HELP my car only starts with a boost

[mtbr64]

so i get back into my car to turn it off and to my surprise it doesn't turn over.
so i boosted it and it runs so i drive for a bit then at a stoplight when im in neutral it dies out. so i boost it again and its fine everything is great so i turn the car off again and it won't start.
so the car only starts with a boost
dies after i drive it and come to stop without keeping the rev's up
what could it be?
i don't think its the battery because my dome light still turns on.
help me guys im in a tuff spot.

[jtt220]

just bacause your dome light comes on doesn't mean your battery is holding a charge. Go to sears and have them check it out. They can tell you if it is your battery or alternator.

[mjjstang]

like Ive said before. starting the car takes a hell of a lot of power. lights can still be on and you wont be able to start it. Id say try a new battery, if its not that. then its probably the alt. or you could be having a leak somewhere, youll have to tool around w a volt meter to figure that out but id deffinitely try another battery in the mean time.

[mtbr64]

ok coo thnx for that fast reply man i appreciate it
anybody got any other suggestions?

[RiceEata]

what do you mean by boosted it?
jump starting?

use a voltage tester and test your battery and alternator.

[idlafie]

Take a voltmeter & place the test leads on the appropriate terminals. Measure the current at the battery posts with the engine running. You should be getting approximately 14 volts. If you do then the alternator is working fine. With the engine off check the battery again. Place the test leads on the battery posts. You should be getting 12 volts. If not, then check your battery. Some batteries require distilled water to maintain the electrochemical reaction required to charge a battery.
http://www.edmunds.com/ownership/techcenter/articles/43835/article.html
If the distilled water falls below a certain level for a sufficient amount of time then the battery starts to lose it's ability to maintain a charge. Once that happens, then it's time to replace the battery. Check to see if your battery is a "low-maintenance" battery - which means you have to add distilled water every so often or a "maintenance-free" battery - which means you don't have to add any water at all. The "low-maintenance" battery will have two big tabs on the top by the battery post that can be pried off with a screwdriver. Pry the top off & you will see six "cells" where you can add water. The "maintenance-free" battery doesn't have any tabs to pry off - all you will see is a blue or green "eyelet" which tells you the charge state of the battery. Most stock original 240SX batteries are the "low-maintenance" batteries which require distilled water every so often.
Now if your problem ISN"T your battery, then check for a loose ground wire or loose battery wire. Trace the negative ground on your battery back to the battery itself. Make sure all the wire connections at the ground points are good. Do the same for the positive battery wire running from the battery to the alternator. Also check the fan belts. Make sure the fan belt going to the alternator is not loose. A loose belt will not help the alternator charge the battery properly.
Chances are it could be either a loose fanbelt OR a a loose battery wire somewhere. Check to make sure everything is tightened down properly & making proper contact. If it were your alternator your car would have died by now taking the battery with it. Jumpstarting would help get it started, but won't help to keep the car running for long after you've disconnected the jumper cables.
Anyhow hope this helps.
Good luck with the repair.
ID

[mtbr64]

thnx idlafie very informative ill go chek it out now

[KOUKI KA-T]

A voltmeter?? That's a joke, it won't tell you shit.... Test it with a real battery tester that tests AMPS.... A voltmeter is completely useless for testing a car battery.

[idlafie]

A voltmeter?? That's a joke, it won't tell you shit.... Test it with a real battery tester that tests AMPS.... A voltmeter is completely useless for testing a car battery.

I beg to differ. A voltmeter is an EASY, cheap and simple way of testing if the alternator is supplying voltage to the battery and if the battery has a sufficienct amount of charge to start the car. A battery tester that tests AMPS is a hell of a lot more expensive than a voltmeter. A voltmeter is a good simple diagnostic tool for troubleshooting. When you go to start the car & see the voltage drop from 12 volts to something like 8-10 volts, then you know you have a problem with your battery.Yes you can go out and buy a battery tester OR you can pull your battery & take it to an automotive shop to test your battery ON an amp meter, but it's easier just to check it with a voltmeter without having to remove the battery from the car. Given a choice what would you do? Would you do it the simple way or the hard way??
ID

[KOUKI KA-T]

I beg to differ. A voltmeter is an EASY, cheap and simple way of testing if the alternator is supplying voltage to the battery and if the battery has a sufficienct amount of charge to start the car. A battery tester that tests AMPS is a hell of a lot more expensive than a voltmeter. A voltmeter is a good simple diagnostic tool for troubleshooting. When you go to start the car & see the voltage drop from 12 volts to something like 8-10 volts, then you know you have a problem with your battery.Yes you can go out and buy a battery tester OR you can pull your battery & take it to an automotive shop to test your battery ON an amp meter, but it's easier just to check it with a voltmeter without having to remove the battery from the car. Given a choice what would you do? Would you do it the simple way or the hard way??
ID

Voltage has absolutely nothing to do with starting the car, that's why. It's amps. A battery that is so dead the dome light won't even turn on can and often will still show around 12 volts if you test it with a voltmeter. You cannot determine whether a battery is dead or not with a voltmeter.

Edit: I can't read.

[PSI240SX]

I think the main point in his argument was using the voltmeter to determine whether or not the alternator is charging. If its charging then there is only one other place to look.... THE BATTERY. Jeez stop being an ass.

[KOUKI KA-T]

Hmm, actually you are right. I was overlooking his point of testing the alternator. My impersonation of a sphincter is over now...

[PSI240SX]

Bravo! You did have good points as well, it's just that I have only ever used a voltmeter to determine the culprit in situations like these, and they always work out well for me.

Another easy way to test, even if you dont have a voltmeter is to disconnect the battery cable while the car is running, if it continues to run, your alternator is working fine, and your battery is toast, if it shuts off, the alternator is bad.