Speedy J

Ok well I thought the problem was fixed but it seems to have returned.

About a month ago (after I jumpstarted my 93 vette when I left the interior lights on overnight) my voltage gauge started spiking up to 17. The dash lights would flicker as well as the battery and check gauges lights when this happened. So I disconnected the battery and removed the alternator. I took it into an alternator shop where they told me the alternator and the voltage regulator was fine. I had them replace the regulator anyway since it was fairly cheap and thought it couldn’t hurt. I put the alternator back in and went for a test drive and it spiked up to 17.5 on me once and then it never did it again until a few days ago. We were on our way back from a road trip when it started spiking again up to 17 and then back down. It did this for about 5 miles or so and then just quit. Then on my way to work last night it started doing it again only this time a lot more frequently. I noticed that when it spikes my headlights get super bright and my radio sounds like all the speakers cut out except one as well as the check gauges and battery lights come on for the few seconds it spikes. I also noticed the service engine soon comes on as well but only when it spikes up to 17.7 Then it all drops back 13 or 14volts and everything goes back to normal until it spikes again.
So since I checked the alternator and changed the voltage regulator could it be the battery? Also when I disconnected the battery to remove the alternator could that have temporarily fixed the problem from the computer resetting itself when I re-connected the battery? Any advice on this would be greatly appreciated before i go . Thanks and KEEP THE WAVE GOING

pcolt94

The first thing I would tell you to do is the check the actual voltage with a DVM to verify the problem. Just to make sure you are getting a true indication of the read out on your spedo. But since you indicate all electrical items show signs of over voltage, I’m going to say you probably really do have the problem. I’m going to assume the re-build shop actually changed the regulator.

In that case you probably have a defective battery. I have seen this problem where the battery load characteristics are changing drastically causing the alternator not to be able to control the output voltage properly.

I would not run the car any more in its current situation and get that battery out of there ASAP. You can do damage to all the sensitive devices like the 3 computers plus more. Any battery with a couple years on it can cause this problem. Not real common but can be real serious. Besides having a new battery is best anyway.

rick lambert

have the battery tested, maybe a shorted plate (cell).

jfb

The voltage regulator cannot instantly drop the voltage if the load is suddenly removed and you may have a battery that has an intermittent inter cell connector, or you may have an intermittent battery cable connection. The response time of the alternator however is quick enough that you should only see bright headlights for well under a second. I am still suspicious of the alternator, new regulator aside. Testing in a shop doesn't prove it is defective. I vote for a totally different alternator.

Speedy J

Thanks for your help. Since a new battery is cheaper than a new alternator I'll try that first and see if it works. Besides I'm not sure how old it is anyway since the month is marked off of the battery but not the year. If that dont work then I'll try a new alternator and if that dont work ........well lets just hope it dont go that far.

Thanks again

bigbearwi

What would be a good voltage, after having a dead battery on my 92 it was running at 14.9 or 15.2

Speedy J

I had the battery tested and it checked out fine. Could it still be the prob even though it checked out? I did see when i got it out it was marked Jan of 2006.