Right, Its all fitted and....... Its not working
After a lot of diagnosing, the circuits are both working as they should and are cutting off the field current to the alternator, however the alternator keeps producing voltage!
I finally worked out what's happening.
If the alternator is powered up then it stays powered up no matter what happens with the EXTERNAL field wire as it has an INTERNAL field feedback supply from a small 3 diode rectifier inside the alternator.
I'll have to pull the alternator apart and feed the internal field current to the pre-control relay side of the circuit to knock it out by the switching of the relays. It will then work.
I could just cut the link from the internal field supply, but this would then result in the battery (charge) light coming on whenever the alternator is working. I want to avoid this and have the system work as normally (transparent to the driver) as possible, and also have the warning light actually still work as a charge failure warning light!
Its good to hear the relays click in at 0% injector duty cycle and then back out again at >1%. I can actually hear the (potential) fuel savings LOL
One strange thing though, the duty cycle only reads up to 8% no matter what I do with the gas pedal. I think I may have peak hold injectors that need a small converter circuit to make the display work correctly. It'll have to wait though, as it works for switching the alternator so I'm not too bothered. Would be nice to see true duty cycle though.
Pictures to follow later
