would seem simpler for him to fix than have a dead battery every morning. :doh: Link to comment Share on other sites More sharing options...
conner Posted March 3, 2012 Author Share Posted March 3, 2012 It doesn't seem like there is something staying on draining the battery because I went to mexico for a week and it still started fine when I got back. It seems like it just dies from starting and then for whatever reason it isn't charging. Link to comment Share on other sites More sharing options...
Automan2164 Posted March 3, 2012 Share Posted March 3, 2012 Jumping in late here, but have you verified the running voltage reading on the truck? - Also, I know someone had mentioned the Parasitic draw test, but there is a proper way to do it, especially on newer cars: Disconnect negative batter cable. Put a ammeter and large fused jumper in parallel from the neg post to the neg cable. Cycle the key to on, but don't start. Turn off. Turn on the ammeter and see if you are getting huge numbers. If not, pull the jumper, now all residual power draw will be through the meter. Check your number. The reason you need to cycle the key with the cable on the jumper/meter is that some modules and things may stay on when you turn the truck off, but if you were to disco the cable - then put the meter in line, all the modules will have been put to sleep by the momentary lack of power. The fused jumper is so you don't blow your meter when you cycle the key. But, all of that is most likely a moot point on our trucks. Unless your radio is capable of some weird stuff, you should have no issues just disconnecting the cable. Rob Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 3, 2012 Share Posted March 3, 2012 But, all of that is most likely a moot point on our trucks. Unless your radio is capable of some weird stuff, you should have no issues just disconnecting the cable. Rob On the 91-95 OBDI MJ/XJ HOs (and perhaps the OBDII system also, not sure) disconnecting the neg cable causes what I consider an issue. At rest, no IGN ON, residual memory current (microamps) is constantly fed to the OBDI ECU to retain it's open/closed loop memory. Disconnecting the neg cable causes the ECU to lose it's memory instantly. For the ECU to completely "re-learn" it's residual settings, it needs to be driven about 100 miles or so, especially on a modified engine. It's a minor PITA as the idle is always lower during the process, and sometimes causes stalling when in stop and go traffic. Preventing this loss of ECU memory is easy by hooking up a common 9VDC battery with alligator clip leads attached across the neg battery post and cable (observing correct polarity) before disconnecting the battery neg cable. A healthy 9V battery will retain the ECU's memory for days since the draw is so small while you are working an electrical problem on your rig. Link to comment Share on other sites More sharing options...
Exgrayxj Posted March 3, 2012 Share Posted March 3, 2012 But, all of that is most likely a moot point on our trucks. Unless your radio is capable of some weird stuff, you should have no issues just disconnecting the cable. Rob On the 91-95 OBDI MJ/XJ HOs (and perhaps the OBDII system also, not sure) disconnecting the neg cable causes what I consider an issue. At rest, no IGN ON, residual memory current (microamps) is constantly fed to the OBDI ECU to retain it's open/closed loop memory. Disconnecting the neg cable causes the ECU to lose it's memory instantly. For the ECU to completely "re-learn" it's residual settings, it needs to be driven about 100 miles or so, especially on a modified engine. It's a minor PITA as the idle is always lower during the process, and sometimes causes stalling when in stop and go traffic. Preventing this loss of ECU memory is easy by hooking up a common 9VDC battery with alligator clip leads attached across the neg battery post and cable (observing correct polarity) before disconnecting the battery neg cable. A healthy 9V battery will retain the ECU's memory for days since the draw is so small while you are working an electrical problem on your rig. :bowdown: Now that you mention it, I have a little gizmo that holds a 9v battery and plugs into the ciggy lighter plug, just for that purpose...think I got it from Snappy, years ago. I had pretty much forgotten about it. i mainly used it so the radio wouldn't forget itself. Link to comment Share on other sites More sharing options...
HOrnbrod Posted March 3, 2012 Share Posted March 3, 2012 :thumbsup: :hijack: Just noticed your cat smokes unfiltereds. Not healthy. Gus the Cocker has basically quit now, but he'll still fire up occasionally if I let him. But he insists on ultra-lights, w. a maxi filter. Link to comment Share on other sites More sharing options...
Shane Posted March 3, 2012 Share Posted March 3, 2012 I am currently having the same problem. Let me know if you get a solution Link to comment Share on other sites More sharing options...
Exgrayxj Posted March 5, 2012 Share Posted March 5, 2012 :thumbsup: :hijack: Just noticed your cat smokes unfiltereds. Not healthy. Gus the Cocker has basically quit now, but he'll still fire up occasionally if I let him. But he insists on ultra-lights, w. a maxi filter. ;) I can't catch him but I think he's rolling his own... Link to comment Share on other sites More sharing options...
Shane Posted March 8, 2012 Share Posted March 8, 2012 Hey guys, I have a 2.5L, its not stock in my truck, the PO says it was replaced from a cherokee, didn't know the year though. Anyways my battery recently started going dead so I replaced the alternator and now it still didn't seem to stay charged so I took the alternator back and got a new one and It still goes dead. I checked the output on the alternator and it seemed to be working fine but the battery just doesnt seem to last long until I have to charge it again. I also tested the battery and it is good. Is there anywhere I should check for a power drain? I can't find any lights that don't turn off, not sure what else it could be, any tips? I was having this problem also until yesterday. I took mine to a local man that just deals with alternators and wiring. Come to find out my glove box light was staying on because it wasn't shut all the way. I know it is a shot in the dark, but I tightened mine up and it shuts fine now. No dead battery. Link to comment Share on other sites More sharing options...
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