Will a high voltage condition cause any real problems?
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Will a high voltage condition cause any real problems?
I replaced the alternator last week, and the new one just took a crap... SES... Check gauges... the volts were pegged - 17.7!!!!
Will this cause any other real problems? It did it like a block from my house, so I buzzed STRAIGHT home and parked it... turned everything off (ac/stereo/lights) so as to not anger it more as I drove home.
Thanks!!!
Will this cause any other real problems? It did it like a block from my house, so I buzzed STRAIGHT home and parked it... turned everything off (ac/stereo/lights) so as to not anger it more as I drove home.
Thanks!!!
Large Impressive Member
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
No further than you drove it that way, if everything's still working, it'll probably be fine.
Le Mans Master
Joined: May 2004
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From: Hellinois
Finalist 2020 C4 of the Year - Modified
That sounds like your regulator may be somehow grounded or is not working properly. One way to test an alternator for charging is to put a small screwdriver in a hole on the backside of the alt. The Haynes manual shows it. This will cause your alt to go to 17+ volts. again this is a test to see if alt is charging but since yours is charging 17.7 by itself then it has to be defective or grounded somehow.
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Agent - that's what I was thinking... but... CKNC confirmed that since everything is working, I am ok!
And since it's a new remaned POS, I will get another remaned POS!!!
Thanks!
And since it's a new remaned POS, I will get another remaned POS!!!
Thanks!
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
17.7 volts for the several blocks you drove won't hurt your battery. But if smoke comes out of the dash, the MOV (metal oxide varistor) that is on the power supply board in your cluster could overheat and burn up.
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
thanks, guys!
I just got back from the Kragen... the alt passed their tests, but, it is also a cold alt... so heat could change everything.
I am going to check all connections in the AM and make sure the harness to the alt is ok, then reinstall and drive. If it goes nuts, I will limp over to the parts shop. It's no more than 3 miles to there from my house, so it won't be a real issue... I will be nearby anyway.
I just got back from the Kragen... the alt passed their tests, but, it is also a cold alt... so heat could change everything.
I am going to check all connections in the AM and make sure the harness to the alt is ok, then reinstall and drive. If it goes nuts, I will limp over to the parts shop. It's no more than 3 miles to there from my house, so it won't be a real issue... I will be nearby anyway.
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Team Owner
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From: Cincinnati, Oh USA
It isn't the battery!!!!! The voltage regulator in the alternator maintains 14.7 volts output even with the battery disconnected !!!!!
You have an alternator problem if its output voltage is 17+ volts.
You have an alternator problem if its output voltage is 17+ volts.
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Originally Posted by jfb
It isn't the battery!!!!! The voltage regulator in the alternator maintains 14.7 volts output even with the battery disconnected !!!!!
You have an alternator problem if its output voltage is 17+ volts.
You have an alternator problem if its output voltage is 17+ volts.
my guess? the voltage regulator is bad, but its failure rate increases in relationship to tempature.
Advanced
Joined: Feb 2004
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From: Mission Viejo CA
Now that you've got the car home, time to do the following...
Disconnect the belt that turns the alternator and other accessories. Using an accurate DMM, check the voltage at the battery AFTER you've started the car. (It won't hurt to run the car for a minute or so without the belt) What is your voltage? Should be 10 - 11 volts; remember you're using battery power. Next, re-install the belt. Check the voltage again. If you're over 14.5 Vdc, you've got a regulator problem. The electrical components, computers and the like, aren't designed to withstand voltages of above 15 Vdc for extended periods of time. Internal damage may occur causing weird electrical problems in the future. You did mention that you purchased the alternator from Kragen. I've heard this type of story way too frequently about their parts. I would recommend using one of the AC Delco reman's. from one of the online vendors. I purchased one from GMPartsDirect for my '96. You've heard the old adage: "you get what you pay for".
Disconnect the belt that turns the alternator and other accessories. Using an accurate DMM, check the voltage at the battery AFTER you've started the car. (It won't hurt to run the car for a minute or so without the belt) What is your voltage? Should be 10 - 11 volts; remember you're using battery power. Next, re-install the belt. Check the voltage again. If you're over 14.5 Vdc, you've got a regulator problem. The electrical components, computers and the like, aren't designed to withstand voltages of above 15 Vdc for extended periods of time. Internal damage may occur causing weird electrical problems in the future. You did mention that you purchased the alternator from Kragen. I've heard this type of story way too frequently about their parts. I would recommend using one of the AC Delco reman's. from one of the online vendors. I purchased one from GMPartsDirect for my '96. You've heard the old adage: "you get what you pay for".
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Originally Posted by mvmechanic
Now that you've got the car home, time to do the following...
Disconnect the belt that turns the alternator and other accessories. Using an accurate DMM, check the voltage at the battery AFTER you've started the car. (It won't hurt to run the car for a minute or so without the belt) What is your voltage? Should be 10 - 11 volts; remember you're using battery power. Next, re-install the belt. Check the voltage again. If you're over 14.5 Vdc, you've got a regulator problem. The electrical components, computers and the like, aren't designed to withstand voltages of above 15 Vdc for extended periods of time. Internal damage may occur causing weird electrical problems in the future. You did mention that you purchased the alternator from Kragen. I've heard this type of story way too frequently about their parts. I would recommend using one of the AC Delco reman's. from one of the online vendors. I purchased one from GMPartsDirect for my '96. You've heard the old adage: "you get what you pay for".
Disconnect the belt that turns the alternator and other accessories. Using an accurate DMM, check the voltage at the battery AFTER you've started the car. (It won't hurt to run the car for a minute or so without the belt) What is your voltage? Should be 10 - 11 volts; remember you're using battery power. Next, re-install the belt. Check the voltage again. If you're over 14.5 Vdc, you've got a regulator problem. The electrical components, computers and the like, aren't designed to withstand voltages of above 15 Vdc for extended periods of time. Internal damage may occur causing weird electrical problems in the future. You did mention that you purchased the alternator from Kragen. I've heard this type of story way too frequently about their parts. I would recommend using one of the AC Delco reman's. from one of the online vendors. I purchased one from GMPartsDirect for my '96. You've heard the old adage: "you get what you pay for".
However, getting what I pay for, and what I can afford right now, are diametrically opposed! This alt is a stop gap until I can afford to get a new or remanned GM unit.
Thanks for the tips!!!
Interestingly enough, I got the same brand (OEM) from Advance Auto about 3 years ago to replace my starter, and it's going a-ok!
Off to troubleshoot!
Thread Starter
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Just got back in. The alt is toast.
I went through the testing process that mvmechanic so kindly wrote down. The battery seems ok. It was hitting 11.7vdc on my Fluke.
So... I reconnect everything... start it up. First, the alt is slow to generate power at low RPM. So, I gas it a bit. What happens next is most exciting.
As the revs climb, so does the voltage... at a constant 1500rpm, all it took was about 15 seconds and I was back to 17.7vdc and a high voltage warning. Neato, eh?
I then shut everything down, waited a moment then refired the car. This time, the voltage is stuck at 12.2vdc and dropping! I shut it off at 11.9vdc.
Up. DOA voltage regulator.
Last night, when the dude at Kragen was testing it, I asked at what RPM was this tested at, and he didn't know. My guess? no more than 600rpm. And it's fixed.
Off I go to Kragen again. My neighbour across the street is going to run me up there!
Thanks for all the help! I will keep you all posted!!
I went through the testing process that mvmechanic so kindly wrote down. The battery seems ok. It was hitting 11.7vdc on my Fluke.
So... I reconnect everything... start it up. First, the alt is slow to generate power at low RPM. So, I gas it a bit. What happens next is most exciting.
As the revs climb, so does the voltage... at a constant 1500rpm, all it took was about 15 seconds and I was back to 17.7vdc and a high voltage warning. Neato, eh?
I then shut everything down, waited a moment then refired the car. This time, the voltage is stuck at 12.2vdc and dropping! I shut it off at 11.9vdc.
Up. DOA voltage regulator.
Last night, when the dude at Kragen was testing it, I asked at what RPM was this tested at, and he didn't know. My guess? no more than 600rpm. And it's fixed.
Off I go to Kragen again. My neighbour across the street is going to run me up there!
Thanks for all the help! I will keep you all posted!!
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by jfb
It isn't the battery!!!!! The voltage regulator in the alternator maintains 14.7 volts output even with the battery disconnected !!!!!
You have an alternator problem if its output voltage is 17+ volts.
You have an alternator problem if its output voltage is 17+ volts.
Last edited by Corvette Kid; Aug 3, 2004 at 05:00 PM.
Drifting
Joined: Mar 2004
Posts: 1,504
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From: Byron Center MI
Originally Posted by bogus
that's my thinking, however, the dude at the parts shop suggested the connection to the alt might be bad, so, at the very least, I will check that.
my guess? the voltage regulator is bad, but its failure rate increases in relationship to tempature.
my guess? the voltage regulator is bad, but its failure rate increases in relationship to tempature.
Thread Starter
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
I took the old alt back to Kragen, tested, it was dead this time... replaced, new one in.
I am getting good at this... I swear... 15 minutes each way. I wonder what this bills?
I am getting good at this... I swear... 15 minutes each way. I wonder what this bills?
