Car Starts After Jump but Wont Start Again

Car won't get-go unless jumped. How to tell if information technology's the battery or alternator?

• Thread starter daveymark
• Start date November 8, 2005

• #two

Put a DMM on the bombardment while information technology'south running and encounter what the voltage is.

• #3

test the battery on a tester, or take it to a shop

• #4

The alternator doesn't practice anything until the motor is running.

• #five

Put a meter on the Altenator to see if it has any output can also be checked by your guages in the vehicle unless yous accept idiot lights..

Ausm

• #6

the old method of testing the alternator was to disconnect the neg concluding of the battery while the care is running. If information technology dies, the alt is the problem.

• #7

anyone have an idea if volition autozone test it for gratuitous? I know they do the diagnostic lawmaking checker for free

• #8

if your alternator is dead, your battery won't charge and your car will prolly die in curt order. If it runs for hours after jumping, information technology's prolly the battery.

I had the alternator go in my old volvo at school. I had to have a friend bound me 3 times to get me to the garage, at night. Boy that was fun. I remember being suprised at how quickly the auto died, especially with lights on.

• #9

If your auto needs a bound so it is your battery

If it was your alternater your car would dice in the middle of driving.

Peace

• #10

I drove 50 miles after I jumped it. It didn't dice, I arrived at my destination. Then this morning time it wouldn't start once again. Does that mean it's probably the battery?

Apr iii, 2001

53,216

five,590

126

• #11

Originally posted by: daveymark
I drove 50 miles afterwards I jumped it. It didn't die, I arrived at my destination. Then this morning time it wouldn't start again. Does that mean it's probably the battery?

Yep. 50 miles should take put a bit of a accuse into it, so it's probably non property information technology any more.

• #12

Sounds like the battery to me...

• #13

Originally posted by: daveymark
anyone have an idea if will autozone examination it for complimentary? I know they do the diagnostic code checker for free

Yes, AutoZone will practice a load exam on the battery and let you know if it'due south dead. They do it for gratuitous. Information technology takes just a few minutes.

They'll also test your alternator for free if you desire to take it out. Aforementioned deal with the starter.

• #fourteen

Originally posted past: Heisenberg
Put a DMM on the battery while it'southward running and see what the voltage is.

To be a little more articulate... you accept a 12V battery in your car. If y'all disconnect the battery and measure the voltage, it might read something like 11.5V.

If you lot turn on the engine, the alternator will charge the battery and you'll read something higher... perchance 14V. If the alternator is dead, y'all won't read "something higher".

• #15

Bombardment.....Or depeding on what blazon of vehicle, it could be something in between that's non charging it. I would offset with the battery first...

• #16

Originally posted by: Aimster
If it was your alternater your machine would die in the middle of driving.

Non necessarily true. My Honda had a bad alternator, and it would bleed the battery , and I would have to jump it.

Jun 5, 2000

36,413

616

126

• #17

Originally posted past: robphelan
the old method of testing the alternator was to disconnect the neg terminal of the battery while the care is running. If it dies, the alt is the problem.

yip, i accept used this method a few times and has always worked and was correct.

• #18

Originally posted by: Heisenberg
Put a DMM on the bombardment while it'due south running and see what the voltage is.

True.
A bad battery will drop to < 10 Volts under load.

• #19

Originally posted by: robphelan
the old method of testing the alternator was to disconnect the neg final of the bombardment while the care is running. If it dies, the alt is the problem.

That must be before stuff like Fuel Injection, ECU and other electronics.
The car will die no matter what if you do that.

• #xx

Originally posted by: robphelan
the old method of testing the alternator was to disconnect the neg terminal of the battery while the care is running. If information technology dies, the alt is the problem.

Exaclty what i was going to say. Just make sure the machine hasnt been runnign for a while. Some batteries are just weak, only will take some charge. And then, merely jump information technology, then disconnect the battery immediately.

[edit] meant battery ... [/edit]

October twenty, 2003

21,753

4,103

126

• #21

Alternators don't always fail completely right away, often they stop charging gradually, so the but way to be certain is to examination the charging output, nonetheless if your battery is more the three-4 years old it may be dead also... exist really careful if y'all become to Sears or somplace like that though because they'll rip you right off and take you replacing the battery & the alternator wether you demand it or not.. best bet is to examination yourself or remove the alternator and take information technology to Autozone as has been suggested.

• #22

Take out the battery and take it to AutoZone.

If not battery,

Have out the alternator and accept it to AutoZone.

Jun 13, 2000

26,151

one,583

126

• #23

What year is the car? Take you ever inverse your battery? Unremarkably batteries have 5 yr warranties on them. You can expect a battery to last at to the lowest degree that long....some volition final 3-four years....information technology's a mixed pocketbook.

AZ volition bank check your battery. The alternator tin't charge a bad battery.

If the alternator goes bad, it will sometimes draw current from the battery even when the car is off... (bad diode tin can make the alternator (generator) turn into a motor) So first with the bombardment and don't listen to whatever mechanics trying to talk you into replacing the alternator yet.....

• #24

Originally posted past: Aimster
If your automobile needs a spring and then it is your bombardment

If it was your alternater your car would die in the middle of driving.

Peace

Unless a bad alternator cause the battery to die.

edit: You need to accept the alternator tested, not the battery. You know the bombardment'due south expressionless, it'south a thing of why. The fact it isn't charging doesn't hateful jack. Information technology could mean the alternator isn't charging, or the battery isn't holding a charge.

edit2: Chances are if the alternator is bad, the battery needs to be replaced, but not always.

May 27, 2002

12,638

197

106

• #25

Have a drive...
Advanced auto will test your battery, starter, ignition, and alternator for free...

• Advertising
• Cookies Policies
• Privacy
• Term & Conditions
• About us

• This site uses cookies to help personalise content, tailor your experience and to keep you lot logged in if y'all register.
  By continuing to use this site, you are consenting to our apply of cookies.

newmanancen1954.blogspot.com

Source: https://forums.anandtech.com/threads/car-wont-start-unless-jumped-how-to-tell-if-its-the-battery-or-alternator.1737470/

Share this post