Jesse
Well Known Member
I am trying to work through a problem we are having with an RV-10 with an IO-540 and EFII. We have gotten to the point where we can get Cylinder 1 to drop (complete EGT drop and engine runs rough) by running the engine at 2500 rpm. The manifold pressure doesn't matter. We have replaced the injector. We have swapped the injector power wire with cylinder 3 (to verify it isn't a bad crimp). We have changed ECU's vie the ECU 1/2 switch. We have run on both and either mag individually. Nothing gets rid of this problem. At 2530 rpm there is no problem. At 2450 rpm there is no problem. At 2500 on the money, it drops cylinder 1. No other cylinder, and no exception. Every time, cold engine or hot engine, lean or rich, in flight or on the ground.
My main questions is, what could possibly be magic about 2500 rpm that could make this happen.
We though about a stuck valve at some point, but that would not just be at one specific rpm, at least not that I could imagine.
Thoughts?
My main questions is, what could possibly be magic about 2500 rpm that could make this happen.
We though about a stuck valve at some point, but that would not just be at one specific rpm, at least not that I could imagine.
Thoughts?