[Vwdiesel] Glow Plug testing ---- ( the FAST FAST way. ).

[Roger Brown]

Derek wrote:
> 
> I'll have to go try that.  As I understand it, if you have no voltage drop
> when probing from #1 to #2, that tells you that #2 is dead correct ?  How do
> you determine if #1 is dead ?  One more thing.  Which one is #1 ?  The one
> with the red wire /white stripe or the one near the timing belt ?

Makes little difference how you number the plugs.  The idea is if there is a voltage drop from one plug to the next, there must
be a current flowing between the plugs.  Since the current enters the bus bar at the flywheel end, start there.  If there is a
drop from the plug the wire and bus bar attach to to the next plug that only the bus bar attaches to, then there is current
flowing in the bus bar (V = I x R).  Assuming I and R are non-zero, V will also be non-zero.  Then go to the next pair of plugs,
should be less current in that leg, since there are now only 2 plugs left instead of 3.  Same with the last pair, only one plug,
so 1/3 the current and 1/3 the voltage drop more or less.  If the voltage drop is zero at any point, there is no current flowing
and all the plugs down stream are dead.  If the voltage drop stays the same as you go down the line, that means that the last
plug is good, but the middle ones are dead.  

Easy way to look at it is think of the bus bar as a plumbing manifold that has some valves attached to it.  You want to find out
if water is flowing out each valve (current), and all you can measure is the pressure (voltage) at each valve.  If the pressure
drops from valve to valve, then you have water flowing.  If the pressure is the same, then there is no water flowing.

--
   Roger

Note: The shop will be closed for the holidays.