strange issue, indeed

jackmalone2001 · #1 01-30-2005, 05:38 PM

Hi to all, it has been a while but I guess that is good news.

the backstory:
I have a 1994 v6 Camaro involved in a flood, took her apart and replaced a buttload of pieces, put her back together and hit the road.

Two things I have not replaced were the battery and the alternator.

Driving down the highway today, I hit my rear defogger switch and it seemed for a second like my girl wanted to stall. (Of coarse at 75 that is kind of hard.) there were no other electrical componants on at the time. (Other than the engine, and engine management stuff.)

So, my question is:

Is there any way to determine which needs to be replaced, battery or the alternator, in a situation like the one mentioned above.

Thanks for any help or advice you have!

Jack

FormulaLT1 · #2 01-30-2005, 07:39 PM

Start the car, run it for like 3 minutes. turn on all the power accesorys and then pull the positive battery terminal. If it stalls. then its the alternator. If it stumbles for a sec then volts come back up or doesn't stumble at all then alternator is fine and maybe you could use a battery. Also welcome back.

John

Savage Messiah · #3 01-30-2005, 08:02 PM

Seeing how you didnt replace either one, I'd say replace both anyway

Morley · #4 01-30-2005, 10:16 PM

It is never a good idea to remove the battery cables on a computer controlled car while it is running.

FormulaLT1 · #5 01-30-2005, 10:16 PM

who told you that?

Genopsyde · #6 01-30-2005, 10:25 PM

Honestly, I don't think it's the battery or the alternator, if everything was fine until you turned the rear defog on then perhaps your problem lies within that.

jackmalone2001 · #7 02-01-2005, 04:51 PM

Formulalt1--interesting idea, but I have heard it said in this forum NOT to disconnect the battery when the car is running---but you say that if I do this it is the alternator, and NOT the battery? 97camarors posted "replace them both", good idea but if I had that kind of scratch, I wouldn't be begging for help! So, other than removing the positive battery cable while the car is running, there is no way to determine if the battery or the alternator is defective?

FormulaLT1 · #8 02-01-2005, 04:56 PM

Contrary to what some guy told some guy. Your not going to short anything out or blow up your car from pulling the positive battery terminal. It is infact a testing method done in almost every dealership in the world. Plus if you have a healthy charging system your car won't even blink. If it stalls your car alternator isn't giving enough juice to keep your car running let alone charge your battery like it should be doing.

John

Xenostalgia · #9 02-01-2005, 08:19 PM

Dude...whoa...
1: If your car turned into a submarine as the pictures state you should check all the wiring for any rust/corrosion and or breaks.
2: If there is any pulley connected to the engine for that maybe you should check that too.

I dunno if theri s a pully. Otherwise take it into a mechanic and ask wtf.

Morley · #10 02-02-2005, 02:07 AM

Quote:

Originally Posted by FormulaLT1

who told you that?

Ummm, lets see..GM, My owners manual, every mechanic I've talked to...pretty much everyone.

Also, if you do pull the battery cable the car will shutoff no matter if the alt/battery are good, bad or whatever. You have just removed power to the ECM, which is tapped off the positive cable on a pigtail, no ECM= no injectors, no sensors & no workie.

The old pull the battery cable tricked worked great, until the advent of F/I.

jackmalone2001 · #11 02-02-2005, 01:31 PM

seems like I started quite the debate! Sorry! Xeno mentions a pully, I am not clear on what he's talking about. Also says to check the wiring, good advice. Thanks guys--

FormulaLT1 · #12 02-02-2005, 01:48 PM

Quote:

Originally Posted by Morley

Also, if you do pull the battery cable the car will shutoff no matter if the alt/battery are good, bad or whatever. You have just removed power to the ECM, which is tapped off the positive cable on a pigtail, no ECM= no injectors, no sensors & no workie..

Dude I have tested this method on my FUEL INJECTED car plenty of times and if your going to correct me with bogus info again. I would prefer you not reply at all. The alternator is what charges your coil, your power accesory's and your PCM. Follow your positive power terminal. If you disconnect the Ground then yes the car would die or stall but the postive terminal has a 3 way way wire split. One goes to the battery, one to the alternator and the other is connect ot a terminal that runs to the PCM amongst a few. Also youn must be reading something incorrectly cause my uncle had worked at a dealer for about 20 years before he bought his own shop and he is a Automotive electrical engineer specialist and he is the one who taught me how to test this way. So if he is wrong then the world makes a little less sense to me.

Chevyracincamaro · #13 02-02-2005, 03:42 PM

y dont you just do it the easy way and take your car down to advace auto and have them test everything for free with their diagnostic tool...

Xenostalgia · #14 02-03-2005, 03:14 PM

Ja... Uh pulleys the lil spinner discs that turn the belts on the front of the crank on the front of your engine. e.e that kinda thing... uh yah.... (not good with technical details)

Morley · #15 02-03-2005, 07:59 PM

Quote:

Originally Posted by FormulaLT1

Dude

First off, I am not a "dude".
secondly, trace the wire coming off the battery that has a nice little fuse in it, that powers the ECM and fuel pump. pull that cable and it all shuts down, period. I have been working on cars for 30+ years now and know them pretty well, I have been working on TPI's for the entire 20 years they have been around and know how they do and don't work.
You don't like my advice..don't take it. Bogus? Hardly.

Oh, and another reason not to remove the battery cable from a running car is that the ECM's are VERY intolerant of voltage spikes and have no way to protect themselves. But hey, they only cost $110+, so take a chance

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