Isuzu G-series Twin Cam

just a question regarding the voltage regulator and where it supplies the ecu loom..

Basically my g200w came as a complete loom, but was missing the alternator/voltage regulator wiring - which I've now aquired a voltage regulator & for the most part alternator wiring..

I've worked out where to plug everything except the following:
from the ecu end its the same type of plug as the voltage regulators coloured black plug. Wires from that plug to ecu:
Blue, Green yellow, blue white, blue yellow, blue black, blue red.

My problem lies in the next part, the wiring from the alternator/regulator end. Im left with :
White , white blue, white red black, white black.

The white red has a fusable link on it, and continues white red.

The problem is all the whites dont go into any plug as the wrecker I sourced them from chopped it off! Also any genius will work out that I have 6 "blues" and 4 "whites". There is also another fusable link, but thats further down the alt/reg loom (this will be to the battery)

hope you can make some sense of that, Im also getting a Japanese girl on one of the nz forums to translate the wiring diagrams from the japanese workshop manual..

You'd be much better off with an alternator with inbuilt regulator.
I use Hitachi (aka Nissan, Mitsubishi) LR-170s (70A) as found on Pulsar N13 etc.
The N13s also use Bosch which is a bit simpler to wire - namely S to the battery +12V (no fuse needed, except top protect the wire), and the L to the normal White-Red charge-Lamp circuit.
(The Hitachi use an I = Ig = IgnPwr +12V instead of "S" which is ignition +12V, and cannot be too different from the battery's +12V voltage else overcharging will occur. An IGN controlled relay to connect battery +12V to the alternator/regulator's Ig terminal may be required.)


Anyhow, your White-Red from the alternator is the charge-Lamp circuit (aka "L" else D+ on alternators with inbuilt regulators) which goes to the charge lamp (obviously) and circuits like electric fuel pump (relay), carby or other fuel-cut solenoids, maybe electric chokes (but not the carby idle-air solenoid).

White is IgPwr (IGN +12V from IgKey)

White-Black is Field = F on alternator
White-bLue is probably White-Green - Neutral = N on alternator
Black is GND/Earth = E on alternator and to chassis/body (from regulator). This black blows if you have a bad engine to chassis ground strap etc.

Not that any of the above should relay go to the ECU - except perhaps the W-R charge-Lamp circuit. Power & ground should be from the battery rather than the alternator.


And make sure your ECU relay has polarity protection - ie, a series diode to the relay's solenoid so that the relay only energises with correct +12V & ground polarities.
(Do NOT confuse this with a parallel diode ACROSS the relay solenoid/coil which - if used - is for spike protection, but isn't required.)