theory

iTrader: (5)

I got an 87 N/A 3 days ago. It was a base GX that was converted to a GXL by the previous owner, kept in great shape.

So I take ownership of the car, and that evening the car has trouble starting on 4 ocassions. It would crank and crank but not ignite. Then after about 10 minutes of efforts it would start up, this happened 4 times that night. I figured it could have been a hot start problem as it was driven alot that day to transport the car from the previous owner to myself.

Then the next day it started up fine, no problems.

SO today comes around and again it starts up no problem.

However after driving it for about 45mins I notice that the Battery gauge was around 10V. It kept getting a little bit lower everytime I checked. SO I start on my way home as soon as possible.

Everytime I had to come to a stop the Battery guage would drop significantly, and then raise a little once I got going again.

Finally just as I reach home it dies... luckily.

The car wouldn't not even crank after this.

I know there is a crappy "surestart" battery in there right now, I was going to replace this soon anyways, and I'm going to get it tested to see if it holds a charge tomorrow... However any input would be greatly appreciated.

DO you think it is the battery or the alternator?

Thank you.

NMJ87T2

iTrader: (8)

Charge the battery or get another battery for this test. Crank the car and then pull off the + battery cable. If the car dies the alternator is bad. If it continues to run you had a bad battery.

gscully

sounds like the alt to me if the battery was bad the voltage should still be up while running it just won't charge up. You could charge the battery then go to canadian tire to get them to run a load test on the battery they do it for free.

lukerx7

its most likely ur alt because while the car is running it runs off the alt but since yours isnt working its running off the battery and killing it... i had the same problem with my car and it was the alt

spot_skater

Get a DVOM or DMM of some sort, check the voltage output of the altnernator. Put the positive lead on the B+ terminal of the alternator, and one on battery ground. It should be somewhere around 13.5-14.6v. If it's less, or doesn't read anything, most likely your alternator is fucked.

Also check the voltage output of your battery. If it's somewhere around 12v, 12.6v is best, then you're in decent shape.

hanman

It's the alt.

DerangedHermit

Your alternator/wiring is fucked. While driving, the battery should have NO part of providing electricity to your car if your alternator is running correctly.

Do the tests in the FSM (and I think someone mentioned one of them) or get it tested and see if it really is your alternator. If it isn't, then I would say it's a wiring problem.

Did it drop while you had your brakes on? My old alternator did that and that's a good sign it's screwed.

elnots

I was taught by master technicians thatremoving the battery cable while running is one of the worst things you can do for your electrical system..

Removing the battery cable, can and will cause your electrical system to feedback on itself somewhere causing a short or even blowing your ecu. Most of the time blowing your ecu is what happens.

It's playing russian roulette with your car when all you need is a god damned multimeter!

DerangedHermit

+20000293092

I think it would be smarter to just replace the engine. I mean... he's having an electrical problem so why not?

(Sarcasm if you didn't tell... don't actually replace your engine unless you want to "donate" your old one to me. In that case, by all means do it.)

theory

iTrader: (5)

Yeah it dropped once I applied my brakes. I was almost certain it was the alternator myself, but I wasn't 100% sure.

fc3snicko04

Yea i agree with elnots do not remove the battery cable while running your vehicle trust me i am a technician

T2 FC3S

Yup Alt. , I had a similar problem recently.

theory

iTrader: (5)

I'm taking the alt to go get checked, but ordered a new one anyways, as well as replacing the battery. Might as well start off fresh. Thanks guys.

xzyras

Why not?

Edit: oh, never mind I read farther back

Needa13b

12.66 V = 100% Charged
12.45 V ~ 75%
12.25 V ~ 50%
12.00 V ~ 25%
11.75 V ~ 0%

Those voltage figures just tell you the percentage of the battery's capacity. The OCV (open circuit voltage) measurement should be taken with surface charge removed, (let the battery sit 24hrs, or leave the High beams on for a few minutes.) Car should not be running.

You can have a fully charged battery measuring 12.66V, that doesn't have the capacity to run a wrist watch.