Voltage regulator stuck open?
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Started the car today for the first time in 4-5 days (we've had terrible freezing weather/ice here in Texas), and the voltage jumped and set the voltage high DTC, then once it warmed up all was well. I can shut the car off and immediately restart and voltage stays constant, no spike at all. If I let it sit a while and start it the voltage will jump again. Not sure if the voltage regulator is "frozen open" because of the temps/ humidity in the air here then it thaws out, or if there may be another problem. Your help is much appreciated.
Last edited by Dcollins3208; Dec 10, 2013 at 10:14 PM.
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
That's actually what I was beginning to think because the car wouldn't start this morning but could be jumped. Battery is on trickle charge as we speak, will update this evening.
Drifting
Joined: Jun 2013
Posts: 1,957
Likes: 342
From: Shell Point (Crawfordville) Florida
You need to get the battery on a regular charger to get it fully charged first. A "trickle" charger is usually meant as something which will maintain a battery' s charge when left standing for prolonged periods, but will not recharge a dead battery as the output is too low.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
The voltage regulator is electronic so it's doubtful it can "freeze open".
The voltage should not charge way high even with a low battery. The regulator should still hold the voltage in the 14V-15V range.
Maybe you could be a little more clear about what you mean by "the voltage jumped". What voltage level? How long?
The voltage should not charge way high even with a low battery. The regulator should still hold the voltage in the 14V-15V range.
Maybe you could be a little more clear about what you mean by "the voltage jumped". What voltage level? How long?
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
The voltage regulator is electronic so it's doubtful it can "freeze open".
The voltage should not charge way high even with a low battery. The regulator should still hold the voltage in the 14V-15V range.
Maybe you could be a little more clear about what you mean by "the voltage jumped". What voltage level? How long?
The voltage should not charge way high even with a low battery. The regulator should still hold the voltage in the 14V-15V range.
Maybe you could be a little more clear about what you mean by "the voltage jumped". What voltage level? How long?
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Heel & Toe
Joined: May 2012
Posts: 23
Likes: 1
From: Scottsdale Arizona
Basically, when an alternator does not see a "load", the voltage will go high. Sometimes really high. You were lucky that it was a loose connection and making intermittent connection else you would have fried the alternator and maybe other electronics. Makes me want to go and check my connections.
Good Luck, Joe
Good Luck, Joe
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
I agree, very glad it didn't fry anything. Headers will be coming off very soon so I can apply locktite to hopefully prevent this from happening again. I had initially written this off thinking it couldn't be the cause because I replaced the starter around 1-2 months ago and had tightened the nuts pretty tight.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Actually there is a voltage sense line that goes from the starter solenoid back to the alternator. That wire is how the regulator reads the B+ voltage on the BATT Output terminal on the back of the alternator. If that SENSE wire is open or has a poor connection, the alternator goes to full output.
Bill
Bill
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Thanks dadaroo. Although I've fixed my "voltage regulator" problem, it appears I now have another problem I need to track down. I will occasionally get a "charging system fault" as well as a p1637 code. I took a quick look and the gray fusible link wire on the stater solenoid appears to be exposed and frayed; hoping this is what's causing the issue. Pulling the headers off this weekend so i can repair it and will also be applying lock-tite to the nuts, threads, etc so they hopefully will not back off anymore.