my s13 is acting dumb(starts when it wants to)

[musk'r]

i have a s13 coupe with stock ka24de i replaced it like191 miles ago as well as a clutch,flywheel did a regular tune up and 2 days ago i replace my transmission cuz my 5th gear went out..my car was origanially auto and now a 5speed.thee previous owner did the 5speed swap.so i drove to school and back then decided to go to the store and my car wouldnt start.so i jumped it thinking i left some light on.i go to the store as im leaving the store again the car wont start so i jump it again then all of a sudden it just turns off i jump it again as im removing the positive cable the car just dies....then today i turned it on it satrted with out a problem i was like wtf..any ideas what can it be thnx..sorry for the eassy i just wrote

[ShaunakaRichard]

That definitely sounds like a battery/charging system problem. The fact that jumping it made it start immediately points to a low battery. If you have a voltmeter start the car, jumping it if you have to. Put the meter on the battery and see what the voltage is. Should be over 13 volts when running. If its not than your alternator is probably bad. If its fine than your battery is probably going bad. You can have your battery load tested to see if its within spec.

It could really be either one based on your description. If you don't have a voltmeter they are cheap and really handy thing to have. They're really useful.

[Doya]

Definitely sounds like your alternator isn't keeping your battery charged. Test the volts coming from it.

[moso]

inside you alternater there is an electrical unit called the "diode trio" it supplies field current to the alternator when the car is running. as those diodes go bad the alternator gets less and less running field current causing it to charge the battery less and less. it sounds like yours is on its last diode which is causing the problem your having. i would suggest replacing the alternator even if it tests ok as it may still put of current durring low load like durring the day with the lights off and the car parked, or off the car as it would be when you have it tested.

[musk'r]

cool thxs for the info i check'd the voltage it was slightly over 13.it was like 13.3 something like that...yea true i should just replace my alternator cuz my battery is not even a year old so i dought its the battery..thanx again ill keep post'd see what happens then..