Bill,

I agree that once a logic level ground is applied to EC2 pin 30, it shouldn't matter where that connection comes from or how many there are.

It would be good to verify that I am understanding correctly the series of events described below:

"With the engine at idle, mixture at 14.7, disabling the secondary brings the mixture to about 13.0.  If I turn both disables on, and then turn cold start on, the mixture goes really rich around 10."

The first sentence seems straightforward but troubling as stated previously.

In the second sentence, are you saying that beginning with the engine running normally with the injector disable switches both off (normal operating position), you then turn both injector disable switches on?  At this point does the engine begin to die?  If it does, this is normal.  If you then turn on the cold start switch before the engine stops, does the engine recover and run very rich?  If it does, then this is not normal and the cold start switch is somehow supplying bus power to the injectors instead of supplying a logic ground to the EC2 pin 30.

This seems like quite a remote possibility, so I am probably not understanding your description correctly.

I now have 8 minutes of flight time on my P51 type cooling scoop and revised exhaust system.  Maybe a test flight to Texas is now in order?

Steve Boese