The frequency valve is very similar to a Bosch fuel injector. If thats true then it should be designed with either a high or low impedance winding. Low impedance injectors should have a winding resistance of 1.7 to 3 ohms. They are opened with a current spike of 2.5 to 4 amps and help open with a current of .75 to 2 amps. High impedance injectors are usually 10 to 16 ohms. They are opened and held open with a about 1 amp. I believe both run at 12V. Putting 12V from a car battery across the injector will open it right up, at a very high amperage, and cause it to overheat quickly. You can actually feel it heat up in your hand. I wouldn't try this for more than 15 or 20 seconds at a time for crude testing purposes. A safer way to test is with a ballast resistor or 3 or more injectors in series. Jim