Missing the Backup

The RWS EC3 engine controller has two sides to the computer, A&B. You normally run on A and this handles the ignition and the four fuel injectors. If there should be a plroblem with the A side, I flip a switch and go to B. I have set up the B side with a larger single mounted on the Jenvy throttle body. If you study the photo, you can see all five of the injectors.

When I do a run-up at 1,700 RPM and check the A/B performance it works just fine.  However, on my way back from AirVenture last year I got the bright idea to check the backup side while in flight. I flipped the switch to B and the engine basically crapped out. No chance of sustaining level flight.

So, for the last month I have been trying to resolve this problem. I have pretty much eliminated ignition, fuel pressure, mixture control, etc. Watching my EGT gauge, it's apparent that cylinder #3 is the one dropping out.

I watched some YouTube videos on fuel dispersion from injectors and see that many injectors shoot a strong stream of fuel. What I think is happening is when the mass airflow increases at higher RPMs, the fuel is probably concentrating towards the rear of the intake elbow, starving Cylinder #1.

This TB has a provision for two injectors, so I have ordered the parts to run with two.

Stay tuned for further developments.

The next three photos are a few years old, when I still was trying out the composite oil sump, but they help illustrate my setup.