Wandering Voltage
Thread Starter
Pro
Joined: Feb 2005
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From: Moore South Carolina
Wandering Voltage
Hi, Everyone - I'm a new Corvete owner - '92, 6-speed, LT1, with wandering voltage for the last 2 days. The car was fine up until that point. I've been reading threads and think my alternator is going (130K on car). It will run in the range of 13.5-14.7 volts for a while ( according to dash) and then drop off to just battery voltage (11.4-12.1) - it seems to drop when I accelerate - and a few minutes later the voltage will come back up to 14.5. I can usually get the voltage to come back up to the 13's/14's by taking my foot off the gas.
Is this how an alternator usually fails? I don't know if it just dies and leaves you on battery power or if it could lose control and show these voltage swings for a while before completely crashing on me.
Is this how an alternator usually fails? I don't know if it just dies and leaves you on battery power or if it could lose control and show these voltage swings for a while before completely crashing on me.
Cruising
Joined: Feb 2005
Posts: 14
Likes: 0
From: Clermont Fl
I think you're right - usually the voltage regular goes out and gives unsteady voltage. If this is so, you should also notice the instrument lcd flicker also. Best bet, buy another alternator.
Picked this up from another thread:
"Sounds like the internal regulator of your alternator. It would probably be cheaper to have your regulator changed than buy a new alternator. I just had my entire alternator rebuilt. The brushes, regulator, etc. were changed and I only paid $45.
Call Jerry at 941-922-2709. Send him your alternator and he'll send you a rebuilt one for a great price. He does great work. turnaround is fast too. He did mine."
Picked this up from another thread:
"Sounds like the internal regulator of your alternator. It would probably be cheaper to have your regulator changed than buy a new alternator. I just had my entire alternator rebuilt. The brushes, regulator, etc. were changed and I only paid $45.
Call Jerry at 941-922-2709. Send him your alternator and he'll send you a rebuilt one for a great price. He does great work. turnaround is fast too. He did mine."
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
It has all the ear marks of a failing regulator, but the description, EXACTLY fits the symptoms of a slipping belt. That is an unusual problem on these cars, but it wouldn't hurt to check it out.
RACE ON!!!
RACE ON!!!
Thread Starter
Pro
Joined: Feb 2005
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From: Moore South Carolina
Thanks, Fish-N-Vettes, CFI-EFI
Thanks, Guys. The LCD is flickering. I should have mentioned that. I thought about the belt slipping earlier - this morning the Voltage DID level out after about 30 minutes on the road after the car heated up as if the belt started spinning properly. I do not hear any squealing or what I would expect a slipping belt to sound like. The belt looks fine - no cracks or visual wear. If felt like it was tensioned ok when I checked it last night. How can I check if it is slipping or not? I haven't really inspected the tensioner yet, either.
Drifting
Joined: Aug 2004
Posts: 1,400
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From: Oceansaide CA
If it keeps fluctuating like that, I'd check my wiring first. Don't trust pepboys/autozone for checking your alt, i've had them be wrong before. But make sure all the wires are on, battery terminals, etc first before you buy anything. Pop the hood and move whataver related wires you can by hand and have someone watch the guage. Turn on all possible electric accessories and try and see if the belt is slipping meybe? I had this happen when it was raining - belt got all went when i went through some mondo puddles, and my voltage dropped until I let the car sit for the night.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Like I said, a slipping belt isn't common with serpentine belts, but your symptoms mimic a slipping belt. The obvious causes would be weak tension or an electrical short somewhere that is overloading the alternator to the point that the belt can't take the load. It's a long shot based on your description of the problem. Then again, maybe the belt isn't slipping.
RACE ON!!!
RACE ON!!!
Thread Starter
Pro
Joined: Feb 2005
Posts: 591
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From: Moore South Carolina
Found the Fluctuating Voltage Problem - Wiring!!
Came home this evening and dug under the hood. The belt is fine. Tensioner is in the middle of the scale. I turned all accessories on and had my wife rev the engine while I monitored with a handheld meter. The belt didn't slip and the voltage was all over the place constantly. I wiggled the battery and alternator wiring, but couldn't tell if there was any response or not since the voltage wouldn't settle down.
I started removing the alternator to take with me to NAPA to avoid a core charge. After removing all bolts, when I raised the alternator up the wiring plug that's connected to the regulator just fell out. At some point a past owner has cracked the plug and broken the insulation on the wiring to the regulator. After taping it up until I can get a replacement at the dealer, the voltage is rock steady between 14.3 and 14.5 volts. Thanks for all your input!!
I started removing the alternator to take with me to NAPA to avoid a core charge. After removing all bolts, when I raised the alternator up the wiring plug that's connected to the regulator just fell out. At some point a past owner has cracked the plug and broken the insulation on the wiring to the regulator. After taping it up until I can get a replacement at the dealer, the voltage is rock steady between 14.3 and 14.5 volts. Thanks for all your input!!
