Alternator help?

**undertakersT/A** · 02-02-2006, 10:19 AM

My son has a 97 Trans am, big cam, msd ignition,2500 stall conv. shift kit, 4.10rear gear 5.7 motor. Recently we changed the alt. to a high output unit. At 2800rpm it will stop charging even if we free rev it 2800 rpm.no charge any ideas. Someone said try the battery. I took the battery from my vette and tried did the samething. Removed the alt and had it tested checked out fine. Anyone have any suggestions or have experienced this problem. 55 degrees and sunnyin cleveland can u believe it for February, and he wants to drive.cant blame him.

Thanks , Undetaker

**gnomee** · 02-02-2006, 02:52 PM

Well I'll state the obvious... Did you get the alt checked out? If so check the cables, maybe they are rattling to much at 2800 plus and loosing connection.

**undertakersT/A** · 02-03-2006, 05:48 AM

gnomee; thanks for responding. I did remove the alt. and have it tested . it checked out ok. cables are tight. I am trying a new battery today. Everyone i talked to that i race with said its the battery. I tried my vette battery but its two years old, so today i will try a brand new optima and see.
Thanks again, Undertaker

**gnomee** · 02-03-2006, 07:18 AM

Let us know if the battery fixes it. It will be a strange one if it does. If the battery in your vette works fine in it then it should work on this. Unless it just has a real real picky voltage reg.

**undertakersT/A** · 02-03-2006, 07:53 AM

hey, the battery did not work. It did however let me go to a higher rpm range about 4000rpms before it started not to charge. I can not figure this out. It has a new dist, msd box and alt. all check out fine. cables are connected tight and clean. any ideas?
Undertaker

**gnomee** · 02-03-2006, 09:24 AM

Well since the voltage regulator is built into the alternator I would just swap the alternator out. I have had the local Autozones test equipment call an alternator and a starter good yet on the car they flake out for one reason or another. The only other thing it could be if the alternator for sure is good even after swapping it out would be some wiring in the charging system shorting out. Have you guys installed a stereo system? Alot of times an amp or a capacitor can cause a big draw and make funky things happen. If it were a wiring issue, most likely it would just not work and deffinetly would not be so consistant as to the rpm. I say you got a bad voltage regulator in your alternator and you should just swap it out. Really the only thing it can be.