Injector wiring

[Minirsp]

Hi all, very new to this, I'm currenrly building an A series engine with a BMW k1100lt motorbike head I have come to wiring the injectors and I have a yellow and a green/white coming from the injector how do I tell which is positive and which is negative

Thanks in advance Darren

[DaveEFI]

Injectors aren't polarity sensitive. But to keep things neat, I'd have yellow as the +12v, and yellow/stripe as the injector driver out. If using both MS injector drivers, the stripe should really be a different colour for each driver circuit.

[Minirsp]

Thanks for the quick reply Dave

One more question I have noticed on the wiring diagram me and from your comment you talk about using one or two banks my megasquirt wiring is lab led with four injector wires 1-4 does it matter which way I connect i.e. Should I connect cylinder 1 to injector one and so on or wire them in banks?

[DaveEFI]

There is an ideal grouping for injectors driven in two banks, according to the firing order. I'm sure someone will have it for the A series. Assuming this is a V3 beard, there are two injector drivers going to four terminals on the connector. So two of each are simply wired together internally. Which is why two are marked Inj1, two Inj2

For information, my RV8 came with factory injection grouped right bank and left bank. On going MS, I changed the grouping to that recommended for its firing order. In theory, it should give a slightly better idle, but isn't going to make a vast difference.