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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Thu Oct 18, 2018 9:26 am Post subject: Electrical Oddity In Tucson AZ |
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This car has been so reliable for so long, but here we are with an oddity that I'd like to address before taking off across Texas today.
1977 factory alternator and regulator and two year-old battery
a) ignition on/engine off - headlamps show normal battery-driven brightness
b) engine running - headlamps brighten to normal running intensity
c) engine slowed down with clutch against ebrake- headlamps dim to nothing
d) last night, I stalled engine to see if voltage regulator would decouple alternator from battery and give me headlamps back to (a) above, and everything went dark dead gone.
e) this morning, car started normally.
Question, can voltage regulator keep the battery from the electrical system?
Colin
_________________ www.itinerant-air-cooled.com |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Thu Oct 18, 2018 9:37 am Post subject: Re: Electrical Oddity In Tucson AZ |
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Telford is on it _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
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Boeing 727,737-200-300-400,757,767
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DC9/MD80
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3547 Location: San Diego (Encinitas)
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Posted: Thu Oct 18, 2018 9:44 am Post subject: Re: Electrical Oddity In Tucson AZ |
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Amskeptic wrote: |
This car has been so reliable for so long, but here we are with an oddity that I'd like to address before taking off across Texas today.
1977 factory alternator and regulator and two year-old battery
a) ignition on/engine off - headlamps show normal battery-driven brightness
b) engine running - headlamps brighten to normal running intensity
c) engine slowed down with clutch against ebrake- headlamps dim to nothing
d) last night, I stalled engine to see if voltage regulator would decouple alternator from battery and give me headlamps back to (a) above, and everything went dark dead gone.
e) this morning, car started normally.
Question, can voltage regulator keep the battery from the electrical system?
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In a word, no. Voltage regulators only modulate the rotor current to keep the alternator output voltage constant. Sounds like a connection issue in the main feed wire from the starter to the fuse block, a battery terminal problem, battery wire connection to starter and body ground, the battery itself, or a fuse block problem. (I'm skipping the trannie ground strap, as that affects mainly engine operations.)
"C", above, may be the key: it implies that the battery/related wiring is going intermittently open circuit, and the bus is running strictly off the alternator. When it drops out at low engine speed, the electricity goes away.
The trick is to catch it in failure mode, then probe with a test light and see where the power stops on its way to the front of the bus. _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)
Last edited by telford dorr on Thu Oct 18, 2018 10:02 am; edited 4 times in total |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Thu Oct 18, 2018 9:56 am Post subject: Re: Electrical Oddity In Tucson AZ |
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There, now I've done my good deed for the day _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Thu Oct 18, 2018 10:48 am Post subject: Re: Electrical Oddity In Tucson AZ |
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telford dorr wrote: |
"C" implies that the battery/related wiring is going intermittently open circuit, and the bus is running strictly off the alternator. When it drops out at low engine speed, the electricity goes away.
The trick is to catch it in failure mode, then probe with a test light and see where the power stops on its way to the front of the bus. |
I will be investigating further today. I do not experience anything intermittent with this suite of symptoms.
a) I know there is a cut-in in the regulator (thus, it is a cut-out too).
b) I do not understand how the alternator is allowed to run the electrical system at what appears to be 2 or 3 volts with a fully charged battery just waiting to supply the 12 volts it definitely has. If it were a cable issue, I would think that starter draw would test that. Starter operates fine. Red/white main supply wire to fuse box buss is snug and very clean at both ends.
c) I have seen voltage regulator contacts go from one pole to another as engine starts (thanks YouTube!) . . . what if the contact stays stuck "on"?
ColinInTucson _________________ www.itinerant-air-cooled.com |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Thu Oct 18, 2018 10:49 am Post subject: Re: Electrical Oddity In Tucson AZ |
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Colin in Tucson - We are headed to Los Angeles this weekend but will be back Sunday. You are welcome here if you decide to limp along. Pensacola is going to be a mess because of Michael's damage one hour east of there. My brother lived in Pensacola then Panama City Beach many years, and my late parents were in Fort Walton Beach for 35 years. Your failure mirrors the battery failure in the 2006 Acura RL about 5 years ago. One minute it was running, I stopped with the AC running on high on a 110F day, the voltage flared, and 10 seconds later the engine died and everything went dark. A test of the battery the week before said it was very strong but I was having some issues with lights flaring etc. occasionally.
for others who might read this is in the future here are possible places that failure might occur IMHO. (not in any specific order)
Intermittent ground strap
Intermittent power cable from battery (could be rotted internally)
Intermittent connection at the power plug near base of late column
Ignition switch going bad
Failing battery where either + or - side has a failed battery post internally
Loss of 12V+ at the fuse panel
The key is that the dash went dark. Combined with headlight flaring this implies that the 12V+ voltage or grounds are in an unstable state. When the RPM falls low enough the ECU FI system falls out and then the alternator drops out completely. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Thu Oct 18, 2018 11:33 am Post subject: Re: Electrical Oddity In Tucson AZ |
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I sent you a PM, but here is the public musing:
I, too, had visions of some horrific current draw, but nothing of the sort happened.
Ignition switch is fine. Components upstream of the ignition switch such as parking lights died too!
What does that cut-in contact in the regulator do?
1) It keeps the alternator out of the electrical system if it is not charging, yes? (cut-out)
2) It adds the alternator into the electrical system if it is charging, yes? (cut-in)
So what would happen if the contact keeps the alternator cut-in below threshold (2)? Does it give the whole electrical system to the alternator and tell the battery to stay out? That doesn't even make sense. I have the alternator B+ terminal right against the battery cable end at the starter solenoid.
Do you have any notions that some damn main alternator diode is committing a path to ground only when regulator is allowing alternator into the circuit?
Colin ?? _________________ www.itinerant-air-cooled.com |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Thu Oct 18, 2018 11:43 am Post subject: Re: Electrical Oddity In Tucson AZ |
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replied to PM
Generators try to run as a motor when the engine is stopped. The cut out prevents this. Alternators do not have this property.
Likely to be battery internally or one of the power cables from it e.g., ground strap or 12V + power cable.
If there is a second battery it could be the battery switching unit too. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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telford dorr Samba Member
Joined: March 11, 2009 Posts: 3547 Location: San Diego (Encinitas)
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Posted: Thu Oct 18, 2018 12:46 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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Amskeptic wrote: |
What does that cut-in contact in the regulator do?
1) It keeps the alternator out of the electrical system if it is not charging, yes? (cut-out)
2) It adds the alternator into the electrical system if it is charging, yes? (cut-in) |
No, the diodes inside the alternator do that. Only a generator regulator needs a disconnect relay (which, by the way, can be replaced with a diode...)
The alternator regulator should have only one relay which modulates the alternator rotor current. If yours has two, then something is wrong. Are you sure someone, sometime, didn't install a generator regulator?
Generic alternator wiring:
Here's a '73-'74 schematic highlighting the alternator circuit (basically the same in all late bays):
Note that (1) there is no regulator between the alternator and the battery, (2) the starter terminal is the mecca point for the battery, the alternator, and the rest of the bus, and (3) either the battery or the alternator or both can power the bus. Therefore, if the bus goes dark, then neither battery power or alternator power is getting to the front of the bus. The loss of alternator can be explained by the RPM being too low. That leaves the battery as at least part of the problem - it's power is not getting through.
What is your voltmeter telling you?
[The fact that the bus starts is just an annoyance created by the bus just to tick you off. Even though it's illogical, in this case don't be distracted by it. ] _________________ '71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Thu Oct 18, 2018 1:33 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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Seems to me if all else fails go get yourself a spare battery _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
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78BusGA Samba Member
Joined: February 01, 2017 Posts: 315 Location: Buford, Georgia
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white74westy Samba Member
Joined: May 02, 2011 Posts: 777
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Posted: Thu Oct 18, 2018 3:38 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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Dead cell? |
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Amskeptic Samba Member
Joined: October 18, 2002 Posts: 8568 Location: All Across The Country
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Posted: Thu Oct 18, 2018 6:52 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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Though I will never understand how the starter was able to turn so merrily, with such verve, I do believe the problem has been solved.
Removed entire positive battery cable and the sheath over the cable for a very close inspection, all is factory fresh. Reinstalled it through all factory grommets and harness protectors. Removed alternator B+ wire and performed a similar close inspection, it is fine.
Unbraided the factory cable after removing it from an aftermarket terminal:
Straightened and raked each strand with a razor blade, then re-braided:
Reinstalled cable to aftermarket terminal and stuck on a little heatshrink tubing where the insulation was stripped back too far (some time back in the eartly 1990's):
Car is fine now, and thank you to all who chimed in.
Colin
(p.s. while rummaging for my asiab3 Commemorative New Battery Box Drain Valve, I found my spare regulator (way too late which I am happy about, no hopeful useless parts installation). But the new drain valve kept falling through the replacement battery box drain hole because it is bigger than the oem drain holes. A shifter bushing for a 1993 BMW 5 Series was the perfect hole reducer drain valve support)
_________________ www.itinerant-air-cooled.com |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50255
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Posted: Thu Oct 18, 2018 8:13 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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I strongly recommend using the replacement cable ends for temporary EMERGENCY use only. They are notorious for being installed and then ignored until they have caused problems and often lead to expensive and unnecessary repairs being done. I can buy a battery cable a size or two larger than stock from my local Napa and have them cut it to the length I want and crimp on the end that I desire for very little moola . |
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wcfvw69 Samba Purist
Joined: June 10, 2004 Posts: 13382 Location: Arizona
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Posted: Thu Oct 18, 2018 8:31 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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Wildthings wrote: |
I strongly recommend using the replacement cable ends for temporary EMERGENCY use only. They are notorious for being installed and then ignored until they have caused problems and often lead to expensive and unnecessary repairs being done. I can buy a battery cable a size or two larger than stock from my local Napa and have them cut it to the length I want and crimp on the end that I desire for very little moola . |
X2
I hate those connectors. They cause more issues than anything.
http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=211971228A
I had an intermittent start issue on my bus, mainly when the engine was at temperature and the starter was heat soaked. It had cheap, crappy battery cables on it w/those lousy connectors. I replaced both the ground and positive cables with these from WW. Problem gone. I was amazed with how much faster the starter spun after installing the new battery cables. _________________ Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50255
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Posted: Thu Oct 18, 2018 8:43 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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wcfvw69 wrote: |
Wildthings wrote: |
I strongly recommend using the replacement cable ends for temporary EMERGENCY use only. They are notorious for being installed and then ignored until they have caused problems and often lead to expensive and unnecessary repairs being done. I can buy a battery cable a size or two larger than stock from my local Napa and have them cut it to the length I want and crimp on the end that I desire for very little moola . |
X2
I hate those connectors. They cause more issues than anything.
http://www.wolfsburgwest.com/cart/DetailsList.cfm?ID=211971228A
I had an intermittent start issue on my bus, mainly when the engine was at temperature and the starter was heat soaked. It had cheap, crappy battery cables on it w/those lousy connectors. I replaced both the ground and positive cables with these from WW. Problem gone. I was amazed with how much faster the starter spun after installing the new battery cables. |
Better connections and larger cables equate to more voltage at the starter, which in turn equates to a faster cranking speed and less current draw, which in turn equates to easier starting and longer starter, battery, and alternator life. Hard to find a down side to spending some funds here. |
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aeromech Samba Member
Joined: January 24, 2006 Posts: 16922 Location: San Diego, California
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Posted: Thu Oct 18, 2018 9:19 pm Post subject: Re: Electrical Oddity In Tucson AZ |
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So Colin, if you ever make it to my house in San Diego, we’ll use my bulk welding cable and hydraulic swagger for a couple custom cables. They won’t be stock, just better. _________________ Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
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thewalrus Big Jack
Joined: March 27, 2006 Posts: 3014 Location: Belchertown, MA
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Posted: Fri Oct 19, 2018 4:12 am Post subject: Re: Electrical Oddity In Tucson AZ |
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SGKent wrote: |
for others who might read this is in the future here are possible places that failure might occur IMHO. (not in any specific order)
Intermittent ground strap
Intermittent power cable from battery (could be rotted internally)
Intermittent connection at the power plug near base of late column
Ignition switch going bad
Failing battery where either + or - side has a failed battery post internally
Loss of 12V+ at the fuse panel |
I've been having an issue where my headlights flare/brighten up for a few seconds randomly and then go back to normal. I'll check these spots out. Thanks! _________________ '73 Transporter 1.7L Dual Carb
notchboy wrote: |
You ran over some #Vanlife'ers hopes and dreams? |
60vwnewengland wrote: |
Looking forward to next weekend, weed, krunk juice, hookers, blow, hanging with bums, philly, ...the awards! |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Fri Oct 19, 2018 5:16 am Post subject: Re: Electrical Oddity In Tucson AZ |
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Quote: |
flare/brighten up for a few seconds randomly and then go back to normal. |
probably different cause. That sounds like your VR. You'll need a VOM to watch the voltage when it does it. Also - if you have an older points style VR you can clean the points a little very carefully not to bend them and see if that helps. They may be sticking together. _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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thewalrus Big Jack
Joined: March 27, 2006 Posts: 3014 Location: Belchertown, MA
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Posted: Fri Oct 19, 2018 5:17 am Post subject: Re: Electrical Oddity In Tucson AZ |
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It always happens when I'm driving and the headlights are on so checking the voltage would be tricky _________________ '73 Transporter 1.7L Dual Carb
notchboy wrote: |
You ran over some #Vanlife'ers hopes and dreams? |
60vwnewengland wrote: |
Looking forward to next weekend, weed, krunk juice, hookers, blow, hanging with bums, philly, ...the awards! |
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