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bignic
Samba Member
Joined: May 15, 2010
Posts: 37
Location: Ontario
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 Posted: Mon May 30, 2016 12:25 pm Post subject: Electrical Gremlins - 74 Bug |
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Trying to troubleshoot ignition problems with new coil/wires/distributor and I recently seem to notice that my Voltage indicator is quite often pinned above 16+Volts - not always, but often. Wondering why that is - is the alternator charging causing this? How much does a stock/stock replacement alternator change the voltage at the battery terminals when it is engaged and running at idle? If the alternator is NOT engaged, then am I correct to assume that my voltage reading should be just above 12V?
Also the blinker signals are clicking doubletime so I assume one of them is out but after repeated inspections, I can find no bulbs out anywhere, with the possible exception that my passenger headlamp appears to be about half as dim as the other.
Are these issues related? If so, by what manner of voodoo should I start to diagnose? Could I have a wiring short? Could I have bad fuse/fuses?
Theoretically, could a coil / ballast resistor problem show up like this - in the rest of the car's electrical system?
I've wired my own gauges and they all appear to work fine but perhaps I've done something newb with how I wired the voltage gauge? Still doesn't explain the head lamp / indicator problem though..
Perhaps my bulb is just half burnt out - does anyone know a nominal resistance for these bulbs? ie, if I'm over/under xOhms, the bulb is malfunctioning?
For now, I'll get a multimeter and see if it confirms that there actually IS greater than 16V at the terminals...
Its original wiring and more than one owner so I'm guessing my best bet, unfortunately, is to start considering a new wiring harness but for obvious reasons, I'm not keen on that idea. So I want to try to isolate these problems and solve them first. ... Leave a complete replacement for last resort.
Best case scenario, I learn something and solve the problems. Worse case scenario, I do a full wiring harness replacement and solve the problems. |
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Dale M.
Samba Member
Joined: April 12, 2006
Posts: 20379
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Mon May 30, 2016 2:15 pm Post subject: Re: Electrical Gremlins - 74 Bug |
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Alernator should have output from 13.8 volts (minimum) to about 14.2 votes (maxlmum) anything other indicates bad regulator.... Use good digital meter to measure...Dash meters are notoriously in accurate.... If Bosch alternator, you can get replacement internal regulator...
Dim head lights can be poor grounding , clean and reconnect grounds....
Many problems can be attribuited to dirty and corroded connections, cleaning and application of dielectric grease (anti corrosion grease) can help alot to kill gremlins...
Dale
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bignic
Samba Member
Joined: May 15, 2010
Posts: 37
Location: Ontario
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| Posted: Mon May 30, 2016 4:45 pm Post subject: Re: Electrical Gremlins - 74 Bug |
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How can you tell if the alternator has an internal regulator?
Since in this case, its likely malfunctioning even if it is there - should the alternator have it stamped or something... a sticker even?? |
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mcmscott
Samba Member
Joined: March 12, 2010
Posts: 4856
Location: sanger ca
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| Posted: Mon May 30, 2016 6:17 pm Post subject: Re: Electrical Gremlins - 74 Bug |
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| Dale M. wrote: |
Alernator should have output from 13.8 volts (minimum) to about 14.2 votes (maxlmum) anything other indicates bad regulator.... Use good digital meter to measure...Dash meters are notoriously in accurate.... If Bosch alternator, you can get replacement internal regulator...
Dim head lights can be poor grounding , clean and reconnect grounds....
Many problems can be attribuited to dirty and corroded connections, cleaning and application of dielectric grease (anti corrosion grease) can help alot to kill gremlins...
Dale |
There is a thing called " voltage drop" where your alternator sees, say, 10 volts on the exiter wire(field wire) there fore its regulator goes open and charges like mad, even tho battery voltage is damn near 15 volts. You have a voltage drop problem from the rear of the car back to the front,,,IE bad connection some where.
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bignic
Samba Member
Joined: May 15, 2010
Posts: 37
Location: Ontario
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| Posted: Thu Jun 02, 2016 4:05 pm Post subject: Re: Electrical Gremlins - 74 Bug |
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I'm going to replace the voltage regulator if not the entire unit but I'm curious if a regulator starts to go bad (assuming the battery is good and one could drive on it for a while)
In an emergency, would it damage anything to just disconnect the charging signal (thus turning the alternator off)? |
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