[T2] Double relay half that is in bus; cross wires on injector plug (running engine externally).

[MUTS]

In setting up engine outside of bus, I have an injector plug (one on the 
harness) that cracked and 2 white wires fell off- am I right that the 
injector is an electromagnet that always gets a + input and the ECU 
provides the ground at the right time and duration for it to open? So 
does it matter which of 2 wires to an injector go where to the injector 
plug as I splice in a new plug??
    Also, one of the double relay mpc's is in the bus, going to front 
(ignition by key? and also I think to starter terminals- This obviously 
cannot reach the engine 6 ft away- Is it enough to run the fuel rail 
(pump energized) and have ignition (+ to coil) and then run starter- or 
is there a needed way for the (+) to reach the FI?

MUTS  = Michael's Ultimate Thumb Saver oboe, clarinet support
93 Chevy Roadtrek 210P
78 VW Westfalia Camper