On 10/14/05, David Staten <Dastaten@earthlink.net> wrote:
If I remember my documentation, the injectors can power the Engine Controller. Specifically, the EC manual calls out for a switch to disconnect the injectors from the power supply, so that the EC doesn't remain powered and run the battery down.
Tracy does not recommend using the injectors to power the EC2 as the power from them is erratic at best. Also, whatever component is causing the bleed over was never intended to provide all the power to the EC2. That being said, it has functioned as an alternate power supply and will work in a pinch. My main power to my EC2 is from an automotive key switch that I do not have the utmost in confidence in. However, I fee reasonably comfortable knowing that the injector bleed through seems to work fine.
Also, if you have a standard aircraft master there should be no risk of them running down the battery. Except for an "always hot" line for clocks and stuff, the contactor should be the first thing that the battery power sees.
Having such a set-up does not mean that turning off you master will kill the engine. Once the engine is running the alternator will power everything even with the master switch off.
IMHO, the best way to turn off the engine is to turn of the fuel pump. This minimizes the fuel in the manifold and especially the engine itself - where it can cause the apex seal to stick if not used frequently. Same reason you turn off a lycoming by making the mixture full lean and opening up the throttle.
. If the Engine Controller is powered by this circuit, and the engine controller is connected to the monitor, its possible that there is some bleed current running to the EM as well. I am not sure specifically if there is supposed to be a path for current to bleed over or loop around like that, but it appears in your case that it does.
Sounds like we (chris and I) will need to come up with an "engine master switch" that will power the EC, EM, Injectors, Fuel Pump and Radiator Fan(s) on a common bus... in adition to a "master" and an "avionics master"