I'll start at the top but spare you all the picky details. I went to leave the gas station the other day and the car would barely crank over for some reason. A guy came along with a jump pack and we were able to get it jump started. On the way home I see the voltage drops down to 11.5 at idle, but does increase with engine RPM. I brought the battery to O'Reillys and they said it tested fine. I then brought the whole car there and they hooked up their analyzer to it which says the voltage regulator is bad. The plug on the regulator is in the attached photo. I notice that the red wire is much fatter than the other three. I figure either a previous owner or one of the shops that have done work for me in the past have put a fatter wire there for a good reason. Also the plastic housing is half melted around the fat red wire. It was suggested to me that this could be from a bad ground. I have a new pigtail on order with the connector and my goal is to try to keep that fat wire. There is also a capacitor looking thing attached to a single terminal on the side of the regulator. My understanding is it's purpose is to absorb electrical noise from the plug wires to prevent interference with the radio, is that correct or am I totally wrong? Where is it normally mounted? My regulator is screwed to the firewall and the capacitor thing was just loose between the regulator and firewall. As I look at the replacement regulator the back of it looks different from my old one. I'm concerned that where it was isn't the right place for it and that the case of it would ground out against one of the terminals.
I think that fat wire is stock. The internally regulated alternators are so vastly superior in every way. I would convert over. It's pretty easy.
TTNC, If you want to keep it original .... I have made in U.S.A. ++ DELCO ++ Voltage Regulators, I have the plug that has the four connectors on the top of the voltage regulator and the radio condenser, all separately... Get what you want.... Always best to simply call me --- Craig --- 516 - 485 - 1935... New York...
"There is also a capacitor looking thing attached to a single terminal on the side of the regulator. My understanding is it's purpose is to absorb electrical noise from the plug wires to prevent interference with the radio, is that correct or am I totally wrong?" Yes, that is for radio interference. It is usually connected to one of the screws holding the regulator to the firewall. The case needs to be grounded is all.
http://www.buickperformanceclub.com/alternat.htm I have a 12SI 94 Amp alternator on my car. Never below 14 volts.
I think there's supposed to be an R or P shaped bracket around it with a hole for a ground screw. I don't have it.
I put in a new voltage regulator and pigtail harness while retaining the fat red wire. Not fun but I got it done. Didn't fix the issue. This conversion to an internally regulated alternator may be in the works soon, we'll see what happens after I pull the alternator and get it tested.
After trying two or three ‘new’ regulators with poor results, I bought the $23 chinesium electronic one. It solved the problem, I switched cases and called it done. Worth trying... Patrick
You may have lost magnetism to the alternator. You’ll all have to jump I Think field terminal to bat for a could second to remagnitize alternator. The process is in the service manual.
yup, did that on 2 different cars and 4-5 of USA made regulators and then gave up, bought the cheap electronic one problem solved too !
Looking at the picture , there appears to be a lot of corrosion on the metal terminals. That creates a high amp draw resulting in excessive heat , which would explain the melted area of the connector. Loren
Don't pull the alt yet: There is a real easy test but you have to be very careful... Disconnect the small plug at the back of the alternator. This is the plug to the brush assembly. Find the "F" or field terminal on the alternator. Put your test leads from your voltmeter on the battery to measure the battery voltage. You should read about 12v. Leave them connected. Connect another lead from the positive side of the battery. Use another test lead if you have one. You can use any wire, but you need a small pin connector at the end for the next step. (Keep the free end from touching anything) Start the car. Touch the free end of the test lead connected to the plus side of the battery to the F terminal on the alternator. This will apply a full 12 v to the field coil. On the voltmeter, you should see the voltage on the battery immediately start going up as the alternator starts to charge the battery. This is the careful part as it it not easy to do, especially if you have AC.... As soon as you see the voltage going up, remove the lead from the F terminal. You can do it again to verify, but don't keep the lead on too long as the voltage will keep going up. Try not to touch anything else. This will tell you if the alternator is working. Also, with the engine off, you can touch the same test lead to the R terminal on the plug to the regulator and hear the ignition coil in the regulator click. This will tell you if that's working. Don't try this if the regulator is solid state.... Reconnect the plug to the alternator and you are done. '
If you do the conversion.. This is how I did my bypass for alternator with internal regulator. I reinstall the original cover to hide the wires. Looks factory, charges, and warning light works.
For you guys that are sold on the Chineseum $ 23 solid state voltage regulators, I have the U.S.A. made versions of them -- in the DELCO imitation boxes (if they were in business now, they would have licensing issues!!!) For --- $ 12.00 --- (bought in 1984 !!) Yours, Craig...
The upgrade to a higher amp alternator is sounding like a good idea, especially since the car now has a FiTech setup with a computer and electric fuel pump to keep powered. Where do you have the two pin connector clocked at when viewing from the rear? Did you have to reclock it? What vehicle did it come from? Why do you have the white and red terminals (2 and 3) connected together? From Larrys link above, how to change from an external to an internally regulated alternator, red and white are not connected: Also not sure why it's telling to you tape off the red in step 3. I found this diagram which I think is showing the intended result of the above: We'll see how this goes. I started to pull the alternator yesterday but due to the 90° heat and screwing around with it for three days in a row I gave up. When putting it back together I actually noticed one of the spade terminals in the alternator for the two pin connector was very loose so I smell a replacement alternator in this cars near future. I'm actually bringing the car to a radiator shop today because for some reason the radiator is intermittently weeping coolant from underneath the cap, and it did that for two different caps so they're going to look at the neck on the radiator. They volunteered to look at the charging issue also.
I hate buying Chinesium parts but the electronic one I got off of Amazon solved my issues. It charges well and seems to work as intended. If it fails, I'm going to an internally regulated alternator.
Ide have to go back and look at the schmetic. I think jumping the 2 operate the charging warning light. Cant remember but it works. I have seen jumper wires used in the plug to basically do what I've done. I've just hidden them. There's a couple of ways you can do the bypass and it will charge. Larrys post is one. I did not want to cut my regulator plug off a new harness. Also wanted the warning light to work