2001 xj loosing volts

[01XJ]

im having a problem with my 2001 xj just started the other night we left from having dinner at a resteraunt the other night got in started fine it was my g-mas b-day so we went to say hi pulled in driveway was there about 10 min went to leave and it wouldnt start stil had a liitle power but it was like a dead batt. so we were going to jump it when the wife kept trying to start it then out of the blue everything came to life again started up and we were off the next night we are in a car wash when the check gauges light comes on i look over and volts is gone shows zero.all lights are dim i rev it up and it jumps to 14 volts and no more probs that night runs like a champ....next morning get up to leave and there is power to everything again but it is dead wont start shows we have about 12 volts i wiggle every damn wire in and under the hood of jeep nothing so we leave it for about 2 hrs come out try it nothing still keep trying about every 15-20 min and then all of the sudden it starts up and no probs the rest of the day.I have not had any probs of not starting or loosing volts today(knock on wood) so anyone know what would cause it to loose volts then jump back to full volts all by it self im lost on what it could be... maybe voltage regulator going out? i dont know.... any help or ideas would be greatly appreciated ... and everything is tight batt cables are tight and clean and i found no loose wires any where...

 

[96_XJ]

I was having the same prob, but only I could not see my volts.(lame dummy lights) After playing with wires and what not, it would start. I started to think something was up with my starter. Had it rebuilt in a hour and the thing has not done it again. This happend on my 96 XJ. Cant say for sure if it would be same for yours, I was not able to see what my volts were doing. Have you check to make sure the bolts that hold the wires to the starter and good and snug?

 

[JeeperG]

I am probably wrong here but make sure that the Battery cables are really tight on the battery. (should not be able to move them at all) My YJ had problems cause of that. Good luck though cause wiring problems are the worst.

 

[ranman]

Sounds like a grounding problem, make sure the wire that comes from the neg. side of your battery that goes to the frame of the vehicle is tight, not corroded and is clean from paint and so on.
Good Luck

 

[01XJ]

ok now the damn thing has a new problem....it still looses volts acts like it has a dead batt..but if you keep trying it over and over it will eventually start and everything is fine....well the new problem is when it does this little no start thing now when it starts up it wont idle at all you let up off of the gas it dies start it back up just fine but still wont idle so you got to drive it a few miles of using brake and gas at same time so it dont die then you can turn it off and start it again and it is just fine will idle and everthing i have checked every damn wire i can fine and everthing is tight and clean ...now this idleing problem that goes away after a few miles of driving (got to turn it off and re-start to fix it) anyone have any more ideas of WTF is going on? or what else i could check

 

[XJScott]

ok now the damn thing has a new problem....it still looses volts acts like it has a dead batt..but if you keep trying it over and over it will eventually start and everything is fine....well the new problem is when it does this little no start thing now when it starts up it wont idle at all you let up off of the gas it dies start it back up just fine but still wont idle so you got to drive it a few miles of using brake and gas at same time so it dont die then you can turn it off and start it again and it is just fine will idle and everthing i have checked every damn wire i can fine and everthing is tight and clean ...now this idleing problem that goes away after a few miles of driving (got to turn it off and re-start to fix it) anyone have any more ideas of WTF is going on? or what else i could check

Have you had the Charging system and battery checked?
Mine was doing the same thing until i replaced the battery. now it starts first time everytime!
If the system has less than 9 volts, It will not even power up the computer. whe you are driving around, the alternator is keeping the voltage up to run everything but when you come to a red light/stop sign, the RPM's go down and it does not pump out enough juice to keep the computer alive.
If you have another car, try trading batteries. thats how I found out mine was toast.
Good Luck...

 

[mbryson]

I'm betting you've got a bad connection (take the terminals off the battery/starter/ground location to check and clean), but if you've checked all that you've said you have, I'd vote for the bad battery.