Quote:

---

Does anyone who has put comments on this post understand current flow in D.C.(Direct Current) circuits? If I understand(edited) the operation of the electrcial operated injectors on EFI systems they pulse the negative(battery) side of the injector with -5.5 volts, correct , ? If so then doesn't all the elecrtons need to return to thier source to complete the circuit?(make the injectors pulse) That being said you might want to follow the instructions from the manufacture to the T

---

Probably not correct . Factory EFI systems usually feed 12V+, NOT 5.5 VOLTS to the injectors, along with 12V+ to the coil from the same circuit. Then, yes, they do pulse the ground circuits to cycle the injectors and coil. The 5.5 volt circuit is usually the sensor voltage circuit - MAP sensor, CPS, TPS, O2's, etc. Since most of the factory EFI's can use the same injectors as the aftermarket MPFI's do, safe bet the aftermarket uses 12V for their systems, too.

As to the alternator/noise issue - I can tell you that the "purity" of the DC current can vary greatly from alt to alt. Installing high dollar stereo systems years ago taught me a simple test - when you can unplug the alt field wires from the alt when the engine was running and the whine in the speakers would usually go away - well, common sense tells you it isn't the ignition making the noise.

Oops, almost forgot