One wire alt. operation

I have a 1998 trans am with the LS1 motor. My question is how does the one wire altenator work? What monitors the amount of charge that the battery needs? I have a discharge problem replaced the altenator and new battery. When the car sits over night works fine problem only occurs when car has been running for a while. Very odd. By the way , I am a electrician so I have checked and double checked for loose connections.:banghead:

Computer monitors battery voltage and regulates the alternator. Sounds like you have either a loose belt or a defective alternator if its draining while its running. Have a parts store check the alternator for you. It's where I would start.

I have a 99 with a v6. As far as I know the voltage regulators in GM products are in the alternator. It is in mine. When my original alternator went bad I got a rebuilt one from NAPA. The original tested bad on their tester. The replacement didn't put out a charge. With everything contained in the alternator I figured that could only mean I got a bad replacement. It tested good on their tester. I had them get me a different one anyway. The second one worked. Shows you can't always trust their testers.

I have a 99 with a v6. As far as I know the voltage regulators in GM products are in the alternator. It is in mine. When my original alternator went bad I got a rebuilt one from NAPA. The original tested bad on their tester. The replacement didn't put out a charge. With everything contained in the alternator I figured that could only mean I got a bad replacement. It tested good on their tester. I had them get me a different one anyway. The second one worked. Shows you can't always trust their testers.

The best way to test a alternator is on the car.
I do not want to start a Napa war but Napa has went down hill on quality parts along with a lot of other after market rebuilt stuff.
Next time consider a Dealer rebuilt alternator.
They only hurt one time.:grinyes: :grinno:
Your cheaper after market stuff will bite you many times.

Computer monitors battery voltage and regulates the alternator.

eh? :screwy:

99 'bird is on the money, voltage regulator, internally mounted in the alternator. This holds true on all charging systems I've ever dealt with, that they all use a regulator, only differences are if it is internal or external mount like Ford did for a long time.

:thumbsup:

I have a 1998 trans am with the LS1 motor. My question is how does the one wire altenator work? What monitors the amount of charge that the battery needs? I have a discharge problem replaced the altenator and new battery. When the car sits over night works fine problem only occurs when car has been running for a while. Very odd. By the way , I am a electrician so I have checked and double checked for loose connections.:banghead:

As said they are computer controlled on charging.
Put a volt meter on it when it is running about 2K rpm with every thing turned on.
Your volt meter should hold over battery voltage of 13.6 volts.
About or over 14 volts or a little more it is carrying the load and charging.

What did I miss here, when did the PCM take over the charging system?

What did I miss here, when did the PCM take over the charging system?

The PCM are taking over control of everything.:lol2:
Cry done it years back in the 80's.
And like monkey see's monkey does.
Now most all of the car makers are now doing it.
And you had to replace the pcm to get it to charge when it went out.
MT

From the 93-98 Camaro/Firebird repair guide overview:

"The automobile charging system provides electrical power for operation of the vehicle's ignition system, starting system and all electrical accessories. The battery serves as an electrical surge or storage tank, storing (in chemical form) the energy originally produced by the engine driven generator. The system also provides a means of regulating output to protect the battery from being overcharged and to avoid excessive voltage to the accessories...... "

......."The voltage regulating function is performed by a regulator. The regulator is often built in to the alternator; this system is termed an integrated or internal regulator".

Now, I do not know about Chrylser and wouldnot doubt it either that they did start doing em that way through a ECu, but I have et to see a one wire GM charging system controlled by the ECM/PCM.

From the 93-98 Camaro/Firebird repair guide overview:

The automobile charging system provides electrical power for operation of the vehicle's ignition system, starting system and all electrical accessories. The battery serves as an electrical surge or storage tank, storing (in chemical form) the energy originally produced by the engine driven generator. The system also provides a means of regulating output to protect the battery from being overcharged and to avoid excessive voltage to the accessories......

.......The voltage regulating function is performed by a regulator. The regulator is often built in to the alternator; this system is termed an integrated or internal regulator.

Now, I do not know about Chrylser and wouldnot doubt it either that they did start doing em that way through a ECu, but I have et to see a one wire GM charging system controlled by the ECM/PCM.


It is not done on all of them but on that one.
But notice on that one the one wire is routed threw the PCM

Here it is. :grinyes: :lol2:

http://members.troublecodes.net/crunch/98firebirdaltt.pdf

That does nothing more than throw the "check gauge" light on if you're not paying attention :dunno:

That does nothing more than throw the "check gauge" light on if you're not paying attention :dunno:

The V6 and V8 is a little different but on the V6 the L terminal sense voltage all has to go threw the PCM.

http://members.troublecodes.net/crunch/98v6altcheck.pdf

If the pcm does not allow voltage on L sense terminal it will no charge.

It might be interesting to to disconnect the L sense wire on the V6 after the engine is running and see what the alternator does.
That would tell us for sure if the pcm has full control or just starts the alternator charging.
MT

That does nothing more than throw the "check gauge" light on if you're not paying attention :dunno:


A little more info on it.

From mr. Mitchell on demand
http://members.troublecodes.net/crunch/98v6altcontro.pdf


From a old alternator engineer.
http://www.batauto.com/Forums/index.php/topic,584.0.html

Ok, but it still has a regulator, and the question of the thread is how does a one wire alternator work, and this a V8.

I get the point, and learned something new. Thanks :thumbsup:

Thats stupid.

Thanks for all the info. Ok For one the alt. is a brand new GM replacement and since I have the same problem it's not the alt. or internal reg. Once my computer would not send the ground signal to the start relay after the security check so I had to make a jumper to ground to get the car started. Then at one time the horn should blow twice when the alarm is set but would only blow once. That problem cured itself. Maybe bad computer? Bad connection on computer?:banghead:

The PCM is not the issue here at all.All in this thread are right and yet somehow all are wrong,go figure.In a basic term,the more the system draws,the more the alt will produce,if it is able to only produse 25 amps,that's all your gettin.Being a 98 it is prob a large output alt in a small case alt,bad plan on GM.

I'd check all grounding straps and cables before changing the computer out. I've heard of more weird problems than I can count from bad ground.