• From: Northern Illinois
  • Registered: 2004-03-27
  • Posts: 1,105

Topic: Odd Electrical Problem

I have a 73 convert here for a no crank after hour's drive & stop for gas issue. It was about an hour drive to me and when he dropped it off I noted the Alternator light did not come on when the key was on but engine not running. (It did however crank for me nice and strong). So the light is not functioning I thought but when I tapped the brakes, hit the power windows, wipers or anything with a good draw the Alt light would come on brightly for a millisecond & go back out.
I parked the car for the night to look at next morning & when I did the Alternator light is functioning normally. It also comes on if I unplug it and ground the wire. I'm going to go drive the car and get it hot but I'm guessing there is a short in the diode pack in the alternator and it acts up when hot.
Specs: Engine & trans rebuilt 3 years ago, new starter & bushing installed at that time along with a new internal regulator alternator.
I was wondering if this sounded familier to anyone.

-Darby
  • From: Cincinnati, Ohio
  • Registered: 2005-09-10
  • Posts: 2,336

Re: Odd Electrical Problem

Darby,

Here is a random thought.  Not sure if we are talking about a 73 Standard or Super Beetle Vert. 

But I think that 1973's still came with a generator (you mentioned an alternator quite a bit in your posting). 

So the alternator with internal regulator, is an aftermarket upgrade. 

Where I'm leading is...if the alternator is a replacement for the generator...and if the alternator has an integrated regulator (which usually requires the wires at the old regulator to be spliced together bypassing the old regulator)...then will the generator/alternator light on the speedo still work normally?

Just a thought...might help in eliminating the generator/alternator light as a source of info in troubleshooting the problem.



Otherwise...I was a little confused from your posting, on what exactly the problem is?

Is the problem that the car will not start after say an hour of driving...and if the car is stopped & the engine turned off for 5-10 minutes (say to get gas like you mentioned)...than when you try to restart it...it won't start??

And if it won't start...are you saying that the starter & engine will crank...but not actually start?

Just wanted to make sure I understood the question properly?

- Nick

p.s.  Does this Beetle really have electric windows!!!

1979 Super Beetle Convertible
  • From: Northern Illinois
  • Registered: 2004-03-27
  • Posts: 1,105

Re: Odd Electrical Problem

This is a 1973 Convertible, it came factory with an alternator with external regulator. When installing an internal regulated alternator into a generator or external regulator car you tie all B+ wires together under the back seat and run the new alternator's small spade terminal to the idiot light. This excites the alternator and causes it to charge. Thsi is all done correctly.
The car does not crank acts like the heat soak problem but will jump start immediately and without fail and yes this car has power windows.
Here is a picture before I installed the leather interior with Scat Procar seats and widened the rear wheels.
http://www.vwbug.com/cgi-bin/gi_v1.cgi?a=2&b=22

-Darby
  • From: Cincinnati, Ohio
  • Registered: 2005-09-10
  • Posts: 2,336

Re: Odd Electrical Problem

DrDarby wrote:

The car does not crank acts like the heat soak problem but will jump start immediately and without fail and yes this car has power windows.
Here is a picture before I installed the leather interior with Scat Procar seats and widened the rear wheels.
http://www.vwbug.com/cgi-bin/gi_v1.cgi?a=2&b=22

Yes...I've had this or similar starting problem previously when engine/starter is hot (after running for an hour or so in the Summer).  Was never really sure if it was the old starter or solenoid.  But when I replaced the starter & solenoid...everything was good.

Since you mentioned that the starter (and solenoid I am assuming) was installed new 3 years ago...I guess we could eliminate the starter/solenoid as the problem...unless the starter/solenoid is defective in some way.

Interesting that you said that the car will start no problem when jumped.


Here's maybe a crazy theory:

Assume that the starter/solenoid is bad or going bad on the Beetle, and that the "cranking amps" of the Beetle battery isn't enough to turn the "bad" starter on the Beetle because of the "heat soak" problem.

Then I am also assuming that the vehicle being used to jump the Beetle is a more modern vehicle (car/SUV/pick-up truck)...with a much stronger battery (cranking amps)...and with a much stronger alternator (total amps than the Beetle).

Maybe the stronger alternator and/or battery of the more modern vehicle is enough to turn-over the Beetle's "going bad" starter/solenoid when jumping the Beetle.

Of course this theory might be down the toilet if you are using another Beetle to jump the 73 Vert.

My humble suggestions:

1.  Make sure the 73 Vert's battery is 100% (not weak).
2.  Swap out the 73 Vert's starter & solenoid for a known good one.

That's my best "over the internet" guess.

Hope this helps, or sparks some ideas on your end.

- Nick

Last edited by Bug In My Nose (2007-07-16 13:10:26)

1979 Super Beetle Convertible
  • From: Northern Illinois
  • Registered: 2004-03-27
  • Posts: 1,105

Re: Odd Electrical Problem

The issue is... I know it isn't the starter. It is not a heat soak issue nor a bad starter, the amp draw on the starter is normal. I'm sure the problem is the car is not charging occasionally when it gets hot. The fact that the alternator light falls out of the circuit when hot has be bugged. An alternator will not charge with out a functional idiot light circuit but all of a sudden the idiot light works, when the car heats up id doesn't.  I've tested the bulb, the wire to the rear, respliced and tested it to the alternator. The battery was a year old, it does it too with my Miata's battery in it that is 6 weeks old. I've talked myself into a thermal short in the alternator or a shorted diode trio and am going to replace the alternator. I'm also going to install a starter relay just for sanity's sake.

-Darby