battery or alternator ?

F

finalgathering

New Member

Feb 7, 2003

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Aug 3, 2005

#1

• Aug 3, 2005

• #1

My buddy's 88LX starts when boosted but dies as soon as the cables are removed. We don't know if it's because of the batery or the alternator but my hunch is that it's the alternator because most cars will continue to idle even if the "battery" is removed . Am I correct? . If so any recomendations? He doesn't really have an amp and stuff but may be concidering underdrives.

 

5.0 con-vert

No soup for you, Joe Rogan!!!

Jun 7, 2005

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Boca Raton, FL

Aug 3, 2005

#2

• Aug 3, 2005

• #2

how long do you leave the cables on for after it starts? The alternator doesn't appreciate it much when you expect it to charge a fully dead battery. Chances are it is the alternator now, if not before, but you might as well replace them both at this point just to avoid further problems

 

jrichker

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Aug 3, 2005

#3

• Aug 3, 2005

• #3

Running an alternator with the battery disconnected is asking for electrical spikes that can fry the computer & other electrical equipment. Alternators for cars are not designed to run without a battery, and I would be suprized to see one run without the battery connected.

At this point in time, swap a good battery into the car and see if if will continue to put out 14 volts at 1000 RPM. If it does, then the alternator is probably OK.

 

HISSIN50

"How long does it take to get help in here?

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#4

• Aug 3, 2005

• #4

JR is spot-on!

One could also remove the battery and alt and have them bench/load tested at the parts store.

Good luck.

 

88stang88

5 Year Member

Apr 28, 2005

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St. Louis,MO

Aug 3, 2005

#5

• Aug 3, 2005

• #5

alternator is probably the problem,could be bad....

 

kornchild4life

New Member

Mar 30, 2005

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islip, ny

Aug 3, 2005

#6

• Aug 3, 2005

• #6

A battery is just there to start the car and run the electrial crap, once the car is running you should be able to disconnect the battary and still have it running.. Try putting in a good battery and while the car is running, take a volt meter and see if your getting a reading from like 12.0-14.something depending on the alt. he has in it. If you dont get those something between those numbers then the alt. isn't charging and is shoot. Hope this helps

 

HISSIN50

"How long does it take to get help in here?

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#7

• Aug 3, 2005

• #7

kornchild4life said:

A battery is just there to start the car and run the electrial crap, once the car is running you should be able to disconnect the battary and still have it running.. Try putting in a good battery and while the car is running, take a volt meter and see if your getting a reading from like 12.0-14.something depending on the alt. he has in it. If you dont get those something between those numbers then the alt. isn't charging and is shoot. Hope this helps

Click to expand...

In the old days before computer controlled cars, people would do stuff like this. I would not these days. I know about 1/10000th as much as JR, but it seems to me that the battery acts as a 'damper' for the alternator's output, helping to quell spikes and suck (alts can put out some nice spikes).

I would never run an EFI car with no battery, nor would I remove a cable with the car running. Why take a chance - there is no need to.

 

88-GT

Member

Oct 8, 2004

183

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Aug 3, 2005

#8

• Aug 3, 2005

• #8

Yea id he is thinking about pulleys and a stereo itd be best to just upgrade the system right off the bat. Do the 3G, its SOOOO simple and well worth it. I did it my first time in under 2 hours and have never looked back. One of my more favorite mods for the price and time invested. And while he is at it tell him to go get a good strong battery and then finish it up with the big 3. He'll never regret it.

 

B

BaXTeR3221

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Jan 12, 2004

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Orange County, NY

Aug 3, 2005

#9

• Aug 3, 2005

• #9

I've disconnected a battery a couple times with the car running. I'm sure it wasn't the best idea, but it was the easiest way to charge the battery(start car, swap, and go for a drive to charge the dead one). That being said, i had the same problem you do about a year ago. Jumped the car and once the cables were off, it would die. Turned out that the previous owner had rigged up the wiring and it was lose. I fixed it with one the plugs your supposed to use and everything was golden.