On Sun, 23 Jan 2005 06:48:44 GMT, (Dave Mundt)
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Yes, but only for starting. Once running the glow plugs are
switched off, right?

Actually...not really.

snip

A glow plug, by the by, is really
nothing more than a small heating element that sticks into the
cylinder and heats up to red-hot for a few moments when the engine
is first started. This extra heat is enough to ensure that combustion
will start, and, once the engine runs for a few minutes, it will have
warmed up enough that the ignition is self-sustaining.

snip

???