My 02 with the 5.9 has a problem where it won't start sometimes. If I let the doors open or lights on for more than a few seconds it will crank the starter over very slowly and the die completely. I checked the battery voltsge: 12.6V not running, no load. With lights on it drops quickly from 12.6 to 11 in about 60 seconds. Just a second with a jump and it starts up fine. Voltage running is 13.7V ( sounds low). Do you think its just a bad battery or a weal alt not supplying enough output to keep the battery up ?

Also about half the time after a jump you must keep some amount of throttle just to keep it running. Is this a problem elsewhere or just the computer relearning? Thanks, Jon

 

sounds to me like a bad battery, but in your case i would also look into replacing the alternator too since the voltage while running (alternator produced voltage) should be around 14.3-14.16 to charge the battery.

my recommendation is new battery and alternator

 

If the battery is under 12 volts then the diode bridge will not get enough power to transfer AC into DC current there for your system can't run and the motor stumbles and tries to die.

Yes it sounds like a bad battery. 13.7 output isn't that bad on the alternator but it does sound like it's getting worn.


Personally I would go get a Auto Zone Duralast Gold series battery (the biggest one that fits). Also it could be your starter starting to go but I doubt it.

 

+2 on the battery, get the alt checked out as well. I'm not so sure the starter is the culprit cause if it is, wouldn't it make a clicking sound but not turn over?

 

im willing to bet its the battery, probaly an good idea to replace it anyhow as if its stocker battery, its 8yrs old! i just replaced the battery on my 02, i went to les schwab and had to pay 100 for there top of the line extreme battery, not sure if i really needed to but hey it has an 8yr warrenty though so its good.

 

I'll replace the battery tonight and see how it goes. Thanks to everyone for your help.

 

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