At 00:40 4/7/2000, Steve Delasalle wrote:

>Now, the bently book says that each plug pulls 12A, so am I right in
>thinking that
>each plug should have a resistance of 1ohm? (V=IR).

Right.  At working temperature.  At room temperature it is probably
considerably less.  Most ohmmeters won't measure this low a resistance
accurately, though, and in any case we don't know what it is without lots
more research or without heating the glow plug red hot.  That's why Bentley
tells you to measure the current draw instead.

>I've confirmed that I get 12V on the glow plug bus-bar.
>I've measure the resistance of each glow plug - to earth, and they are all
>open circuit.

So -- either you have a bad earth, or bad glow plugs (or a bad
meter).  Since the plugs appear to be earthed through the engine block, if
the block is properly earthed then the alternative is bad plugs.

I suspect that the controller failed in some way causing the plugs to run
continuously -- under diesel operating conditions I imagine this would
cause them to fail quickly.  That sort of puts you back to the beginning,
except with bad glow plugs... :-(  I hope I'm wrong, but I don't think so.

david

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"