[Vwdiesel] Monitoring GPs how it operates...
swright at zuiko.sls.bc.ca
Thu Dec 23 10:52:59 EST 2004
On 23 Dec 2004 at 10:23, Mark Shepherd <mark at shepher.fsnet.co.uk> wrote:
> As my descriptions are fairly 'piss poor' to say the least
> confusion is likely to reign which is why I'm going to
> explain operation (as I see it)...
> After car has started (or not) power to the glowplugs
> naturally turns off. These 4 circuits I'm introducing now
> use the glowplugs as a route to earth and the 4 LEDs will
> glow if their +ves are powered up.
> Once the plug dies and its driving supply switches off there
> is now no earth and the LED goes out as the 'power dode'
> stops the LED doing a 'terminator' and re-routing through
> the other good GPs }8OD)
> Your (my Patent) pretty display now shows only 3 out of 4
> LEDs glowing...Bingo :o) You can now say to your passenger
> service on no.2 cylinder required...
This sounds interesting, but I wonder how it will work if the GP does not fail "closed".
I have at least 6 dead GPs in the garage now, and I'm pretty sure some of them
failed with a high resistance in the 10k ohm range. This would equate to one mA of
current - is this enough to light an LED? I don't know...I suppose if it did, it would be
It might be helpful to have stats on the failure modes of GPs, percentages of failed
open vs failed high resistance.--
Shawnigan Lake School
More information about the Vwdiesel