[Vwdiesel] Re: Starting a Rabbit D with no battery.

[LBaird119 at aol.com]

I don't remember a better thread for learning new things (for me). Wow. 
Especially about alternators needing external juice to induce the magnetic 
field. It's been an exceptionally good couple of days.

  That's what the "idiot light" is all about.  European Car had a really 
good article once on how useful an idiot light really is.  In many ways 
it's actually a better diagnostic tool than an ammeter!
  The alt. gets it's excitation power THROUGH the idiot light.  There's a 
diode in the circuit until 81 where the light IS a LED instead.  Turn on the 
key and power is now supplied, through the light, to the field.  Once it 
turns fast enough to make more power than it's using, it kind of hits 
critical mass, makes electricity and the light goes out.  A dim light 
usually means a poor connection or can mean a bad diode.  Coming 
on at higher rpm is usually brushes, etc.

> 
> So, I guess Loren's "pluck out the fuel shut-off and apply ether" gets the 
> prize for actually starting a Rabbit D in the winter that had no physical 
> battery at all. Gotta start carrying a can of ether.....
> 

  I had a GMC 6.2 lose the alt connection once and figured I'd just 
limp it on home the 15 miles.  Either didn't or just barely made it.  The 
glow plug contorller uses voltage to determine when to shut off the glow 
plugs.  The lower the voltage, the longer the "on" cycle.    Pretty soon 
they're on full time and the battery goes dead fast!  Until I got things 
fixed, 
I just unhooked the glow plugs.  A shot of ether and it fired up faster 
than ever and no heavy load of glow plugs that usually squeals the fan 
belt unless it's tight enough to ruin bearings.  If you've ever had a GM 
diesel, you know what I mean!
  Next time you curse the Bosch GP relay, just thing what it'd be like 
to have a GM GP controller instead!  :-P
     Loren