EFI engine shutdown
 

Is there a preferred method for shutting down an EFI Lycoming? Just turn off the master like on a car, or shut the fuel pump off?

Obviously both will shut the engine down. I was interested because of a wiring logic I would like to use.

I have been using EFII for 4 years and 800 hours now in my RV10. Shutting down starts with shutting both ECU units, then master.

engine should run with master contactor open
 

IMO opening the master contactor should not kill the engine. In case of fire in the cockpit you should be able to open the master contactor and still have engine power and if the master contactor fails you should still have engine power. Stop the engine with coil, injector, or pump power your choice but kill them and the ECU within a few seconds of one another. SDS in their 6 cylinder dual ECU installation instruction says to "NEVER switch off ECU power to verify coil pack operation" so I take it as good advice to shut down the coilpacks before the ECU for EFI systems in general.

Having the engine continue to run with the battery disconnected or master off was my intention and the reason for the question.

Thanks for the responses.

I have mine set up so that I can toggle an emergency bus switch which will give power to the essential buss that the engine runs on. So on a normal shutdown I just turn the master off and the engine dies. If I engage the emergency bus switch first, the engine will keep running with the master off.

You can kill coil or injector power or shut off the pumps.

Is there a reason you can't just pull the mixture to cutoff first?

The mixture knob will reduce the AFR by 50% so if idle is set up for about 13 to 1 at the normal 12 O'clock position, this should kill the engine too. Just don't forget the position when you try to restart again.

Any downside to just killing the fuel pump first?

I'd think this is identical to mixture cutoff for shutting down a carb engine.