Generating problems

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  #1  
Old 03-27-06, 05:26 PM
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Exclamation Generating problems

I am a newbee to this thread and board. I am truly perplexed by my old Dodge pickup. It is a 1976 D100 with 400 cu in engine, auto, PS, PB, etc. It has about 106k miles. Just recently it started to show significant over-voltage indication 16-17+ volts. I immediately suspected and replaced the voltage regulator---NO CHANGE! Now there arn't too many parts to this charging system, so I then replaced the alternator---NO CHANGE! Now, where the heck do I go now? I also tried a new ballast resistor with NO CHANGE! The alternator is good and shows output to specs. (The battery is also new) What am I missing?

bill in las cruces
 
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  #2  
Old 03-27-06, 05:38 PM
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With truck running test voltage at batt. see if it is 13-14 volts, I think your gage in truck is off. (This is just my opinion.) PS sounds like a nice truck.
 
  #3  
Old 03-27-06, 05:50 PM
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For proper voltage regulation you need a good ground with clean connections from the regulator to ground. The regulator will use the ground across an internal resistor for comparison to set the output in a feedback loop. Also get a second opinion from another volt meter. if you only have one; try it on another car that is running. if it is built into the car use a voltmeter across the battery when running you can buy them fairly cheap at radio shack or something. there really isn't much of a difference from the expensive ones to cheap with accuracy.
 
  #4  
Old 03-28-06, 03:10 AM
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generating problems

Thanks guys---I wish it was as simple as a bad voltmeter---checked with several meters and one at the auto parts store----voltage was indeed running high. I will check the ground on the voltage regulator and see if the ground is bad and will advise. Thanks guys (and gals if appropriate)

bill in las cruces
 
  #5  
Old 03-28-06, 02:34 PM
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I know you said new batt. but if not fully charged amp meter to show over charge untill batt. is fully charged. (This is just my opinion.)
 
  #6  
Old 03-28-06, 05:30 PM
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Generating problems

Well, here is an update------cleaning up the ground on the voltage regulator made NO DIFFERENCE! I even put a ground strap on the unit. Kinda hard to figure out----I have a shop manual for the truck, but it is 300 miles from here and it will be a couple of weeks before I can get it.

Also, I am trying to change the valve cover gaskets on the same truck. No problems with the on the right bank, but the left bank cannot be removed fully due to some obstructions---anybody with some experience and some ideas?

Thanks for your collective responses---I really appreciate them.

bill in las cruces
 
  #7  
Old 03-29-06, 02:40 AM
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if its a 2 wire regulator one wire goes to the alternater and if this wire is shorted to ground it would cause it to overcharge as the alternater field will be exited all the time if you unhook the regulator and the 2 smaller alternater wires and check resistance of the wire from alternater to regulator and check to see if there is any resistance to ground which would indicate a short.
with the alternater still unhooked check the other terminal of the voltage regulator for voltage may be key on or battery voltage cant remeber but it should read very close to battery voltage a bad connection, or wire somewhere could cause the voltage to be lower than normal and cause the regulator to overcharge the battery as it uses this voltage to determine when to kick in and out the alternater field.
usually you just remove whatever is in the way to get the valve cover off and change the gasket not much else you can do.
 
  #8  
Old 03-29-06, 03:34 PM
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Smile generating problems --- no more!

Thanks for the information----I found that one of the wires from the voltage regulator to the generator was intermittently grounding. Haven't found the location specifically---somewhere in the harness, so I will install another wire in its place. Thank you all for you assistance and stirring up my brain cells---

bill in las cruces
 
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