ALT quits at 5K?
01-31-2010, 12:09 AM
#1
ALT quits at 5K? so like the title says the alt on my 99 Z28 just stops working at 5K RPMs. Doesnt matter if I go WOT or ease into it, volts drop from 14.3 into the red. All battery wiring,pos and neg, check good. Exciter wire is fairly new and checks good. I just dont know whats happening a ~5K that would cause this. Alt works fine as long as the engine stays under 5K. Willing to entertain any ideas.
01-31-2010, 10:09 AM
#2
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Might want to make sure your power steering pump isn't leaking. I recently replaced mine because it was leaking from the shaft - right above the alternator. Maybe also check your serp belt condition and the tension spring on your idler pulley in case you have belt slippage.
01-31-2010, 11:50 AM
#3
belt is a fairly new gatorback, tensioner is keeping belt tight. PS pump did leak onto the alt a few months ago, but is dry now.
Used a VOM to test the exicter wire from pinout 15(?) to the alt and it tested good. Guess its time to buy an alt and see what that does.
Used a VOM to test the exicter wire from pinout 15(?) to the alt and it tested good. Guess its time to buy an alt and see what that does.
01-31-2010, 01:44 PM
#4
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obd2 vehicle turns the alternator and a/c off at upper RPM's to increase power output. Now on my car the gauge does not go into the red but i can tell by my handheld that the alt will quit charging at that RPM's.
01-31-2010, 04:02 PM
#5
After checking all that crap looks the the alt was no good, of all the fookin things it could be. Voltage stays steady from 5k all the way to 7k, nice difference in power as well. Thanks for the help.
01-31-2010, 06:44 PM
#6
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never heard of it shutting the alt off, kinda needs the voltage for the injectors. Anyways...
After checking all that crap looks the the alt was no good, of all the fookin things it could be. Voltage stays steady from 5k all the way to 7k, nice difference in power as well. Thanks for the help.
After checking all that crap looks the the alt was no good, of all the fookin things it could be. Voltage stays steady from 5k all the way to 7k, nice difference in power as well. Thanks for the help.
I understand your thinking, but how often and how long do you keep the car over 5k. Probably not that long. BMW (I am a BMW tech) has been doing this since 96ish and they have better ignition/fuel system that these GM products. The newer cars have direct injection which pulls more current to fire them and they still cut the alt off.
but glad you found your problem. The regulator must have been bad.
02-02-2010, 10:36 AM
#7
Mine did the same thing, except the voltage at which it cut out got lower and lower until it wouldn't charge must past Idle. Broken wire in the field. It was a reman that I had for about 3 months and already had all rectifier and regulator replaced with OEM parts because it died after 1 month.
