LD20 Glow bus

[ANGRYLANCE]

Can some one explain the bus setup in the picture. I originally thought one wire was for + and the other - but then looking at it closer the "bus bar" for lack of a better discreption of one wire is only connected to the 2 back glow plugs. I assume the bus that connects to all the plugs is the one I should power and the ground is just through the body of the injector/block. So why is there separate power to the back 2 plugs in addition?
Thanks

[rlaggren]

Well, not my model and I don't stock FSM's like Al, but I'll take a WAG.

Assuming all the GP's are connected together (and I don't know why they'd not be) one wire may be the main glow and the 2nd may be the after glow from a different point in the GP circuit. My 2nd guess is that one wire is for the GP light.

The FSM is a big help and always a recommended purchase.


Cheers, Rufus

[ANGRYLANCE]

Thanks for the reply, like to have a FSM but cant find one.

[davehoos]

late model LD20 and RD28 use a series/paralell idea to split voltage for after glow.these are often not listed in parts or FSM.only in the model workshop updates.these use no dropping resister.
my 2 vehicles are slightly different with wiring.

front glow plugs are chasis earthed,rear are insulated these are different part numbers.
power is conected to white/blue wires--earth is conected to white/red. this is 12 volts across all plugs.
then 12 V is swaped onto the white/red.this splits voltage across the f/r pairs.

things to check.glow plugs when replaced are often swaped for front pairs.
and 12v are only used-no after glow,
or the insulators not fitted in the corect places.

[ANGRYLANCE]

Thanks Davehoos,
For the sake of simplicity and since I live in a very mild climate I am thinking about just running straight 12v on a momentary switch to power the GP's. Would there be a problem with this? I am thinking I can just hold power for 5 or 10 sec, if the thing runs then that is long enough. If it is smoking then maybe they need to be heated more. Dont really think I need the complexity of a glow plug controller. Only concern I have is burning up the plugs if I heat them too long.
Any comments?
Thanks

[davehoos]

for most of its life my LD20II had a wire from the startermotor solinoid terminal to reduce cost of extra relay and wiring..The glow plugs only got power when cranking and this is at a lower 8-11 volts.
just swaped the wire that was for the alternator to battery-it had the right eye terminals and fuse link.
when cold its possible to drain battery as there is no preglow-
this is a problem with other users of the car.

then with the sd23 auto timer i fitted--wired up the same as the early van,it rarley turned on unless it was near freezing.
then it would turn on directly from the key in the half start/crank possition..my problem was the engine often started when the glow plugs turned on or it drained the battery cranking..i had the bluebird run off in gear a few times with a few unsuspecting drivers just from turning on ignition for fuel level or milage.

i had an electric fuel pump that often needed to wait for it to prime up.

For the skyline i used the inhibit switch setup in the original auto trans conected to the neutral switch in the manual gearbox-pain when battery was low.i think it often switched on when changing gears.

the same problem occurs with most new diesels with glow plugs operation untill battery is drained--i get this at work doing auto elect work--i often need to turn off/on traicing wiring.pulling fuses for the plugs often not easy.

in the GM-commodore conversion it was switched using low power when the key was turned backwards into AUX.and using the brake fail test circuit.

the first bluebird conversion i did i had a wire with a pin conection that i held against the fuse box conections.when finger got hot i let go.other than rare cold starts it fired easy.

the old toyota landcruisers use an old design of an element in a metal cage indicator in the dash.these are used on very old english diesels.
turning on the key to glow you waited for the element winding to glow red hot in the fire proof cage.the hotter it gets the more it resists-this slops the glow plugs melting.