We do not have one of these in our shop right now. The way it functions is. When starting cold, The ECU pulses the injector at a fixed rate. Once the temp sensor reaches a given temp reading the ECU switches to closed loop mode. The pulsing is regulated buy the ECU based in inputs from the cam sensor, the throttle position sensor and the O2 sensor. At idle, the only fuel supplied to the engine is through the trim injector. Once throttled above idle the regulator starts supplying fuel directly to the carb. If you have a fixed voltage to the trim injector all the time the fuel will be delivered in a constant stream and the mixture will be too rich to fire. With the voltage you are seeing at the injector feed wires, I would guess there is a ECU problem or you have a short from a battery wire to the injector supply wire.