Electrical Issues

[VDubber720]

Hey guys,
I have a 1974 VW Super Beetle that is giving me grief with the electrical (what's new, right?). About a year ago it developed the problem that when driving at night with the lights on the headlights and the gauge lights go dim sometimes and then will go back to bright. I can't figure out any rhyme or reason for what makes it go dim and then go back to being bright. Sometimes it'll go dim under acceleration other times not, sometimes it'll go dim a couple of seconds after the lights are on sometimes it'll be a couple of minutes. The problem came to a head when I started to have to get a jump from people to get my car rolling or bump start it (I got pretty creative on where I would park just in case a bump start was needed). I took it to an alternator shop a couple months back and had them test the alternator and regulator. The guy who did the test owns several VW so I trust his prognosis. He said that my battery was bad and that was what was causing the problem. It was an old batter that had sad unused for a couple of years so this was not to surprising to me. A new battery later the problem seemed to be resolved. Well the problem was resolved for about a month and now it's back. Any clues to what it is. I have an alternator and just went out and checked and I have an external voltage regulator.

[JerryMCarter1]

could be that your batery ground -- and tranny ground are bad
I would start with those.

I have also seen a bad red plus line -- covered in plastic and still be rotten inside

The wire from plus to the starter
Next time it will not start you might try to jump it like shown
carefull

Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[ashman40]

Could be battery/charging system. Measure voltage at battery terminals with everything OFF and while at fast idle (1500rpm).
12.6v is fully charged battery. 11.8v its fully discharged. Where is yours when everything is OFF?
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[VDubber720]

Thanks Jerry my ground strap is a little bit wonky so I'll try cleaning that up some and tidy up the wires that are grounded off the voltage regulator and see if that gives me success.

Ashman40 I have tried measuring those before and when off the reading is normal. I didn't get a chance to measure it at fast idle because I didn't have anybody to hold the pedal steady while I took readings. I'll try and rig up something with a broom stick and check that though. It does seem like somethings wrong with the charging system.

[JerryMCarter1]

You should have a fast idle cam on the carb linkage that you can either move the throttle up on one of the cams or just screw in the idle screw and get it to run to 1500 ( you could get by on the test with less than that.
You need 13.5 to 14.5 volts at the battery everything off -- when you do turn on the headlights you should get slightly the same -- which means the regulator is working properly

Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[VDubber720]

Thanks Jerry I had forgotten I could just use those notches on the throttle control on the carb. I'll give that a go and see what I get.

[ashman40]

[Cadaver]

why not photo of your engine and GEN/ALT
you do know, right that 1/2 are wrong. >? modified, or?
and the wiring under seat if this car had a voltage regulator there...
or that too is changed, now.
I think car came with AL82NC Alternator. stock. By Bosch of Germany.
74 is a transitional year, so photos are required.
and is internally regulated.
it can be removed. that reg.
to do so see this.
see link 2 and 3 here
got this?
http://ac-vw-remove.com/How_to_fix_it/electrics/generator/gen.html#AL82N



get a dash volt meter
then when the regulator goes nuts, it's in your face that fact.
if not up to that , then connect a cheap volt meter to the battery
lay it on the rear seat or passenger, so you can glance at it. $10 meter.

the correct ranges is 12.8v stalled engine. (summer 100% charged)
13.3 to 15v running
the voltage depends on the battery state of charge . ( and gen case temperatures)
the higher volts is , i'm charging heavy NOW.

if you took a battery to a store and it was discharged they will tell you its bad.
(its you job to charge it first, then take it in, or your out $100 bucks)
a charger is cheap. cheaper than lead. for sure.

the reg in these cars can go nuts and blow up every lamp in the car
and the radio, it can go to 20vdc. way bad that. a hard fail !
and roast a new battery. , even splits a case. acid all over....

so running VM free, is not all that good an idea.
it's old school. drive and pray tech.

The SOC charts can very by makers. there are 3 types@!
my battery runs 12.8. (12.66 is more likely for yours) 100% charged.
but most work like this .
http://ac-vw-remove.com/How_to_fix_it/electrics/nocrank/soc2a.jpg

only fully charged and rested 4 hours, does the voltage make sense.
(this bleeds off surface charge , acid gradients
_________________
for sale now.
in Samba classifieds....1968 T1.

[Cadaver]

broom

no GF , wife, or kid about. so wood rod time.
no neighbors either?
_________________
for sale now.
in Samba classifieds....1968 T1.

[VDubber720]

Thanks for all the replies. I measured the battery with everything off and got 12.8ish (on the higher side). I measured with the engine at idle and got the same thing. I'm new to all this but that seems bad. I took some pics of the alternator and regulator. It might be hard to see but the alternator is a Motorola (which means a replacement from the original).
http://m.flickr.com/#/photos/68835702@N04/7558813070/
http://m.flickr.com/#/photos/68835702@N04/7558811382/

Well the bad news train continues to chug on. Starting yesterday the alternator dummy light no longer goes out all the time (a bad omen I know). I have to be up on the throttle to get it to turn off and if I'm stopped at a stop light it'll come back on. It's also now making a whining/whirring noise.

To me this means it's definitely time for an alternator rebuild or a new alternator. Does that sound right to ye VW gods?
[/img]

[cletus_zuber]

That 74 alt is 38 years old, its wore out. get a new 2 wire alt as pictured here:

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC-043-903-023-A

or try a new voltage regulator:

http://www2.cip1.com/ProductDetails.asp?ProductCode=BOS-0-190-600-017


better get a new pulley while you're there, your old one ain't gonna come off.

I found it cheaper a few years ago to buy the gen-to-alt conversion kit, and just toss the cheap tin and alt stand that comes with it.

http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC-C10-5750-KT

you can do this "engine in car", it ain't easy but can be done, do a search to find the how-to's
_________________
1972 1302
HPMX 40's & 019

[bugnrob]

I have one of those regulators (I also have a 74) but have switched to the internally regulated alternator. You can have it for a low price if you want to try that first. Send me a PM if interested.
_________________
-----------------------------
74 Super Beetle - Sunroof, Western Wheels

[VDubber720]

I'm going to be out of town this weekend but Monday I'm taking it by the alternator shop and see what the fellas can tell me. It seems like the issue at this point has got to be the alternator. If it turns out to be the regulator I'll give you a shout.

[Cadaver]

if it was charging ok before, may it will still with new bearings.
seems it was, as you drove it and the battery didnt flat line........

$10 to find out.

but the best fix for sure the new Bosch, no denial there.
_________________
for sale now.
in Samba classifieds....1968 T1.

[VDubber720]

Yeah I'm hoping they say something like it just needs new bearings.

[JerryMCarter1]

You need 13.5 to 14.5 - volts at the battery when it is above idle
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[VDubber720]

Well I took the car to the alternator shop and it turns out the stator was bad. So they replaced that and I thought we were good to go. The car does seem to be cured of the alternator dummy light coming on so that's a good sign. I drove it home from work tonight with the lights on and they were bright which I figured was a good sign. After about 5 minutes of driving though the headlights went dim as well as the speedo lights. AAAARRRGGG! I haven't had the chance to get my voltmeter out and test things but I was really thinking that the alternator working right would fix the headlights issue. What do y'all think?

[JerryMCarter1]

my 73 vert does the same thing -- I think there was a big discussion about it a few months ago -- It was around the idea of bad grounds and the regulator kicking in -- they also solved a lot of it with a relay to take the load off of the headlight switch -- I have not done it yet
I would private message Ashman and get with him on a one to one basis.
I am too busy right now

Jerry
_________________
Experience always triumphs over hearsay and You get to select which theory to believe

[ashman40]

[Cadaver]

what ALT, BOSCH or MOT? ,its external my guess is the BOSCH.

use a voltmeter
(not HL dimming as that can be normal under certain battery states)
monitor the alternator actions (across battery terms) use a DMM.
record them
at cold idle
hot idle (900)
and driving
and stopped.
key off, what is the battery voltage , in morning (rested_ and after a drive.)

measure across the battery
then measure at the fuse box 74sb is
at fuse. #S8
what is the voltage doing there. that is the main power feed point.
doing key off?
key on?
idling?
the turn on head lights ,what is the voltage now.?

this data shows me what is going on and where there are voltage drops.
_________________
for sale now.
in Samba classifieds....1968 T1.