For u who know it all...
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Teching In
Joined: Oct 2010
Posts: 31
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From: Oklahoma City, Oklahoma
For u who know it all... I have a 2000 z28 b4c and i cant get my alternator to charge my battery. I've got a new alternator, new battery and new battery cable. I've checked every ground and it's getting power to everything, all the fuses are fine. I have also replaced the excitor plug that plugs into the alternator. I don't know what else it could be. I've been stumped on this for a week. I've gone to gm goodwrench service and they don't know what it could be either. I was told to hook it up to a Genesis machine, but am trying to avoid paying out the rear to have it tested. Plz help me out with this if you have any ideas cause I'm stumped.
One from left field, be sure your speedometer cluster is securely plugged in. with it being loose it stops the charge of the alternator to attempt to prevent mileage tampering.
Thread Starter
Teching In
Joined: Oct 2010
Posts: 31
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From: Oklahoma City, Oklahoma
The battery is only a week old. the voltage from the battery terminal with the engine running is 11.5 roughly. and the instrument cluster has never been removed or ben hit or in an accident that would let it come loose.
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TECH Addict
Joined: Aug 2002
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From: N. FL
I'm with them... Try your alternator again. You may have gotten a bad one. It should be putting out at least 12.7v bare minimum and standard working units put out roughly 13.8v.
You may wanna have it tested where you bought it, then replace it with another. It's surely bad, be it the voltage regulator or whatever.
You may wanna have it tested where you bought it, then replace it with another. It's surely bad, be it the voltage regulator or whatever.
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It sounds like you've already covered all the basics. The alternator will not charge unless it's seeing the proper signal from the PCM.
Using an Ohm meter or self powered test light, check for continuity on the wire between the exiter terminal (in the plug at the alternator) and the pin at the PCM. In the case of a 2000 F-Body, it's pin number 15 on the C2 (red) connector. Disconnect the battery when unplugging either plug from the PCM.
If this wire reads good, I would swap out the PCM and then see if you have 13 volts or more at the battery while running.
Here's an odd question: When you replaced the plug at the alternator, did you splice to the one correct pin?
http://www.ls2.com/boggs/torques/00pinpcm.htm
And:
Using an Ohm meter or self powered test light, check for continuity on the wire between the exiter terminal (in the plug at the alternator) and the pin at the PCM. In the case of a 2000 F-Body, it's pin number 15 on the C2 (red) connector. Disconnect the battery when unplugging either plug from the PCM.
If this wire reads good, I would swap out the PCM and then see if you have 13 volts or more at the battery while running.
Here's an odd question: When you replaced the plug at the alternator, did you splice to the one correct pin?
http://www.ls2.com/boggs/torques/00pinpcm.htm
And:
Thread Starter
Teching In
Joined: Oct 2010
Posts: 31
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From: Oklahoma City, Oklahoma
I had the alternator checked and tested 10 times and was fine everytime. I ended up taking the car to the dealership. They told me that the pcm was bad. I gave in to taking it there cause I tried everything else. For everyone that helped comtribute to this thread thank you for your input. It was much appreciated. If anything else comes up I will post it up here.
And welcome to the LS1tech forums. Set yourself up with a basic signature so everybody can see what you have. There's a lot of good info for you and your car here that can save you a lot of heartache, money and from being screwed around by repair shops. As you look to be no stranger to turning a few bolts, there's a few easy ways to improve power and how your car runs.
BTW, nobody reads the newbie threads...
BTW, nobody reads the newbie threads...
Thread Starter
Teching In
Joined: Oct 2010
Posts: 31
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From: Oklahoma City, Oklahoma
I ended up having to put a new pcm in the car from the dealership. That cost me 700 dollars. The circut that sends the signal down the excitor to the alternator had totally arched out and was done for. I then had to go back down and get another alternator cause it still wasnt working. The alternator that I had that tested good 8 times or so had a back plug in on the back, the machines dont test the back plug only to see if it is producing a charge or not.
I ended up having to put a new pcm in the car from the dealership. That cost me 700 dollars. The circut that sends the signal down the excitor to the alternator had totally arched out and was done for. I then had to go back down and get another alternator cause it still wasnt working. The alternator that I had that tested good 8 times or so had a back plug in on the back, the machines dont test the back plug only to see if it is producing a charge or not.
