Over Voltage

Moderators: Sluggo, Amskeptic

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Over Voltage

Post by Amskeptic » Fri Mar 29, 2013 8:13 pm

drober23 wrote:Colin,
I have a Bentley, and have been using it to diagnose the wiring. blue goes to alt light, and brake switch.

I believe it serves the same purpose in these two points, as well as at the oil switch and fresh air fan switch in the engine compartment. It tells whatever it is connected to that the engine is running.

In my case, there was power feeding back into the blue wire from the brake warning switch.

Once I sort that out, I STILL will have to deal with the overcharging problem.
Yer right. That thar wire goes to the brake warning light. It is not a sentry to tell anyone that the engine is running. It just is. Oil switch is a freestanding separate circuit that uses a grounding switch (the "sender" to complete the bulb circuit.
That regulator D+, that sends 12 volts to the alt warning light to shut it off, also gives the heater blower relay coil the voltage it needs to hold the heater blower relay contacts closed. Your heater lever grounds that relay circuit to energize the heater blower motor right off the starter hot terminal.

Experiment. Disconnect #61 blue from the brake warning light. Protect it from shorts. See if that drops your charging voltage.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Sat Mar 30, 2013 10:00 am

Did some more experimenting. After a bit, the alternator stopped charging at all. Here is what I observe now:

Blue wire to Alternator light: Ignition off: 0v
Ignition on: 0v
Engine Running: 2.1v
If I connect it to the socket, it shows 1.6 V when the ignition is on. I suspect this is the voltage running the light. The voltage with the engine running does not change if I connect or disconnect the wire to the socket, but the lamp lights with ignition on, and stays lit when running.

Socket for the Alternator light: Ignition off: 0v
Ignition on: 12v
Running: 12v

I replaced the brake warning light with a spare. The 61 terminal does not show voltage at ignition any more. Connecting the blue wire to it does not change the readings above any more. It is currently disconnected and protected from shorts though.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Over Voltage

Post by Amskeptic » Sat Mar 30, 2013 9:01 pm

drober23 wrote:Did some more experimenting. After a bit, the alternator stopped charging at all.

Blue wire to Alternator light: Ignition off: 0v
Ignition on: 0v
Engine Running: 2.1v

Socket for the Alternator light: Ignition off: 0v
Ignition on: 12v
Running: 12v
Trouble.

In alternator land.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Sun Mar 31, 2013 2:57 pm

That's what I thought. I expected the red highlight on the 2.1v line, not the 0v with ignition on line though. Am I missing something?

Off to Austria for 2 weeks, so there's lots of time to think it through. I'll swap in a spare when I get back. Thanks again for your patient help.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Mon Apr 22, 2013 5:30 pm

Finally getting a chance to tinker on the bus again. I adjusted the valves and changed the oil. Then I pulled the distributor and popped in a spare. I'll get it settled enough to test tomorrow, and report back then.

The harness looked good, no sign of worn anything. I kept it in the engine to test with the spare alternator. I'll take the alternator I pulled and have it bench tested at my FLAPS.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Over Voltage

Post by Amskeptic » Mon Apr 22, 2013 7:55 pm

drober23 wrote:Finally getting a chance to tinker on the bus again. I adjusted the valves and changed the oil. Then I pulled the distributor and popped in a spare. I'll get it settled enough to test tomorrow, and report back then.

The harness looked good, no sign of worn anything. I kept it in the engine to test with the spare alternator. I'll take the alternator I pulled and have it bench tested at my FLAPS.
Make sure they have provision for testing the excitor diodes. Many a false OK out there. They will test regulator too?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
RSorak 71Westy
IAC Addict!
Location: Memphis, TN
Contact:
Status: Offline

Re: Over Voltage

Post by RSorak 71Westy » Mon Apr 22, 2013 8:46 pm

When the FLAPS bench tests it have them test the blue wire terminal like its a 2nd output. It should put out same voltage as main output terminal.
Take care,
Rick
Stock 1600 w/dual Solex 34's and header. mildly ported heads and EMPI elephant's feet. SVDA W/pertronix. 73 Thing has been sold. BTW I am a pro wrench have been fixing cars for living for over 30 yrs.

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Wed Apr 24, 2013 4:54 pm

I did not get the alternator to a FLAPS yet.

I did swap in a spare alternator, and... overvoltage again. I swapped in a total of three voltage regulators (at least one known good last time it ran) with no change in the overvoltage. Alternator light is out with ignition off, goes on when ignition is on but engine not running, and goes out when the engine starts.

Next is to re-inspect the wiring harness. I have a spare of this too. I may test it for continuity and swap it in. Not sure what else could be involved.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Over Voltage

Post by Amskeptic » Thu Apr 25, 2013 7:00 pm

drober23 wrote:I did not get the alternator to a FLAPS yet.

I did swap in a spare alternator, and... overvoltage again. I swapped in a total of three voltage regulators (at least one known good last time it ran) with no change in the overvoltage. Alternator light is out with ignition off, goes on when ignition is on but engine not running, and goes out when the engine starts.

Next is to re-inspect the wiring harness. I have a spare of this too. I may test it for continuity and swap it in. Not sure what else could be involved.
Man, that is CRAZY.

Make sure that the engine/transaxle ground is GOOD!

Make sure both battery cables are clean and well connected at both ends.

???
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Sat Apr 27, 2013 1:43 pm

I removed the wiring harness. It had been repaired at some point, but did not appear to be damaged (measured around 0.3 ohms across each wire from one end to the other). The battery cable looks a bit frayed. Next step is to replace that and clean up all the other connections I can think of (trans ground strap, starter connections, etc...)

Off to India for work this week, so it will have to wait till next week. I would like to have this sorted out before Colin's visit, so we can work on other exciting stuff like the brake backing plates.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
dingo
IAC Addict!
Location: oregon - calif
Status: Offline

Re: Over Voltage

Post by dingo » Sun Apr 28, 2013 9:18 am

drober23 wrote:I did not get the alternator to a FLAPS yet.

I did swap in a spare alternator, and... overvoltage again. I swapped in a total of three voltage regulators (at least one known good last time it ran) with no change in the overvoltage.
this is sounding exactly like what i experienced....i guess i wasnt going crazy after all....(still never resolved mystery)
'71 Kombi, 1600 dp

';78 Tranzporter 2L

" Fill what's empty, empty what's full, and scratch where it itches."

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Mon Apr 29, 2013 8:44 am

Doesn't mean you're not going crazy :-0
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
Amskeptic
IAC "Help Desk"
IAC "Help Desk"
Status: Offline

Re: Over Voltage

Post by Amskeptic » Wed May 01, 2013 7:18 pm

drober23 wrote:Doesn't mean you're not going crazy :-0
I'm already here, water's great!
Colin :alien:

(really do those grounds nice, no funny stuff at battery cables like those stupid horrible clamp-the-strands type of el-junko terminal ends- also, be on the look-out for any evidence of grounding under the alternator cover, any whitish powder)
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Sat May 04, 2013 3:08 pm

Thanks for all the help in this thread folks. I think it is solved! But first a little back story... [edit - false alarm, over charge again]

I have been in India for work this week, training engineers from my company about one of our new products. Much of the time, I was preoccupied with the over-voltage problem. (Even folks from India love the bus photos :-), I end up talking a bit about the bus in many of my classes.) By the time the week was over, I had a plan.

Worked Friday, then got on the plane around midnight. Flew 9 hours to Paris, a few hours layover, then 9 hours to Detroit. Got in the car, and stopped to pick up a new negative battery cable, and some dielectric grease. Cleaned a bunch of grounds, and all the connectors on the starter post. Then I removedthe negative battery cable. I noticed it was pulling apart a bit. Aha! Here is what I saw:

Image

Put the new one in, tightened everything up, and put in the original distributor. This is the one that had been over charging, then stopped charging. It still didn't charge. Then I swapped in another spare, and it read 13.6 v at 3000 or so rpm!

Tomorrow I will tidy everything up and restore all the tin and the seal. For now, sleep! But a restful sleep.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

User avatar
drober23
Addicted!
Location: Metro Detroit
Status: Offline

Re: Over Voltage

Post by drober23 » Mon May 06, 2013 10:12 am

Well, I had one night of restful sleep.

Drove the bus to work today. After driving a bit, I checked the voltage. Over voltage again. Not sure what to do next.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

Post Reply